Experimental study on the treatment of rabbit corneal melting after alkali burn with Collagen cross-linking

AIM: To evaluate the effect of Collagen cross-linking on the prevention of melting in rabbit corneas after alkali burn. METHODS: Twenty New Zealand white rabbits were randomly divided into model control group and collagen cross-linking treatment group. The second group of rabbits received collagen cross linked treatment. Both groups were applied with antibiotic eye drops to prevent infection. The corneas were evaluated for melting, opacity, pathological and immunohistochemistry, record the changes when 28 days after the animals were killed. RESULTS: In the control group, 6 out of 8 rabbits showed corneal melting after injury (14 +/- 4) days, while two corneal perforated. In collagen cross-linking treatment group, one rabbit showed corneal melting after injury 23 days, without corneal perforation; corneal dissolution rate between the two groups was significantly different (P <0.05). Pathological examination suggested that in the treatment group, mild corneal edema, mild damage to collagen fibers, inflammatory cell infiltration was significantly less than the control group. Immunohistochemistry showed that corneal collagen fibers arranged in neat rows in the control group. CONCLUSION: Collagen cross-linking treatment not only can prevent and delay the corneal melting after alkali burn, but also can reduce the destruction of corneal collagen fibers and infiltration of inflammatory cells in the corneal tissue.

Effects of AMD3100 subconjunctival injection on alkali burn induced corneal neovascularization in mice

AIM: To investigate the therapeutic effects of local and systemic administration of AMD3100 for alkali burn induced corneal neovascularization (CNV) in mice. METHODS: CNV was induced in vivo by alkaline burn of cornea in C57BL/6 mice. AMD3100 was administrated topically by subconjunctival injection or systemically by intraperitoneal injection for 7 days; balanced salt solution was administrated topically or systemically as a control respectively. Inflammatory index was evaluated by slit-lamp biomicroscopy and inflammatory cells infiltrated to cornea tissue were detected by histologic analysis at multiple time points. CNV was compared between the local and systemic treated mice 2 weeks after alkali burn, as quantified by CD34 immunostaining. Fluorescence-Activated Cell Sorter Analysis was used to investigate the mobilizing effects of EPC in mice after subconjunctival injected or intraperitoneal injected AMD3100. Immunohistochemistry was used to detect the expression of endothelial progenitor cells (EPC) marker proteins VEGFR2 and CD34. RESULTS: Three days after alkali burn, infiltration of inflammatory cells was found in corneal tissue. At the first 7 days of local injection group, the number of inflammatory cells was significantly lower than that in systemic injection group. CNV could be seen at the 7(th) day, and at the 14(th) day reached the peak, then started to decrease. The number of CNV in the subconjunctival injection group was 7.57 +/- 1.26 per 0.034mm(2), compared to a number of 14.87 +/- 2.21 per 0.034mm(2) in the control group (P<0.05). On the contrary, the number of CNV in the intraperitoneal injection group was a little higher than that in the control group, 16.34 +/- 1.53 per 0.034mm(2) vs 13.26 +/- 1.87 per 0.034mm(2). The research also showed that intraperitoneally, but not subconjunctivally injected AMD3100 could mobilize EPC. On the other hand, subconjunctival, but not intraperitoneally injected AMD3100 could reduce the expression of EPC marker proteins. CONCLUSION: In mice locally administrated AMD3100 can reduce the number of alkali burn induced CNV. The number of inflammatory cells and inflammatory responses in corneal tissue.

Research on mouse model of grade Ⅱ corneal alkali burn

AIM： To choose appropriate concentration of sodium hydroxide（Na OH） solution to establish a stable and consistent corneal alkali burn mouse model in grade II.·METHODS： The mice（n =60） were randomly divided into four groups and 15 mice each group. Corneal alkali burns were induced by placing circle filter paper soaked with Na OH solutions on the right central cornea for 30 s.The concentrations of Na OH solutions of groups A, B, C,and D were 0.1 mol/L, 0.15 mol/L, 0.2 mol/L, and 1.0 mol/L respectively. Then these corneas were irrigated with 20 m L physiological saline（0.9% Na Cl）. On day 7 postburn, slit lamp microscope was used to observe corneal opacity,corneal epithelial sodium fluorescein staining positive rate, incidence of corneal ulcer and corneal neovascularization, meanwhile pictures of the anterior eyes were taken. Cirrus spectral domain optical coherence tomography was used to scan cornea to observe corneal epithelial defect and corneal ulcer.·RESULTS： Corneal opacity scores（ x ±s） were not significantly different between the group A and group B（P =0.097）. Incidence of corneal ulcer in group B was significantly higher than that in group A（P =0.035）.Incidence of corneal ulcer and perforation rate in group B was lower than that in group C. Groups C and D had corneal neovascularization, and incidence of corneal neovascularization in group D was significantly higher than that in group C（P =0.000）.·CONCLUSION： Using 0.15 mol/L Na OH can establish grade II mouse model of corneal alkali burns.

Efficacy of the nucleotide-binding oligomerization domain 1 inhibitor Nodinhibit-1 on corneal alkali burns in rats

AIM: To evaluate the therapeutic effect of Nodinhibit-1 on alkali-burn-induced corneal neovascularization (CNV) and inflammation. The nucleotide-binding oligomerzation domain 1 (NOD1) is a potent angiogenic gene. METHODS: The alkali -burned rat corneas (32 right eyes) were treated with eye drops containing Nodinhibit-1 or phosphate buffered solution (PBS, pH 7.4) only, four times per day. CNV and inflammation were monitored using slit lamp microscopy, and the area of CNV was measured by formula. Vascular endothelial growth factor (VEGF) and pigment epithelium -derived factor (PEDF) was determined by Western blot analysis. The TUNEL assay was used to assess the corneal apoptosis cells. RESULTS: Alkali-burn-induced progressive CNV and inflammation in the cornea. After treatment for 7d and 14d, there were statistically significant differences in the CNV areas and inflammatory index on that between two group(P<0.05, respectively). Epithelial defect quantification showed a significant difference between the two groups at days 4 and 7 after the alkali burns (P<0.05). The apoptotic. cells on days 1, 4, and 7 between the two groups showed significant differences at all time points (P<0.05, respectively). Compared to that in control group, the protein level of VEGF expression was significantly reduced whereas the PEDF expression was increase in the Nodinhibit-1 groups on day 14(P<0.05, respectively). CONCLUSION: Topical application of 10.0 mu g/mL Nodinhibit -1 may have potential effect for the alkali burn -induced CNV and inflammation. The effect of Nodinhibit -1 on CNV may be by regulation the equilibrium of VEGF and PEDF in the wounded cornea.

Effect of amnion membrane transplantation on corneal neovascularization in 10 patients with alkali burn

By observing clinical cases, we studied the curative effect of amnion membrane transplantation on decreasing corneal neovascularization (CNV). It was a non-randomized retrospective case-control study. Among 17 cases (21 eyes) of third-degree alkali burns from 2007 to 2010, 10 cases (12 eyes) were performed with amnion membrane transplantation operation, and others were not. Amnion membrane transplantation was performed at the 3rd day after burn in the treatment group. Areas of CNV in double groups were measured at the 14th day and 60th day after burn. Area of CNV in the treatment group was (66.207±7.251)mm2 at the 14th day after burn, and was 18.27% lower than that in the control group. Area of CNV in the treatment group was (120.046±13.812)mm2 at the 60th day after burn, and was 11.35% lower than that in the control group. There was both statistical significance (P<0.05). Amnion membrane transplantation operation can inhibit the growth of corneal neovascularization induced by alkali burn.

Inhibitory effect of polysulfated heparin endostatin on alkali burn induced corneal neovascularization in rabbits

AIM: To investigate anti-angiogenic effects of polysulfated heparin endostatin(PSH-ES) on alkali burn induced corneal neovascularization(NV) in rabbits.METHODS: An alkali burn was made on rabbit corneas to induce corneal NV in the right eye of 24 rabbits. One day after burn creation, a 0.2 m L subconjunctival injection of 50 μg/m L PSH-ES, 50 μg/m L recombinant endostatin(ES), or normal saline was administered every other day for a total of 14d(7 injections). Histology and immunohistochemisty were used to examine corneas.Corneal NV growth was evaluated as microvessel quantity and corneal vascular endothelial growth factor(VEGF)expression was measured by immunohistochemical assay.RESULTS: Subconjunctival injection of ES and PSHES resulted in significant corneal NV suppression, but PSH-ES had a more powerful anti-angiogenic effect than ES. Mean VEGF concentration in PSH-ES treated corneas was significantly lower than in ES treated and saline treated corneas. Histological examination showed that corneas treated with either PSH-ES or ES had significantly fewer microvessels than eyes treated with saline. Additionally corneas treated with PSH-ES had significantly fewer microvessels than corneas treated with ES.CONCLUSION: Both PSH-ES and recombinant ES effectively inhibit corneal NV induced by alkali burn.However, PSH-ES is a more powerful anti-angiogenic agent than ES. This research has the potential to provide a new treatment option for preventing and treating corneal NV.

Emodin suppresses alkali burn-induced corneal inflammation and neovascularization by the vascular endothelial growth factor receptor 2 signaling pathway

OBJECTIVE:To investigate the effects of emodin on alkali burn-induced corneal inflammation and neovascularization.METHODS:The ability of emodin to target vascular endothelial growth factor receptor 2(VEGFR2)was predicted by molecular docking.The effects of emodin on the invasion,migration,and proliferation of human umbilical vein endothelial cells(HUVEC)were determined by cell counting kit-8,Transwell,and tube formation assays.Analysis of apoptosis was performed by flow cytometry.CD31 levels were examined by immunofluorescence.The abundance and phosphorylation state of VEGFR2,protein kinase B(Akt),signal transducer and activator of transcription 3(STAT3),and P38 were examined by immunoblot analysis.Corneal alkali burn was performed on 40 mice.Animals were divided randomly into two groups,and the alkali-burned eyes were then treated with drops of either 10μM emodin or phosphate buffered saline(PBS)four times a day.Slitlamp microscopy was used to evaluate inflammation and corneal neovascularization(CNV)in all eyes on Days 0,7,10,and 14.The mice were killed humanely 14 d after the alkali burn,and their corneas were removed and preserved at-80℃ until histological study or protein extraction.RESULTS:Molecular docking confirmed that emodin was able to target VEGFR2.The findings revealed that emodin decreased the invasion,migration,angiogenesis,and proliferation of HUVEC in a dose-dependent manner.In mice,emodin suppressed corneal inflammatory cell infiltration and inhibited the development of corneal neovascularization induced by alkali burn.Compared to those of the PBS-treated group,lower VEGFR2 expression and CD31 levels were found in the emodintreated group.Emodin dramatically decreased the expression of VEGFR2,p-VEGFR2,p-Akt,p-STAT3,and p-P38 in VEGF-treated HUVEC.CONCLUSION:This study provides a new avenue for evaluating the molecular mechanisms underlying corneal inflammation and neovascularization.Emodin might be a promising new therapeutic option for corneal alkali burns.

Effect of doxycycline intervention on the apoptosis as well as the IL-1, TNF-α and HIF-1α expression in cornea and aqueous humor in rats with corneal alkali burn

Objective:To study the effect of doxycycline intervention on the apoptosis as well as the IL-1, TNF-α and HIF-1α expression in cornea and aqueous humor in rats with corneal alkali burn.Methods: Male SD rats were selected as experimental animals and randomly divided into control group, alkali burn group and doxycycline group, corneal alkali burn models were established by sodium hydroxide eye drop and then they received doxycycline eye drops intervention. The expression of apoptosis molecules, inflammatory response cytokines and angiogenesis moleculesin the cornea as well as the expression of inflammatory response cytokines and angiogenesis molecules in aqueous humor were detected 14 and 28 d after model establishment.Results: 14 and 28 d after model establishment, Bcl-2 and PEDF protein expression in cornea tissue of alkali burn group were significantly lower than those of control group while Caspase-3, Caspase-8, Caspase-9, IL-1, TNF-α, HIF-1α and VEGF protein expression were significantly higher than those of control group;Bcl-2 and PEDF protein expression in cornea tissue of doxycycline group were significantly higher than those of alkali burn group while Caspase-3, Caspase-8, Caspase-9, IL-1, TNF-α, HIF-1α and VEGF protein expression were significantly lower than those of alkali burn group.Conclusion: Doxycycline for corneal alkali burn intervention can inhibit the apoptosis, inflammatory response and angiogenesis.

LRG1 promotes corneal angiogenesis and lymphangiogenesis in a corneal alkali burn mouse model

AIM:To investigate the potential effect and mechanism of leucine-richα-2-glycoprotein-1(LRG1)on corneal angiogenesis and lymphangiogenesis.METHODS:Corneal neovascularization and lymphatics were induced by establishing alkali burn mouse model.Immunofluorescence staining was performed to detect the location of LRG1 in cornea tissues and to verify the source of LRG1-positive cells.Corneal whole-mount staining for CD31(a panendothelial cell marker)and lymphatic endothelial hyluronan receptor-1(LYVE-1;lymphatic marker)was performed to detect the growth of blood and lymphatic vessels after local application of exogenous LRG1 protein or LRG1 si RNA.In addition,expressions of the proangiogenic vascular endothelial growth factor(VEGF)related proteins were detected using Western blot analysis.RESULTS:LRG1 was dramatically increased in alkali burned corneal stroma in both the limbal and central areas.LRG1-positive cells in the corneal stroma were mainly derived from Vimentin-positive cells.Local application ofexogenous LRG1 protein not only aggravated angiogenesis but also lymphangiogenesis significantly(P<0.01).LRG1 group upregulated the levels of VEGF and the vascular endothelial growth factor receptor(VEGFR)family when compared with the phosphate-buffered saline(PBS)control group.We also found that LRG1-specific si RNA could suppress corneal angiogenesis and lymphangiogenesis when compared with the scramble si RNA-treated group(P<0.01).CONCLUSION:LRG1 can facilitate corneal angiogenesis and lymphangiogenesis through heightening the stromal expression of VEGF-A,B,C,D and VEGFR-1,2,3;LRG1-specific si RNA can suppress corneal angiogenesis and lymphangiogenesis in corneal alkali burn mice.

A Rational Design of Metal–Organic Framework Nanozyme with High‑Performance Copper Active Centers for Alleviating Chemical Corneal Burns

Metal–organic frameworks(MOFs)have attracted significant research interest in biomimetic catalysis.However,the modulation of the activity of MOFs by precisely tuning the coordination of metal nodes is still a significant challenge.Inspired by metalloenzymes with well-defined coordination structures,a series of MOFs containing halogen-coordinated copper nodes(Cu-X MOFs,X=Cl,Br,I)are employed to elucidate their structure–activity relationship.Intriguingly,experimental and theoretical results strongly support that precisely tuning the coordination of halogen atoms directly regulates the enzyme-like activities of Cu-X MOFs by influencing the spatial configuration and electronic structure of the Cu active center.The optimal Cu–Cl MOF exhibits excellent superoxide dismutase-like activity with a specific activity one order of magnitude higher than the reported Cu-based nanozymes.More importantly,by performing enzyme-mimicking catalysis,the Cu–Cl MOF nanozyme can significantly scavenge reactive oxygen species and alleviate oxidative stress,thus effectively relieving ocular chemical burns.Mechanistically,the antioxidant and antiapoptotic properties of Cu–Cl MOF are achieved by regulating the NRF2 and JNK or P38 MAPK pathways.Our work provides a novel way to refine MOF nanozymes by directly engineering the coordination microenvironment and,more significantly,demonstrating their potential therapeutic effect in ophthalmic disease.

Observation on ultrastructure and histopathology of cornea following femtosecond laser-assisted deep lamellar keratoplasty for acute corneal alkaline burns

AIM： To demonstrate the changes in ultrastructure and histopathology of the cornea in acute corneal alkaline burns after femtosecond laser-assisted deep lamellar keratoplasty.·METHODS： The New Zealand white rabbits treated with alkaline corneal burn were randomized into two groups,Group A（16 eyes） with femtosecond laser-assisted deep lamellar keratoplasty 24 h after burn and Group B（16 eyes）without keratoplasty as controls. All eyes were evaluated with transmission electron microscopy（TEM） at 1, 2, 3,and 4wk follow-up, then all corneas were tested by hematoxylin and eosin staining histology.· RESULTS： The corneal grafts in Group A were transparent, while those in Group B showed corneal stromal edema and loosely arranged collagen fibers. One week after treatment, TEM revealed the intercellular desmosomes in the epithelial layers and intact non-dissolving nuclei in Group A. At week 4, the center of the corneas in Group A was transparent with regularly arranged collagen fibers and fibroblasts in the stroma. In Group B, squamous cells were observed on the corneal surface and some epithelial cells were detached.· CONCLUSION： Femtosecond laser-assisted deep lamellar keratoplasty can suppress inflammatory responses, prevent toxic substance-induced injury to the corneal endothelium and inner tissues with quicker recovery and better visual outcomes.

Hydrogen promotes the activation of Cu, Zn superoxide dismutase in a rat corneal alkali-burn model

AIM: To investigate the effects of hydrogen(H2) on Cu, Zn superoxide dismutase(SOD1) activation in a rat model of corneal alkali burn. METHODS: In each rat, one cornea was subjected to alkali exposure. Physiological saline(saline group) or H2-dissolved saline(H2 group) was instilled continuously on the cornea for 5 min before and after alkali exposure. Inflammatory cells, neovascularization, and cytoplasmic SOD1 levels were evaluated immunohistochemically in enucleated eyes from both groups. Three-dimensional ultrastructural tissue changes in the eyes were analyzed using low-vacuum scanning electron microscopy.RESULTS: The numbers of both inflammatory and vascular endothelial cells were significantly reduced in the corneas of the H2 group(P<0.01). Furthermore, H2 treatment increased both cytoplasmic SOD1 levels(P<0.01) and activity in corneal epithelial cells(P<0.01). Notably, the SOD1 activity level in the H2 group was approximately 2.5-fold greater than that in the saline group.CONCLUSION: H2 treatment suppresses inflammation and neovascularization in the injured cornea and indirectly suppresses oxidative insult to the cornea by upregulating the SOD1 enzyme protein level and activity.

The Effect of Fibronectin on Re-epithelialization of Rabbits Cornea after Alkali Burn

The authors found experimentally that (1) fibronectin enhanced the healing of rabbit corneal epithelium after alkali burn and prevented the secondary breakdown; (2) it rapidly deposited on the denuded basement membrane to disappear as epithelial cells slided over, and (3) ultrastructurally, the neighbouring epithelial cells became flattened, with filopodia at the advancing edge, and extended to the wounded areas at 24 hours after the burn. However, the epithelial defects recurred 72 hours after the burn...

Effect of nintedanib thermo-sensitive hydrogel on neovascularization in alkali burn rat model

AIM:To investigate the effects of nintedanib thermo-sensitive hydrogel(NTH)on neovascularization and related markers in corneal alkali burns of Wistar rats.METHODS:NTH was prepared by grinding,and its phase-transition temperature was determined.Thirty specific-pathogen-free Wistar rats served as a model of corneal alkali burn in the right eye were randomly divided into 3 groups(n=10,each):model group treated with 0.9%saline once a day,NTH group with 0.2%nintedanib b.i.d,and dexamethasone group with dexamethasone ointment once a day.The left eye of rats served as the controls.The corneal transparency was observed under a slit-lamp microscope,and the area of neovascularization was calculated.On day 7,the rats were sacrificed,and the cornea was removed and embedded with paraffin,then stained with hematoxylin一eosin,and the expression of vascular endothelial growth factor receptor 2(VEGFR-2)and CD31 in the corneal tissues of each group was detected by immunofluorescence.RESULTS:The phase-transition temperature ofnintedanib obtained by grinding was 37℃after adding artificial tears.The results of the alkali burn model indicated that the growth rate of neovascularization in the NTH group was slower than that in the model group,and the neovascularization area was significantly smaller than that in the model group(P<0.05).Moreover,CD31 and VEGFR-2 expression levels in the NTH group were significantly lower than those in the model group.CONCLUSION:NTH becomes colloidal at body temperature,which is beneficial for releasing the drug slowly and can significantly inhibit the neovascularization of corneal induced by alkali burn in rats.

Evaluation of immersion 20 MHz B-scan ultrasonography in observing lens in the alkali burn eyes

·AIM: To evaluate the accuracy of 20 MHz immersion Bscan ultrasonography in observing lens and to investigate the value of this noninvasive preoperative diagnosis method in alkali burn eyes.·METHODS: It was a comparative study. Fifty-six cases(56 eyes) of alkali burn eyes were examined by ultrasound biomicroscopy(UBM) and immersion 20 MHz B-scan ultrasonography from June 2011 to April 2013,the images were analyzed, and the ultrasonographic diagnosis compared with the operation results.·RESULTS: In 56 alkali burn eyes examined by UBM, the lens were not detected in 16 eyes; the IOL could be detected in 2 eyes; the anterior lens capsule surface or/and the front lens could be detected in 18 eyes, and lens opacification in 3 eyes of them; suspected abnormal lens were detected in the other 20 eyes. In all the same eyes examined by immersion 20 MHz B-scan ultrasonography,the lens were not detected in 16 eyes; the IOL could be detected in 2 eyes; 24 abnormal lens(opacity, lens expansion, shrinkage) and 14 normal lens were found.Compared with the intraoperative findings, the diagnostic accordance rate of the immersion 20 MHz B-scan appearance of lens was 100%(56/56), which was significantly higher than examined by UBM 57.14%(32/56)(χ2=30.55, P =0.0000).·CONCLUSION: Immersion 20 MHz B-scan ultrasonography can observe the lens accurately in alkali burn eyes. It has important clinical value to combine with UBM in eyes of alkali burn.

Rescue of human corneal epithelial cells after alkaline insult using renalase derived peptide, RP-220

AIM:To study the effect of renalase peptide,RP-220,on cell viability of human corneal epithelial cells after alkali insult.METHODS:A dose-response relationship between cell viability and exposure to NaOH solution were characterized using cultured human corneal epithelial cells.Viability of corneal epithelial cells was determined using commercially available MTT and CyQUANT?assays.RESULTS:At a concentration of 6 mmol/L,insult with NaOH leads to reduced corneal epithelial cell viability by approximately 30%.This reduced viability was prevented by treating the cells after initial insult with the 20-amino acid renalase derived peptide(RP-220).CONCLUSION:RP-220 has a pro-survival role for RP-220 following alkaline insult to corneal epithelial cells.

Curative effect and possible mechanism of taurine on early corneal alkali burns

To the Editor:Corneal alkali burns(CABs)have been a difficult problem in clinical treatment for a long time.In severe cases,blindness occurs;hence,research on the repair mechanism underlying corneal injury is particularly important to identify potential therapeutic targets.Alkali-induced corneal injuries often trigger aggressive aseptic inflammatory responses,which are key to autoimmune responses.[1]However,Nod-like receptor protein 3(NLRP3)inflammasomes play an important role in aseptic inflammation.[2]Under stimuli,such as infection or stress,the activated NLRP3 inflammasome not only processes procaspase-1 into mature caspase-1 but also further promotes the maturation and release of interleukin(IL)-1βand IL-18.[3]Taurine(Tau)is widely distributed in ocular structures and is an immune regulator.Tau can maintain the stability of the corneal epithelium and improve the survival rate of corneal epithelial cells through antioxidant effects.[4]The purpose of this study was to investigate the effect of Tau eye drops on CAB and elucidate the mechanism underlying corneal inflammatory responses.

The experimental research on the treatment of rabbits with acute cornea alkali burn by taking bone marrow mesenchymal stem cell

Objective:To study the effect of bone marrow mesenchymal stem cell(BMSCs) on angiogenesis and inflammation in rabbits with acute cornea alkali burn.Methods:New Zealand White Rabbit were chosen,while model of cornea alkali bum was made and divided into BMSCs group and control group.Rabbits in the BMSCs group were injected with BMSCs and those in the control group received PBS Solution via ear vein.Cornea turbidity and the angiogenesis area were measured at 20 d,40 d,60 d.The expression of angiogenic and inflammation response cytokines were measured at 60 d.Results:At 20 d,40 d,60 d,the cornea turbidity in BMSCs group was lower than that in control group,and the angiogenesis area in BMSCs group was smaller than that in control group;At 60 d,the mRNA expression of HIF-1 α,VEGF,MMP2,MMP9,TLR2,TLR4,IL-1 α,IL-1 β,TNF-α,ICAM-1 in cornea of BMSCs group was substantially Lower than that of control group,while BMSCs group was substantially higher than control group on mRNA expression of PEDE TIMP1,TIMP2.Conclusions:BMSCs has inhibitory effect on angiogenesis and inflammatory response so that it is conducive to the healing of cornea alkali burn.

Therapeutic effects of topical netrin-4 in a corneal acute inflammatory model

AIM: To evaluate the therapeutic effect of netrin-4 on the early acute phase of inflammation in the alkali-burned eye.METHODS: Eye drops containing netrin-4 or phosphate buffered saline(PBS) were administered to a alkali-burn-induced corneal acute inflammatory model four times daily. The clinical evaluations, including fluorescein staining and inflammatory index, were performed on day 1, 4 and 7 using slit lamp microscopy.Global specimens were collected on day 7 and processed for immunofluorescent staining. The levels of inflammatory mediators in the corneas were determined by real-time polymerase chain reaction(PCR).RESULTS: Exogenous netrin-4 administered on rat ocular surfaces showed more improvements in decreasing fluorescein staining on day 4 and 7, and resolved alkali burn-induced corneal inflammation index on day 7(P 【0.01). The levels of IL-1β, IL-6, intercellular cell adhesion molecule-1(ICAM-1), vascular cell adhesion molecule-1(VCAM-1), monocyte chemotactic protein-1(MCP-1) and macrophage inflammatory protein-1(MIP-1) in corneas were decreased in netrin-4-treated groups(P 【0.05). In addition, netrin-4 significantly reduced the expression of leukocyte common antigen 45(CD45) in the alkali-burn cornea(P 【0.001).CONCLUSION: Topical netrin-4 accelerated wound healing and reduced the inflammation on alkali-burn rat model, suggesting a potential as an anti-inflammatory agent in the clinical to treat the acute inflammation.

Inhibited experimental corneal neovascularization by neutralizing anti-SDF-1α antibody

AIM: To explore the effect of SDF-1α on the development of experimental corneal neovascularization (CRNV).METHODS: CRNV was induced by alkali injury in mice. The expression of SDF-1α and CXCR4 in burned corneas was examined by Flow Cytometry. Neutralizing anti-mouse SDF-1α antibody was locally administrated after alkali injury and the formation of CRNV 2 weeks after injury was assessed by Immunohistochemistry. The expression of VEGF and C-Kit in burned corneas was detected by RT-PCR.RESULTS: The number of CRNV peaks at 2 weeks after alkali injury. Compared to control group, SDF-1α neutralizing antibody treatment significantly decreased the number of CRNV. RT-PCR confirmed that SDF-1α neutralizing antibody treatment resulted in decreased intracorneal VEGF and C-Kit expression.CONCLUSION: SDF-1α neutralizing antibody treated mice exhibited impaired experimental CRNV through down regulated VEGF and C-Kit expression.