AIM: To examine the expression of high mobility group box-1(HMGB-1) and intercellular adhesion molecule-1(ICAM-1) in the retina and the hippocampal tissues; and further to evaluate the association of these two mo...AIM: To examine the expression of high mobility group box-1(HMGB-1) and intercellular adhesion molecule-1(ICAM-1) in the retina and the hippocampal tissues; and further to evaluate the association of these two molecules with the alterations of blood-retinal barrier(BRB) and blood-brain barrier(BBB) in a rat model of type 2 diabetes.METHODS: The type-2 diabetes mellitus(DM) model was established with a high-fat and high-glucose diet combined with streptozotocin(STZ). Sixteen weeks after DM induction, morphological changes of retina and hippocampus were observed with hematoxylin-eosin staining, and alternations of BRB and BBB permeability were measured using Evans blue method. Levels of HMGB-1 and ICAM-1 in retina and hippocampus were detected by Western blot. Serum HMGB-1 levels were determined by enzyme-linked immunosorbent assay(ELISA).RESULTS: A significantly higher serum fasting blood glucose level in DM rats was observed 2wk after STZ injection(P 〈0.01). The serum levels of fasting insulin,Insulin resistance homeostatic model assessment(IRHOMA),total cholesterol(TC), total triglycerides(TG) and low density lipoprotein cholesterol(LDL-C) in the DM rats significantly higher than those in the controls(all P 〈0.01).HMGB-1(0.96±0.03, P 〈0.01) and ICAM-1(0.76±0.12, P 〈0.05) levels in the retina in the DM rats were significantly higher than those in the controls. HMGB-1(0.83±0.13, P 〈0.01) and ICAM-1(1.15 ±0.08, P 〈0.01) levels in the hippocampal tissues in the DM rats were alsosignificantly higher than those in the controls. Sixteen weeks after induction of DM, the BRB permeability to albumin-bound Evans blue dye in the DM rats was significantly higher than that in the controls(P 〈0.01).However, there was no difference of BBB permeability between the DM rats and controls. When compared to the controls, hematoxylin and eosin staining showed obvious irregularities in the DM rats.CONCLUSION: BRB permeability increases significantly in rats with type-2 DM, which may be associated with the up-regulated retinal expression of HMGB-1 and ICAM-1.展开更多
Astrocytes are intimately involved in the formation and development of retinal vessels. Astrocyte dysfunction is a major cause of blood-retinal barrier injury and other retinal vascular diseases. In this study, the de...Astrocytes are intimately involved in the formation and development of retinal vessels. Astrocyte dysfunction is a major cause of blood-retinal barrier injury and other retinal vascular diseases. In this study, the development of the retinal vascular system and the formation of the blood-ret-inal barrier in mice were investigated using immunolfuorescence staining, gelatin-ink perfusion, and transmission electron microscopy. The results showed that the retinal vascular system of mice develops from the optic disc after birth, and radiates out gradually to cover the entire retina, taking the papilla optica as the center. First, the superifcial vasculature is formed on the inner retinal layer;then, the vasculature extends into the inner and outer edges of the retinal inner nuclear layer, forming the deep vasculature that is parallel to the superifcial vasculature. The blood-retinal barrier is mainly composed of endothelium, basal lamina and the end-feet of astrocytes, which become mature during mouse development. Initially, the naive endothelial cells were immature with few organelles and many microvilli. The basal lamina was uniform in thickness, and the glial end-feet surrounded the outer basal lamina incompletely. In the end, the blood-retinal barrier matures with smooth endothelia connected through tight junctions, rela-tively thin and even basal lamina, and relatively thin glial cell end-feet. These ifndings indicate that the development of the vasculature in the retina follows the rules of“center to periphery”and“superifcial layer to deep layers”. Its development and maturation are spatially and tempo-rally consistent with the functional performance of retinal neurons and photosensitivity. The blood-retinal barrier gradually becomes mature via the process of interactions between astro-cytes and blood vessel cells.展开更多
AIM: To investigate the role of moesin and its underlying signal transduction in retinal vascular damage induced by retinal ischemia-reperfusion(RIR) insult.METHODS: C57 BL/6 mice were subjected to continued ischemia ...AIM: To investigate the role of moesin and its underlying signal transduction in retinal vascular damage induced by retinal ischemia-reperfusion(RIR) insult.METHODS: C57 BL/6 mice were subjected to continued ischemia for 45 min, followed by blood reperfusion. The expression and phosphorylation of moesin in retinal vessels were detected by immunohistochemistry and Western blotting. The inner blood-retinal barrier was evaluated using FITCdextran leakage assay on whole-mount retina. Further studies were conducted to explore the effects of p38 mitogen-activated protein kinase(MAPK) pathway on the involvement of moesin in RIR-evoked retinal vascular hyperpermeability response. RESULTS: It revealed that RIR induced moesin phosphorylation in a time-dependent manner after reperfusion. The phosphorylation of moesin was alleviated by inhibitions of p38 MAPK, while this treatment also ameliorated the dysfunction of inner blood-retinal barrier. CONCLUSION: The results suggest that moesin is involved in RIR-evoked retinal vascular endothelial dysfunction and the phosphorylation of moesin is triggered via p38 MAPK activation.展开更多
AIM: To evaluate the therapeutic effect of fluorofenidone on disrupted blood-retinal barrier in the diabetic mice and uncover its underlying mechanism. METHODS: db/db mice were randomly chosen for treatment with da...AIM: To evaluate the therapeutic effect of fluorofenidone on disrupted blood-retinal barrier in the diabetic mice and uncover its underlying mechanism. METHODS: db/db mice were randomly chosen for treatment with daily doses of fluorofenidone or placebo at 5-week-old, treatment continued until mice reach 24-week- old. Then, expression of transcriptiona factor insulin gene enhancer binding protein-1 (Islet-I) and vascular endothelial growth factor (VEGF) in murine retinas were evaluated. Retinal vascular permeability was assessed by examining the level of albumin in db/db murine retinas. Furthermore, the retinal vessel tight junction was estimated by checking the level of occludin in the murine retinal tissues. RESULTS: After occurrence of diabetic retinopthy in db/ db mice, expressions of transcritpional factor Islet-1 was found to be upregulated in db/db murine retinas compared with non-diabetic controls. Similar to expression pattern of Islet-l, VEGF were also demonstrated to be increased in retinas of db/db mice, which was accompanied by increased retinal vascular leakage and decreased tight junction protein level. Systemetic administration of fluorofenidone repaired broken retinal vascular tight junction by restoring occludin expression in db/db retinal tissue. Consequently, retinal vascular premeability were indicated to be reduced by examining the transudative albumin level in diabetic retinal tissues. Both Islet-1 and VEGF expression were inhibited in the retinas of db/db mice after treatment with fluorofenidone. CONCLUSION: Fluorofenidone significantly protectes retinal tight junction and reduces retinal vascular leakage. The phenomenon can be partially attributed to reducing overexpression of Islet-1 and VEGF in diabetic retinal tissues.展开更多
AIM: To clarify the role of inducible nitric oxide synthase(i NOS) in blood-retinal barrier(BRB) injury after acute high intraocular pressure(IOP) in rats.METHODS: Forty-two Sprague-Dawley(SD) rats were randomized int...AIM: To clarify the role of inducible nitric oxide synthase(i NOS) in blood-retinal barrier(BRB) injury after acute high intraocular pressure(IOP) in rats.METHODS: Forty-two Sprague-Dawley(SD) rats were randomized into 7 groups [control(Cont), 3, 6, 12, 24, 48, and 72 h, n=6]. Except Cont group, other groups’ retina tissue was obtained at corresponding time points after a model of acute high IOP have been established in rats. The expression of i NOS and tight junction protein zonula occludens(ZO)-1 was detected by Western blotting. Evans blue(EB;3%) was injected into the great saphenous vein to detect the leakage of EB by spectrophotometer. Nine rats were divided into Cont, 6 h, 12 h groups, the expression of i NOS was localized by immunofluorescence. In order to verify the role of i NOS in the damage to BRB, thirty-six rats were randomly divided into 4 groups [Cont, Cont+inhibitor(Inh), 6 h and 6 h+Inh, n=9]. After treatment with the i NOSspecific inhibitor 1400 W, the expression of i NOS and ZO-1 and the leakage of BRB were detected again.RESULTS: The immunofluorescence results showed that the expression of i NOS was observed in the Cont group and 6 h group, but not in the 12 h group. i NOS was mainly expressed in the retinal nerve fiber layer, ganglion cell layer and inner nuclear layer and that it did not colocalize with the retinal ganglion cell marker Neu N but was co-expressed with the vascular endothelial cell marker CD31. Western blotting showed that in the early period(3 h, 6 h) after acute high IOP, the expression of i NOS was upregulated, then the down-regulation of i NOS were tested in the follow-up timing spots. ZO-1 expression showed a continuous downregulation after 6 h. The quantitative results for EB showed that the amount of EB leakage began to increase at 3 h after acute high IOP. At 6 h, the leakage of EB was lower, but at 12 h, the leakage of EB was highest, after which it gradually recovered but remained higher than that in the Cont group. The expression of i NOS was down-regulated after 1400 W treatment. ZO-1 expression was not significantly changed in the Cont+Inh group and the 6 h group, and significantly down-regulated in the 6 h+Inh group, and the leakage of EB was significantly increased after 1400 W treatment.CONCLUSION: These results suggest that the upregulation of i NOS expression in the early stage after acute high IOP may have a protective effect on BRB injury.展开更多
AIM:To observe the effects of the inhibition of NADPH oxidase 4(NOX4)expression on the retinal vascular barriers and visual function after retinal detachment(RD).METHODS:RD model was established 3 wk after adenoassoci...AIM:To observe the effects of the inhibition of NADPH oxidase 4(NOX4)expression on the retinal vascular barriers and visual function after retinal detachment(RD).METHODS:RD model was established 3 wk after adenoassocianed virus vector injection.The retinal tissue was harvested 3 d after RD,and the death of retinal vascular endothelial cells and photoreceptors was observed using electron microscopy.The NOX4 expression was detected by Western blot.Confocal microscopy was used to observe a retinal patch that had been perfused with Evans blue.A modified water maze test was used to detect the time required to find the platform on the water surface.The visual function of the rats was evaluated and reactive oxygen species(ROS)expression was detected by a fluorescence microplate reader.RESULTS:The retinal patch showed that NOX4 interference significantly reduced the destruction of the tight junctions between the retinal endothelium of RD rats and reduced leakage.Western blotting showed decreased expression of the NOX4 protein and decreased expression of ROS in retinal tissue;the Morris water maze test results showed that NOX4 interference significantly decreased the escape latency of the rats.CONCLUSION:NOX4 interference reduces the production of ROS in retinal vascular endothelial cells after experimental RD,thereby protecting the blood-retinal barrier and protecting visual function.展开更多
AIM:To elucidate the role of vascular endothelial growth factor-165b(VEGF-165b)in blood-retinal barrier(BRB)injury in the rat acute glaucoma model.METHODS:In this study,the rat acute high intraocular pressure(HIOP)mod...AIM:To elucidate the role of vascular endothelial growth factor-165b(VEGF-165b)in blood-retinal barrier(BRB)injury in the rat acute glaucoma model.METHODS:In this study,the rat acute high intraocular pressure(HIOP)model was established before and after intravitreous injection of anti-VEGF-165b antibody.The expression of VEGF-165b and zonula occludens-1(ZO-1)in rat retina was detected by double immunofluorescence staining and Western blotting,and the breakdown of BRB was detected by Evans blue(EB)dye.RESULTS:The intact retina of rats expressed VEGF-165b and ZO-1 protein,which were mainly located in the retinal ganglion cell layer and the inner nuclear layer and were both co-expressed with vascular endothelial cell markers CD31.After acute HIOP,the expression of VEGF-165b was up-regulated;the expression of ZO-1 was down-regulated at 12h and then recovered at 3d;EB leakage increased,peaking at 12h.After intravitreous injection of anti-VEGF-165b antibody,the expression of VEGF-165b protein was no significantly changed;and the down-regulation of the expression of ZO-1 was more obvious;EB leakage became more serious,peaking at 3d.EB analysis also showed that EB leakage in the peripheral retina was greater than that in the central retina.CONCLUSION:The endogenous VEGF-165b protein may protect the BRB from acute HIOP by regulating the expression of ZO-1.The differential destruction of BRB after acute HIOP may be related to the selective loss of retinal ganglion cells.展开更多
The blood-brain barrier(BBB)is an essential component in regulating and maintaining the homeostatic microenvironment of the central nervous system(CNS).During the occurrence and development of glioblastoma(GBM),BBB is...The blood-brain barrier(BBB)is an essential component in regulating and maintaining the homeostatic microenvironment of the central nervous system(CNS).During the occurrence and development of glioblastoma(GBM),BBB is pathologically destroyed with a marked increase in permeability.Due to the obstruction of the BBB,current strategies for GBM therapeutics still obtain a meager success rate and may lead to systemic toxicity.Moreover,chemotherapy could promote pathological BBB functional restoration,which results in significantly reduced intracerebral transport of therapeutic agents during multiple administrations of GBM and the eventual failure of GBM chemotherapy.The effective delivery of intracerebral drugs still faces severe challenges.However,strategies that regulate the pathological BBB to enhance the transport of therapeutic agents across the barrier may provide new opportunities for the effective and safe treatment of GBM.This article reviews the structure and function of BBB in physiological states,the mechanisms underlying BBB pathological fenestration during the development of GBM,and the therapeutic strategies of GBM based on BBB intervention and medicinal drugs transporting across the BBB.展开更多
Our previous study verified the protective effects of Lycium barbarum polysaccharides(LBP)on retinal neurons and blood vessels in acute ocular hypertension(AOH)mice.To investigate the effect of LBP on the reactivity o...Our previous study verified the protective effects of Lycium barbarum polysaccharides(LBP)on retinal neurons and blood vessels in acute ocular hypertension(AOH)mice.To investigate the effect of LBP on the reactivity of retinal glial cells,an AOH mouse model was established in one eye by maintaining ocular hypertension of 90 mm Hg for 60 minutes.Either LBP solution(1 mg/kg)or phosphate-buffered saline was administrated to the mice by gavage daily,starting 7 days before the AOH insult and continuing until the mice were sacrificed for specimen collection on day 4 post-insult.After AOH insult,increased numbers of astrocytes and microglia were observed,together with decreased expression of the following glial cell biomarkers in the retinal ganglion cells of AOH mice:glial fibrillary acidic protein,glutamine synthetase,aquaporin-4,S-100 proteins,ionized calcium-binding adaptor molecule 1,amyloid precursor protein and receptor of advanced glycosylation end-products.After intervention with LBP,the above changes were significantly reduced.Remarkably,morphological remodeling of blood vessel-associated retinal astrocytes,marked by glial fibrillary acidic protein,was also observed.These results,taken together,suggest that LBP regulated the production of amyloid-βand expression of receptor of advanced glycosylation end-products,as well as mediating the activity of retinal glial cells,which may lead to the promotion of better maintenance of the blood-retinal barrier and improved neuronal survival in AOH insult.This study was approved by the Committee for the Use of Live Animals in Teaching and Research(approval No.CULTRA-#1664-08).展开更多
Blood-brain barrier disruption occurs in the early stages of Alzheimer’s disease.Recent studies indicate a link between blood-brain barrier dysfunction and cognitive decline and might accelerate Alzheimer’s disease ...Blood-brain barrier disruption occurs in the early stages of Alzheimer’s disease.Recent studies indicate a link between blood-brain barrier dysfunction and cognitive decline and might accelerate Alzheimer’s disease progression.Astrocytes are the most abundant glial cells in the central nervous system with important roles in the structural and functional maintenance of the blood-brain barrier.For example,astrocytic cove rage around endothelial cells with perivascular endfeet and secretion of homeostatic soluble factors are two major underlying mechanisms of astrocytic physiological functions.Astrocyte activation is often observed in Alzheimer’s disease patients,with astrocytes expressing a high level of glial fibrillary acid protein detected around amyloid-beta plaque with the elevated phagocytic ability for amyloid-beta.Structural alte rations in Alzheimer’s disease astrocytes including swollen endfeet,somata shrinkage and possess loss contribute to disruption in vascular integrity at capillary and arte rioles levels.In addition,Alzheimer’s disease astrocytes are skewed into proinflammatory and oxidative profiles with increased secretions of vasoactive mediators inducing endothelial junction disruption and immune cell infiltration.In this review,we summarize the findings of existing literature on the relevance of astrocyte alte ration in response to amyloid pathology in the context of blood-brain barrier dysfunction.First,we briefly describe the physiological roles of astrocytes in blood-brain barrier maintenance.Then,we review the clinical evidence of astrocyte pathology in Alzheimer’s disease patients and the preclinical evidence in animal and cellular models.We further discuss the structural changes of blood-brain barrier that correlates with Alzheimer’s disease astrocyte.Finally,we evaluate the roles of soluble factors secreted by Alzheimer’s disease astrocytes,providing potential molecular mechanisms underlying blood-brain barrier modulation.We conclude with a perspective on investigating the therapeutic potential of targeting astrocytes for blood-brain barrier protection in Alzheimer’s disease.展开更多
AIM: To clarify the mechanism of infliximab treatment in diabetic macular edema (DME) and to provide a new alternative therapy for DME. METHODS: Rats were randomly divided into the control group, the model group ...AIM: To clarify the mechanism of infliximab treatment in diabetic macular edema (DME) and to provide a new alternative therapy for DME. METHODS: Rats were randomly divided into the control group, the model group and the infliximab treatment group. A diabetic rat model was created. The concentration of TNF-α in the vitreous body was detected by ELISA. The expressions of B-Raf, p38, claudin-1 and occludin in the retina were detected by Western blot. The integrity of the blood retinal barrier (BRB) was measured using Evan's blue as a tracer. RESULTS: After three months and six months of the diabetes model, the vitreous TNF-α level in the model group was higher than that of the control group. It was also higher in treated group than that of the control group but was lower than that of the model group. The differences among the three groups were statistically significant (at 3mo, F=857.098, P〈0.001; 6mo, F=1261.897, P〈0.001). The retina B-Raf and p38 levels in the model group were higher than that of the control group. They were also higher in treated group than that of the control group but were lower than that of the model group. The differences among the three groups were statistically significant (B-Raf at 3mo, F=106.596, P〈0.001 and at 6mo, F=200.681, P〈0.001; p38 at 3mo, F=41.662, P〈0.001 and at 6mo, F=67.979, P〈0.001). The retina claudin-1 and occludin levels in the model group were lower than that of the control group. They were also lower in treated group than that of the control group but were higher than that of the model group. The differences among three groups were statistically significant (claudin-1 at3mo, F=-139.088, P〈0.001 and at 6mo, F=128.415, P〈0.001; occludin at 3mo, F=-92.733, P〈0.001 and at 6mo, F--104.478, P〈0.001). The retinal Evans blue leakage in the model group was higher than that of the control group. It was also higher in treated group than that of the control group but was lower than that of the model group. The differences among the three groups were statistically significant (at 3mo, F=-447.946, P〈0.001; at 6mo, F'=-1610.732, P〈0.001). CONCLUSION: In-α diabetic rat model, infliximab may relieve TNF-α induced BRB breakdown via the B-Raf and p38 signaling pathway.展开更多
Clinical ophthalmologists consider each retinal disease as a completely unique entity.However,various retinal diseases,such as uveitis,age-related macular degeneration,diabetic retinopathy,and primary open-angle glauc...Clinical ophthalmologists consider each retinal disease as a completely unique entity.However,various retinal diseases,such as uveitis,age-related macular degeneration,diabetic retinopathy,and primary open-angle glaucoma,share a number of common pathogenetic pathways.Whether a retinal disease initiates from direct injury to the blood-retinal barrier(BRB)or a defect/injury to retinal neurons or glia that impairs the BRB secondarily,the BRB is a pivotal point in determining the prognosis as self-limiting and recovering,or developing and progressing to a clinical phenotype.The present review summarizes our current knowledge on the physiology and cellular and molecular pathology of the BRB,which underlies its pivotal role in the initiation and development of common retinal diseases.展开更多
基金Supported by the Project of Education Bureau Foundation of Hubei Province(No.Q20151901)
文摘AIM: To examine the expression of high mobility group box-1(HMGB-1) and intercellular adhesion molecule-1(ICAM-1) in the retina and the hippocampal tissues; and further to evaluate the association of these two molecules with the alterations of blood-retinal barrier(BRB) and blood-brain barrier(BBB) in a rat model of type 2 diabetes.METHODS: The type-2 diabetes mellitus(DM) model was established with a high-fat and high-glucose diet combined with streptozotocin(STZ). Sixteen weeks after DM induction, morphological changes of retina and hippocampus were observed with hematoxylin-eosin staining, and alternations of BRB and BBB permeability were measured using Evans blue method. Levels of HMGB-1 and ICAM-1 in retina and hippocampus were detected by Western blot. Serum HMGB-1 levels were determined by enzyme-linked immunosorbent assay(ELISA).RESULTS: A significantly higher serum fasting blood glucose level in DM rats was observed 2wk after STZ injection(P 〈0.01). The serum levels of fasting insulin,Insulin resistance homeostatic model assessment(IRHOMA),total cholesterol(TC), total triglycerides(TG) and low density lipoprotein cholesterol(LDL-C) in the DM rats significantly higher than those in the controls(all P 〈0.01).HMGB-1(0.96±0.03, P 〈0.01) and ICAM-1(0.76±0.12, P 〈0.05) levels in the retina in the DM rats were significantly higher than those in the controls. HMGB-1(0.83±0.13, P 〈0.01) and ICAM-1(1.15 ±0.08, P 〈0.01) levels in the hippocampal tissues in the DM rats were alsosignificantly higher than those in the controls. Sixteen weeks after induction of DM, the BRB permeability to albumin-bound Evans blue dye in the DM rats was significantly higher than that in the controls(P 〈0.01).However, there was no difference of BBB permeability between the DM rats and controls. When compared to the controls, hematoxylin and eosin staining showed obvious irregularities in the DM rats.CONCLUSION: BRB permeability increases significantly in rats with type-2 DM, which may be associated with the up-regulated retinal expression of HMGB-1 and ICAM-1.
基金supported by the National Natural Science Foundation of China,No.30771140,31070952 and U1204311
文摘Astrocytes are intimately involved in the formation and development of retinal vessels. Astrocyte dysfunction is a major cause of blood-retinal barrier injury and other retinal vascular diseases. In this study, the development of the retinal vascular system and the formation of the blood-ret-inal barrier in mice were investigated using immunolfuorescence staining, gelatin-ink perfusion, and transmission electron microscopy. The results showed that the retinal vascular system of mice develops from the optic disc after birth, and radiates out gradually to cover the entire retina, taking the papilla optica as the center. First, the superifcial vasculature is formed on the inner retinal layer;then, the vasculature extends into the inner and outer edges of the retinal inner nuclear layer, forming the deep vasculature that is parallel to the superifcial vasculature. The blood-retinal barrier is mainly composed of endothelium, basal lamina and the end-feet of astrocytes, which become mature during mouse development. Initially, the naive endothelial cells were immature with few organelles and many microvilli. The basal lamina was uniform in thickness, and the glial end-feet surrounded the outer basal lamina incompletely. In the end, the blood-retinal barrier matures with smooth endothelia connected through tight junctions, rela-tively thin and even basal lamina, and relatively thin glial cell end-feet. These ifndings indicate that the development of the vasculature in the retina follows the rules of“center to periphery”and“superifcial layer to deep layers”. Its development and maturation are spatially and tempo-rally consistent with the functional performance of retinal neurons and photosensitivity. The blood-retinal barrier gradually becomes mature via the process of interactions between astro-cytes and blood vessel cells.
基金Supported by the Science and Technology Planning Project of Guangdong Province(No.201607010386)the Science and Technology Planning Project of Guangzhou(No.201504290959196)。
文摘AIM: To investigate the role of moesin and its underlying signal transduction in retinal vascular damage induced by retinal ischemia-reperfusion(RIR) insult.METHODS: C57 BL/6 mice were subjected to continued ischemia for 45 min, followed by blood reperfusion. The expression and phosphorylation of moesin in retinal vessels were detected by immunohistochemistry and Western blotting. The inner blood-retinal barrier was evaluated using FITCdextran leakage assay on whole-mount retina. Further studies were conducted to explore the effects of p38 mitogen-activated protein kinase(MAPK) pathway on the involvement of moesin in RIR-evoked retinal vascular hyperpermeability response. RESULTS: It revealed that RIR induced moesin phosphorylation in a time-dependent manner after reperfusion. The phosphorylation of moesin was alleviated by inhibitions of p38 MAPK, while this treatment also ameliorated the dysfunction of inner blood-retinal barrier. CONCLUSION: The results suggest that moesin is involved in RIR-evoked retinal vascular endothelial dysfunction and the phosphorylation of moesin is triggered via p38 MAPK activation.
基金Supported by National Natural Science Foundation of China(No.81000388)Health and Family Planning Commission of Hunan Province(No.132015-016)Natural Science Foundation of Hunan Province(No.12JJ3120)
文摘AIM: To evaluate the therapeutic effect of fluorofenidone on disrupted blood-retinal barrier in the diabetic mice and uncover its underlying mechanism. METHODS: db/db mice were randomly chosen for treatment with daily doses of fluorofenidone or placebo at 5-week-old, treatment continued until mice reach 24-week- old. Then, expression of transcriptiona factor insulin gene enhancer binding protein-1 (Islet-I) and vascular endothelial growth factor (VEGF) in murine retinas were evaluated. Retinal vascular permeability was assessed by examining the level of albumin in db/db murine retinas. Furthermore, the retinal vessel tight junction was estimated by checking the level of occludin in the murine retinal tissues. RESULTS: After occurrence of diabetic retinopthy in db/ db mice, expressions of transcritpional factor Islet-1 was found to be upregulated in db/db murine retinas compared with non-diabetic controls. Similar to expression pattern of Islet-l, VEGF were also demonstrated to be increased in retinas of db/db mice, which was accompanied by increased retinal vascular leakage and decreased tight junction protein level. Systemetic administration of fluorofenidone repaired broken retinal vascular tight junction by restoring occludin expression in db/db retinal tissue. Consequently, retinal vascular premeability were indicated to be reduced by examining the transudative albumin level in diabetic retinal tissues. Both Islet-1 and VEGF expression were inhibited in the retinas of db/db mice after treatment with fluorofenidone. CONCLUSION: Fluorofenidone significantly protectes retinal tight junction and reduces retinal vascular leakage. The phenomenon can be partially attributed to reducing overexpression of Islet-1 and VEGF in diabetic retinal tissues.
基金Supported by the National Natural Science(No.81660217)National College Students Innovation and Entrepreneurship Training Program Project (No.201911810004)。
文摘AIM: To clarify the role of inducible nitric oxide synthase(i NOS) in blood-retinal barrier(BRB) injury after acute high intraocular pressure(IOP) in rats.METHODS: Forty-two Sprague-Dawley(SD) rats were randomized into 7 groups [control(Cont), 3, 6, 12, 24, 48, and 72 h, n=6]. Except Cont group, other groups’ retina tissue was obtained at corresponding time points after a model of acute high IOP have been established in rats. The expression of i NOS and tight junction protein zonula occludens(ZO)-1 was detected by Western blotting. Evans blue(EB;3%) was injected into the great saphenous vein to detect the leakage of EB by spectrophotometer. Nine rats were divided into Cont, 6 h, 12 h groups, the expression of i NOS was localized by immunofluorescence. In order to verify the role of i NOS in the damage to BRB, thirty-six rats were randomly divided into 4 groups [Cont, Cont+inhibitor(Inh), 6 h and 6 h+Inh, n=9]. After treatment with the i NOSspecific inhibitor 1400 W, the expression of i NOS and ZO-1 and the leakage of BRB were detected again.RESULTS: The immunofluorescence results showed that the expression of i NOS was observed in the Cont group and 6 h group, but not in the 12 h group. i NOS was mainly expressed in the retinal nerve fiber layer, ganglion cell layer and inner nuclear layer and that it did not colocalize with the retinal ganglion cell marker Neu N but was co-expressed with the vascular endothelial cell marker CD31. Western blotting showed that in the early period(3 h, 6 h) after acute high IOP, the expression of i NOS was upregulated, then the down-regulation of i NOS were tested in the follow-up timing spots. ZO-1 expression showed a continuous downregulation after 6 h. The quantitative results for EB showed that the amount of EB leakage began to increase at 3 h after acute high IOP. At 6 h, the leakage of EB was lower, but at 12 h, the leakage of EB was highest, after which it gradually recovered but remained higher than that in the Cont group. The expression of i NOS was down-regulated after 1400 W treatment. ZO-1 expression was not significantly changed in the Cont+Inh group and the 6 h group, and significantly down-regulated in the 6 h+Inh group, and the leakage of EB was significantly increased after 1400 W treatment.CONCLUSION: These results suggest that the upregulation of i NOS expression in the early stage after acute high IOP may have a protective effect on BRB injury.
基金Supported by the National Natural Science Foundation of China(No.81400407)Natural Science Foundation of Anhui Province(No.1408085QH159)。
文摘AIM:To observe the effects of the inhibition of NADPH oxidase 4(NOX4)expression on the retinal vascular barriers and visual function after retinal detachment(RD).METHODS:RD model was established 3 wk after adenoassocianed virus vector injection.The retinal tissue was harvested 3 d after RD,and the death of retinal vascular endothelial cells and photoreceptors was observed using electron microscopy.The NOX4 expression was detected by Western blot.Confocal microscopy was used to observe a retinal patch that had been perfused with Evans blue.A modified water maze test was used to detect the time required to find the platform on the water surface.The visual function of the rats was evaluated and reactive oxygen species(ROS)expression was detected by a fluorescence microplate reader.RESULTS:The retinal patch showed that NOX4 interference significantly reduced the destruction of the tight junctions between the retinal endothelium of RD rats and reduced leakage.Western blotting showed decreased expression of the NOX4 protein and decreased expression of ROS in retinal tissue;the Morris water maze test results showed that NOX4 interference significantly decreased the escape latency of the rats.CONCLUSION:NOX4 interference reduces the production of ROS in retinal vascular endothelial cells after experimental RD,thereby protecting the blood-retinal barrier and protecting visual function.
基金Supported by the National Natural Science Foundation of China(No.81660217)Youth Foundation of the First Affiliated Hospital of Hainan Medical University(No.HYYFYPY201922)。
文摘AIM:To elucidate the role of vascular endothelial growth factor-165b(VEGF-165b)in blood-retinal barrier(BRB)injury in the rat acute glaucoma model.METHODS:In this study,the rat acute high intraocular pressure(HIOP)model was established before and after intravitreous injection of anti-VEGF-165b antibody.The expression of VEGF-165b and zonula occludens-1(ZO-1)in rat retina was detected by double immunofluorescence staining and Western blotting,and the breakdown of BRB was detected by Evans blue(EB)dye.RESULTS:The intact retina of rats expressed VEGF-165b and ZO-1 protein,which were mainly located in the retinal ganglion cell layer and the inner nuclear layer and were both co-expressed with vascular endothelial cell markers CD31.After acute HIOP,the expression of VEGF-165b was up-regulated;the expression of ZO-1 was down-regulated at 12h and then recovered at 3d;EB leakage increased,peaking at 12h.After intravitreous injection of anti-VEGF-165b antibody,the expression of VEGF-165b protein was no significantly changed;and the down-regulation of the expression of ZO-1 was more obvious;EB leakage became more serious,peaking at 3d.EB analysis also showed that EB leakage in the peripheral retina was greater than that in the central retina.CONCLUSION:The endogenous VEGF-165b protein may protect the BRB from acute HIOP by regulating the expression of ZO-1.The differential destruction of BRB after acute HIOP may be related to the selective loss of retinal ganglion cells.
基金supported by the National Natural Science Foundation of China(NSFC No.82104101)Jiangxi Provincial Natural Science Foundation,China(Grant No.20212BAB216003)+1 种基金the Project of Gannan Medical University(No.ZD201903)Ph.D.Start-up Fund of Gannan Medical University(QD201908).
文摘The blood-brain barrier(BBB)is an essential component in regulating and maintaining the homeostatic microenvironment of the central nervous system(CNS).During the occurrence and development of glioblastoma(GBM),BBB is pathologically destroyed with a marked increase in permeability.Due to the obstruction of the BBB,current strategies for GBM therapeutics still obtain a meager success rate and may lead to systemic toxicity.Moreover,chemotherapy could promote pathological BBB functional restoration,which results in significantly reduced intracerebral transport of therapeutic agents during multiple administrations of GBM and the eventual failure of GBM chemotherapy.The effective delivery of intracerebral drugs still faces severe challenges.However,strategies that regulate the pathological BBB to enhance the transport of therapeutic agents across the barrier may provide new opportunities for the effective and safe treatment of GBM.This article reviews the structure and function of BBB in physiological states,the mechanisms underlying BBB pathological fenestration during the development of GBM,and the therapeutic strategies of GBM based on BBB intervention and medicinal drugs transporting across the BBB.
基金supported in part by the National Basic Research Program of China,No.81300766(to XSM)the Cultivation and Innovation Fund from the First Affiliated Hospital of Jinan University,China,No.802168(to XSM)+2 种基金Hygiene&Health Appropriated Technology and Promoting Project of Guangdong Province of China,No.201905270933056876(to XSM)the fund of Leading Talents of Guangdong Province of China,No.87014002(to KFS)a grant from Ningxia Key Research and Development Program,and Programme of Introducing Talents of Discipline to Universities of China,No.B14036(to KFS)。
文摘Our previous study verified the protective effects of Lycium barbarum polysaccharides(LBP)on retinal neurons and blood vessels in acute ocular hypertension(AOH)mice.To investigate the effect of LBP on the reactivity of retinal glial cells,an AOH mouse model was established in one eye by maintaining ocular hypertension of 90 mm Hg for 60 minutes.Either LBP solution(1 mg/kg)or phosphate-buffered saline was administrated to the mice by gavage daily,starting 7 days before the AOH insult and continuing until the mice were sacrificed for specimen collection on day 4 post-insult.After AOH insult,increased numbers of astrocytes and microglia were observed,together with decreased expression of the following glial cell biomarkers in the retinal ganglion cells of AOH mice:glial fibrillary acidic protein,glutamine synthetase,aquaporin-4,S-100 proteins,ionized calcium-binding adaptor molecule 1,amyloid precursor protein and receptor of advanced glycosylation end-products.After intervention with LBP,the above changes were significantly reduced.Remarkably,morphological remodeling of blood vessel-associated retinal astrocytes,marked by glial fibrillary acidic protein,was also observed.These results,taken together,suggest that LBP regulated the production of amyloid-βand expression of receptor of advanced glycosylation end-products,as well as mediating the activity of retinal glial cells,which may lead to the promotion of better maintenance of the blood-retinal barrier and improved neuronal survival in AOH insult.This study was approved by the Committee for the Use of Live Animals in Teaching and Research(approval No.CULTRA-#1664-08).
基金supported by the Science and Technology Development Fund (Macao SAR)(120015/2019/ASC,0023/2020/AFJ,0035/2020/AGJ)the University of Macao Research Grant (MYRG2022-00248-ICMS)(all to MPMH)。
文摘Blood-brain barrier disruption occurs in the early stages of Alzheimer’s disease.Recent studies indicate a link between blood-brain barrier dysfunction and cognitive decline and might accelerate Alzheimer’s disease progression.Astrocytes are the most abundant glial cells in the central nervous system with important roles in the structural and functional maintenance of the blood-brain barrier.For example,astrocytic cove rage around endothelial cells with perivascular endfeet and secretion of homeostatic soluble factors are two major underlying mechanisms of astrocytic physiological functions.Astrocyte activation is often observed in Alzheimer’s disease patients,with astrocytes expressing a high level of glial fibrillary acid protein detected around amyloid-beta plaque with the elevated phagocytic ability for amyloid-beta.Structural alte rations in Alzheimer’s disease astrocytes including swollen endfeet,somata shrinkage and possess loss contribute to disruption in vascular integrity at capillary and arte rioles levels.In addition,Alzheimer’s disease astrocytes are skewed into proinflammatory and oxidative profiles with increased secretions of vasoactive mediators inducing endothelial junction disruption and immune cell infiltration.In this review,we summarize the findings of existing literature on the relevance of astrocyte alte ration in response to amyloid pathology in the context of blood-brain barrier dysfunction.First,we briefly describe the physiological roles of astrocytes in blood-brain barrier maintenance.Then,we review the clinical evidence of astrocyte pathology in Alzheimer’s disease patients and the preclinical evidence in animal and cellular models.We further discuss the structural changes of blood-brain barrier that correlates with Alzheimer’s disease astrocyte.Finally,we evaluate the roles of soluble factors secreted by Alzheimer’s disease astrocytes,providing potential molecular mechanisms underlying blood-brain barrier modulation.We conclude with a perspective on investigating the therapeutic potential of targeting astrocytes for blood-brain barrier protection in Alzheimer’s disease.
基金Supported by Fujian Provincial Health and Family Planning Commission(No.2014-ZQN-ZD-16)
文摘AIM: To clarify the mechanism of infliximab treatment in diabetic macular edema (DME) and to provide a new alternative therapy for DME. METHODS: Rats were randomly divided into the control group, the model group and the infliximab treatment group. A diabetic rat model was created. The concentration of TNF-α in the vitreous body was detected by ELISA. The expressions of B-Raf, p38, claudin-1 and occludin in the retina were detected by Western blot. The integrity of the blood retinal barrier (BRB) was measured using Evan's blue as a tracer. RESULTS: After three months and six months of the diabetes model, the vitreous TNF-α level in the model group was higher than that of the control group. It was also higher in treated group than that of the control group but was lower than that of the model group. The differences among the three groups were statistically significant (at 3mo, F=857.098, P〈0.001; 6mo, F=1261.897, P〈0.001). The retina B-Raf and p38 levels in the model group were higher than that of the control group. They were also higher in treated group than that of the control group but were lower than that of the model group. The differences among the three groups were statistically significant (B-Raf at 3mo, F=106.596, P〈0.001 and at 6mo, F=200.681, P〈0.001; p38 at 3mo, F=41.662, P〈0.001 and at 6mo, F=67.979, P〈0.001). The retina claudin-1 and occludin levels in the model group were lower than that of the control group. They were also lower in treated group than that of the control group but were higher than that of the model group. The differences among three groups were statistically significant (claudin-1 at3mo, F=-139.088, P〈0.001 and at 6mo, F=128.415, P〈0.001; occludin at 3mo, F=-92.733, P〈0.001 and at 6mo, F--104.478, P〈0.001). The retinal Evans blue leakage in the model group was higher than that of the control group. It was also higher in treated group than that of the control group but was lower than that of the model group. The differences among the three groups were statistically significant (at 3mo, F=-447.946, P〈0.001; at 6mo, F'=-1610.732, P〈0.001). CONCLUSION: In-α diabetic rat model, infliximab may relieve TNF-α induced BRB breakdown via the B-Raf and p38 signaling pathway.
基金grants from the Major Project of National Natural Science Foundation of China(NSFC)-Guangdong Province Joint Fund(No.3030902113080)the Science and Technology Planning Project of Guangdong Province(No.303090100502050-18)the Guangzhou Science and Technology Plan Project(Nos.201803040020 and 201903010065)。
文摘Clinical ophthalmologists consider each retinal disease as a completely unique entity.However,various retinal diseases,such as uveitis,age-related macular degeneration,diabetic retinopathy,and primary open-angle glaucoma,share a number of common pathogenetic pathways.Whether a retinal disease initiates from direct injury to the blood-retinal barrier(BRB)or a defect/injury to retinal neurons or glia that impairs the BRB secondarily,the BRB is a pivotal point in determining the prognosis as self-limiting and recovering,or developing and progressing to a clinical phenotype.The present review summarizes our current knowledge on the physiology and cellular and molecular pathology of the BRB,which underlies its pivotal role in the initiation and development of common retinal diseases.