The efficacy of electroacupuncture in the treatment of peripheral facial paralysis is known, but the specific mechanism has not been clarified. Glial cell-derived neurotrophic factor(GDNF) has been shown to protect ne...The efficacy of electroacupuncture in the treatment of peripheral facial paralysis is known, but the specific mechanism has not been clarified. Glial cell-derived neurotrophic factor(GDNF) has been shown to protect neurons by binding to N-cadherin. Our previous results have shown that electroacupuncture could increase the expression of N-cadherin mRNA in facial neurons and promote facial nerve regeneration. In this study, the potential mechanisms by which electroacupuncture promotes nerve regeneration were elucidated through assessing the effects of electroacupuncture on GDNF and N-cadherin expression in facial motoneurons of rabbits with peripheral facial nerve crush injury. New Zealand rabbits were randomly divided into a normal group(normal control, n = 21), injury group(n = 45) and electroacupuncture group(n = 45). Model rabbits underwent facial nerve crush injury only. Rabbits in the electroacupuncture group received facial nerve injury, and then underwent electroacupuncture at Yifeng(TE17), Jiache(ST6), Sibai(ST2), Dicang(ST4), Yangbai(GB14), Quanliao(SI18), and Hegu(LI4; only acupuncture, no electrical stimulation). The results showed that in behavioral assessments, the total scores of blink reflex, vibrissae movement, and position of apex nasi, were markedly lower in the EA group than those in the injury group. Hematoxylin-eosin staining of the right buccinator muscle of each group showed that the cross-sectional area of buccinator was larger in the electroacupuncture group than in the injury group on days 1, 14 and 21 post-surgery. Toluidine blue staining of the right facial nerve tissue of each group revealed that on day 14 post-surgery, there was less axonal demyelination and fewer inflammatory cells in the electroacupuncture group compared with the injury group. Quantitative real time-polymerase chain reaction showed that compared with the injury group, N-cadherin mRNA levels on days 4, 7, 14 and 21 and GDNF mRNA levels on days 4, 7 and 14 were significantly higher in the electroacupuncture group. Western blot assay displayed that compared with the injury group, the expression of GDNF protein levels on days 7, 14 and 21 were significantly upregulated in the electroacupuncture group. The histology with hematoxylin-eosin staining and Nissl staining of brainstem tissues containing facial neurons in the middle and lower part of the pons exhibited that on day 7 post-surgery, there were significantly fewer apoptotic neurons in the electroacupuncture group than in the injury group. By day 21, there was no significantly difference in the number of neurons between the electroacupuncture and normal groups. Taken together, these results have confirmed that electroacupuncture promotes regeneration of peripheral facial nerve injury in rabbits, inhibits neuronal apoptosis, and reduces peripheral inflammatory response, resulting in the recovery of facial muscle function. This is achieved by up-regulating the expression of GDNF and N-cadherin in central facial neurons.展开更多
Objective The present study aimed to explore the role of P2Y1 receptor in glial fibrillary acidic protein （GFAP） production and glial cell line-derived neurotrophic factor （GDNF） secretion of astrocytes under isch...Objective The present study aimed to explore the role of P2Y1 receptor in glial fibrillary acidic protein （GFAP） production and glial cell line-derived neurotrophic factor （GDNF） secretion of astrocytes under ischemic insult and the related signaling pathways. Methods Using transient right middle cerebral artery occlusion （tMCAO） and oxygen-glucose-serum deprivation for 2 h as the model of ischemic injury in vivo and in vitro, immunofluorescence, quantitative real-time reverse transcription-polymerase chain reaction （RT-PCR）, Western blotting, enzyme linked immunosorbent assay （ELISA） were used to investigate location of P2Y1 receptor and GDNF, the expression of GFAP and GDNF, and the changes of signaling molecules. Results Blockage of P2Y1 receptor with the selective antagonist N^6-methyl-2′-deoxyadenosine 3′,5′-bisphosphate diammonium （MRS2179） reduced GFAP production and increased GDNF production in the antagonist group as compared with simple ischemic group both in vivo and in vitro. Oxygen-glucose-serum deprivation and blockage of P2Y1 receptor caused elevation of phosphorylated Akt and cAMP response element binding protein （CREB）, and reduction of phosphorylated Janus kinase2 （JAK2） and signal transducer and activator of transcription3 （STAT3, Ser727）. After blockage of P2Y1 receptor and deprivation of oxygen-glucose-serum, AG490 （inhibitor of JAK2） reduced phosphorylation of STAT3 （Ser727） as well as expression of GFAP; LY294002, an inhibitor of phosphatidylinositol 3-kinase （PI3-K）, decreased phosphorylation of Akt and CREB; the inhibitor of mitogen-activated protein kinase kinase 1/2 （MEK 1/2） U0126, an important molecule of Ras/extracellular signal- regulated kinase （ERK） signaling pathway, decreased the phosphorylation of JAK2, STAT3 （Ser727）, Akt and CREB. Conclusion These results suggest that P2Y1 receptor plays a role in the production of GFAP and GDNF in astrocytes under transient ischemic condition and the related signaling pathways may be JAK2/STAT3 and PI3-K/Akt/CREB, respectively, and that crosstalk probably exists between them.展开更多
Objective:To investigate the interference and expression of human glial cell line-derived neurotrophic factor(hCDNF) and soluble TNF alpha(sTMFRⅠ) receptor genes in neural stem cells and to evaluate the roles of thes...Objective:To investigate the interference and expression of human glial cell line-derived neurotrophic factor(hCDNF) and soluble TNF alpha(sTMFRⅠ) receptor genes in neural stem cells and to evaluate the roles of these proteins in the genetic treatment of spinal cord injury.Methods:Full-length of GDNF cDNA(538 bp) and sTMFRⅠcDNA(504 bp) were inserted into the early 1 region of adenovirus genomic DNA respectively and were immediated by the human cytomegalovirus(gene promoter/enhancer). These adenoviruses were propagated in HEK293 cells via homologous recombination for 7-10 days in vivo,then they were used to infect human neural stem ceils.The infection and expression of gene were tested under immunofluorescence.ELISA and Westem-blot after 48 hours.Results:Almost all the cultured cells showed the nestin immunofluorescence positive staining,which was the characteristics of neural stem cell.A great quantity of EGFP and KFP were observed in neural stem cells,which indicated the expression of GDNF and sTMFRⅠ.After transfection of GDNF and sTMFRⅠgenes,many neural stem cells show GFAP and tubulin immunofluorescence positive staining,which meant that most neural stem cells differentiated into neuron at that condition.Conclusions:The infective efficiency of adenovirus is greatly acceptable to neural stem cell,thus adenovirus provide a useful vector for exogenous GDNF and sTMFRⅠgenes expressing in neural stem cells,which is useful for differentiation of neural stem cell.展开更多
Aging is a physiological event dependent on multiple pathways that are linked to lifespan and processes leading to cognitive decline.This process represents the major risk factor for aging-related diseases such as Alz...Aging is a physiological event dependent on multiple pathways that are linked to lifespan and processes leading to cognitive decline.This process represents the major risk factor for aging-related diseases such as Alzheimer’s disease,Parkinson’s disease,and ischemic stroke.The incidence of all these pathologies increases exponentially with age.Research on aging biology has currently focused on elucidating molecular mechanisms leading to the development of those pathologies.Cognitive deficit and neurodegeneration,common features of aging-related pathologies,are related to the alteration of the activity and levels of neurotrophic factors,such as brain-derived neurotrophic factor,nerve growth factor,and glial cell-derived neurotrophic factor.For this reason,treatments that modulate neurotrophin levels have acquired a great deal of interest in preventing neurodegeneration and promoting neural regeneration in several neurological diseases.Those treatments include both the direct administration of neurotrophic factors and the induced expression with viral vectors,neurotrophins’binding with biomaterials or other molecules to increase their bioavailability but also cell-based therapies.Considering neurotrophins’crucial role in aging pathologies,here we discuss the involvement of several neurotrophic factors in the most common brain aging-related diseases and the most recent therapeutic approaches that provide direct and sustained neurotrophic support.展开更多
Glial cell line-derived neurotrophic factor(GDNF) plays a critical role in neuronal survival and function. GDNF has two major splice variants in the brain,α-pro-GDNF and β-pro-GDNF, and both isoforms have strong neu...Glial cell line-derived neurotrophic factor(GDNF) plays a critical role in neuronal survival and function. GDNF has two major splice variants in the brain,α-pro-GDNF and β-pro-GDNF, and both isoforms have strong neuroprotective effects on dopamine neurons. However, the expression of the GDNF splice variants in dopaminergic neurons in the brain remains unclear. Therefore, in this study, we investigated the mRNA and protein expression of α-and β-pro-GDNF in the mouse brain by real-time quantitative polymerase chain reaction, using splice variant-specific primers, and western blot analysis. At the mRNA level,β-pro-GDNF expression was significantly greater than that of α-pro-GDNF in the mouse brain. In contrast, at the protein level,α-pro-GDNF expression was markedly greater than that of β-pro-GDNF. To clarify the mechanism underlying this inverse relationship in mRNA and protein expression levels of the GDNF splice variants, we analyzed the expression of sorting protein-related receptor with A-type repeats(SorLA) by real-time quantitative polymerase chain reaction. At the mRNA level, SorLA was positively associated with β-pro-GDNF expression, but not with α-pro-GDNF expression. This suggests that the differential expression of α-and β-pro-GDNF in the mouse brain is related to SorLA expression. As a sorting protein, SorLA could contribute to the inverse relationship among the mRNA and protein levels of the GDNF isoforms. This study was approved by the Animal Ethics Committee of Xuzhou Medical University, China on July 14, 2016.展开更多
Background: Spinal cord injury (SCI) is a worldwide medical concern. This study aimed to elucidate the mechanism underlying protective effect of hyperbaric oxygen (HBO) against SCI-induced neurologic defects in rats v...Background: Spinal cord injury (SCI) is a worldwide medical concern. This study aimed to elucidate the mechanism underlying protective effect of hyperbaric oxygen (HBO) against SCI-induced neurologic defects in rats via exploring the stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) axis and expression of brain-derived neurotrophic factor (BDNF). Methods: An acute SCI rat model was established in Sprague-Dawley rats using the Allen method. Sixty rats were divided into four groups (w = 15 in each group): sham-operated, SCI, SCI treated with HBO (SCI + HBO), and SCI treated with both HBO and AMD3100 (an antagonist of CXCR4;SCI + HBO + AMD) groups. The rats were treated with HBO twice a day for 3 days and thereafter once a day after the surgery for up to 28 days. Following the surgery, neurologic assessments were performed with the Basso-Bettie-Bresnahan (BBB) scoring system on postoperative day (POD) 7, 14, 21, and 28. Spinal cord tissues were harvested to assess the expression of SDF-1, CXCR4, and BDNF at mRNA and protein levels, using quantitative real-time polymerase chain reaction, Western blot analysis, and histopathologic analysis. Results: HBO treatment recovered SCI-induced descent of BBB scores on POD 14,(1.25±0.75 vs. 1.03 ±0.66, P< 0.05), 21 (5.27± 0.89 vs. 2.56± 1.24, P< 0.05), and 28 (11.35±0.56 vs. 4.23± 1.20, P<0.05) compared with the SCI group. Significant differences were found in the mRNA levels of SDF-1 (mRNA: day 21, SCI + HBO vs. SCI + HBO + AMD, 2.89± 1.60 vs. 1.56±0.98, P<0.05), CXCR4 (mRNA: day 7, SCI + HBO vs. SCI, 2.99± 1.60 vs. 1.31 ±0.98, P<0.05;day 14, SCI + HBO vs. SCI + HBO + AMD, 4.18± 1.60 vs. 0.80±0.34, P<0.05;day 21, SCI + HBO vs. SCI, 2.10±1.01 vs.1.15±0.03, P<0.05), and BDNF (mRNA: day 7, SCI + HBO vs. SCI, 3.04±0.41 vs. 2.75±0.31, P<0.05;day 14, SCI + HBO vs. SCI, 3.88± 1.59 vs. 1.11 ±0.40, P<0.05), indicating the involvement of SDF-1/CXCR4 axis in the protective effect of HBO. Conclusions: HBO might promote the recovery of neurologic function after SCI in rats via activating the SDF-1/CXCR4 axis and promoting BDNF expression.展开更多
The gold standard for treating peripheral nerve injuries that have large nerve gaps where the nerves cannot be directly sutured back together because it creates tension on the nerve,is to incorporate an autologous ner...The gold standard for treating peripheral nerve injuries that have large nerve gaps where the nerves cannot be directly sutured back together because it creates tension on the nerve,is to incorporate an autologous nerve graft.However,even with the incorporation of a nerve graft,generally patients only regain a small portion of function in limbs affected by the injury.Although,there has been some promising results using growth factors to induce more axon growth through the nerve graft,many of these previous therapies are limited in their ability to release growth factors in a sustained manner and tailor them to a desired time frame.The ideal drug delivery platform would deliver growth factors at therapeutic levels for enough time to grow axons the entire length of the nerve graft.We hypothesized that mineral coated microparticles(MCMs)would bind,stabilize and release biologically active glial cell-derived neurotrophic factor(GDNF)and nerve growth factor(NGF)in a sustained manner.Therefore,the objective of this study was to test the ability of MCMs releasing growth factors at the distal end of a 10 mm sciatic nerve graft,to induce axon growth through the nerve graft and restore hind limb function.After sciatic nerve grafting in Lewis rats,the hind limb function was tested weekly by measuring the angle of the ankle at toe lift-off while walking down a track.Twelve weeks after grafting,the grafts were harvested and myelinated axons were analyzed proximal to the graft,in the center of the graft,and distal to the graft.Under physiological conditions in vitro,the MCMs delivered a burst release of NGF and GDNF for 3 days followed by a sustained release for at least 22 days.In vivo,MCMs releasing NGF and GDNF at the distal end of sciatic nerve grafts resulted in significantly more myelinated axons extending distal to the graft when compared to rats that received nerve grafts without growth factor treatment.The rats with nerve grafts incorporated with MCMs releasing NGF and GDNF also showed significant improvement in hind limb function starting at 7 weeks postoperatively and continuing through 12 weeks postoperatively when compared to rats that received nerve grafts without growth factor treatment.In conclusion,MCMs released biologically active NGF and GDNF in a sustained manner,which significantly enhanced axon growth resulting in a significant improvement of hind limb function in rats.The animal experiments were approved by University of Wisconsin-Madison Animal Care and Use Committee(ACUC,protocol#M5958)on January 3,2018.展开更多
文摘The efficacy of electroacupuncture in the treatment of peripheral facial paralysis is known, but the specific mechanism has not been clarified. Glial cell-derived neurotrophic factor(GDNF) has been shown to protect neurons by binding to N-cadherin. Our previous results have shown that electroacupuncture could increase the expression of N-cadherin mRNA in facial neurons and promote facial nerve regeneration. In this study, the potential mechanisms by which electroacupuncture promotes nerve regeneration were elucidated through assessing the effects of electroacupuncture on GDNF and N-cadherin expression in facial motoneurons of rabbits with peripheral facial nerve crush injury. New Zealand rabbits were randomly divided into a normal group(normal control, n = 21), injury group(n = 45) and electroacupuncture group(n = 45). Model rabbits underwent facial nerve crush injury only. Rabbits in the electroacupuncture group received facial nerve injury, and then underwent electroacupuncture at Yifeng(TE17), Jiache(ST6), Sibai(ST2), Dicang(ST4), Yangbai(GB14), Quanliao(SI18), and Hegu(LI4; only acupuncture, no electrical stimulation). The results showed that in behavioral assessments, the total scores of blink reflex, vibrissae movement, and position of apex nasi, were markedly lower in the EA group than those in the injury group. Hematoxylin-eosin staining of the right buccinator muscle of each group showed that the cross-sectional area of buccinator was larger in the electroacupuncture group than in the injury group on days 1, 14 and 21 post-surgery. Toluidine blue staining of the right facial nerve tissue of each group revealed that on day 14 post-surgery, there was less axonal demyelination and fewer inflammatory cells in the electroacupuncture group compared with the injury group. Quantitative real time-polymerase chain reaction showed that compared with the injury group, N-cadherin mRNA levels on days 4, 7, 14 and 21 and GDNF mRNA levels on days 4, 7 and 14 were significantly higher in the electroacupuncture group. Western blot assay displayed that compared with the injury group, the expression of GDNF protein levels on days 7, 14 and 21 were significantly upregulated in the electroacupuncture group. The histology with hematoxylin-eosin staining and Nissl staining of brainstem tissues containing facial neurons in the middle and lower part of the pons exhibited that on day 7 post-surgery, there were significantly fewer apoptotic neurons in the electroacupuncture group than in the injury group. By day 21, there was no significantly difference in the number of neurons between the electroacupuncture and normal groups. Taken together, these results have confirmed that electroacupuncture promotes regeneration of peripheral facial nerve injury in rabbits, inhibits neuronal apoptosis, and reduces peripheral inflammatory response, resulting in the recovery of facial muscle function. This is achieved by up-regulating the expression of GDNF and N-cadherin in central facial neurons.
基金the National Natural Science Foundation of China (No. 30500189)
文摘Objective The present study aimed to explore the role of P2Y1 receptor in glial fibrillary acidic protein （GFAP） production and glial cell line-derived neurotrophic factor （GDNF） secretion of astrocytes under ischemic insult and the related signaling pathways. Methods Using transient right middle cerebral artery occlusion （tMCAO） and oxygen-glucose-serum deprivation for 2 h as the model of ischemic injury in vivo and in vitro, immunofluorescence, quantitative real-time reverse transcription-polymerase chain reaction （RT-PCR）, Western blotting, enzyme linked immunosorbent assay （ELISA） were used to investigate location of P2Y1 receptor and GDNF, the expression of GFAP and GDNF, and the changes of signaling molecules. Results Blockage of P2Y1 receptor with the selective antagonist N^6-methyl-2′-deoxyadenosine 3′,5′-bisphosphate diammonium （MRS2179） reduced GFAP production and increased GDNF production in the antagonist group as compared with simple ischemic group both in vivo and in vitro. Oxygen-glucose-serum deprivation and blockage of P2Y1 receptor caused elevation of phosphorylated Akt and cAMP response element binding protein （CREB）, and reduction of phosphorylated Janus kinase2 （JAK2） and signal transducer and activator of transcription3 （STAT3, Ser727）. After blockage of P2Y1 receptor and deprivation of oxygen-glucose-serum, AG490 （inhibitor of JAK2） reduced phosphorylation of STAT3 （Ser727） as well as expression of GFAP; LY294002, an inhibitor of phosphatidylinositol 3-kinase （PI3-K）, decreased phosphorylation of Akt and CREB; the inhibitor of mitogen-activated protein kinase kinase 1/2 （MEK 1/2） U0126, an important molecule of Ras/extracellular signal- regulated kinase （ERK） signaling pathway, decreased the phosphorylation of JAK2, STAT3 （Ser727）, Akt and CREB. Conclusion These results suggest that P2Y1 receptor plays a role in the production of GFAP and GDNF in astrocytes under transient ischemic condition and the related signaling pathways may be JAK2/STAT3 and PI3-K/Akt/CREB, respectively, and that crosstalk probably exists between them.
基金Shenzhen Science and Technology Project(No.201103061)
文摘Objective:To investigate the interference and expression of human glial cell line-derived neurotrophic factor(hCDNF) and soluble TNF alpha(sTMFRⅠ) receptor genes in neural stem cells and to evaluate the roles of these proteins in the genetic treatment of spinal cord injury.Methods:Full-length of GDNF cDNA(538 bp) and sTMFRⅠcDNA(504 bp) were inserted into the early 1 region of adenovirus genomic DNA respectively and were immediated by the human cytomegalovirus(gene promoter/enhancer). These adenoviruses were propagated in HEK293 cells via homologous recombination for 7-10 days in vivo,then they were used to infect human neural stem ceils.The infection and expression of gene were tested under immunofluorescence.ELISA and Westem-blot after 48 hours.Results:Almost all the cultured cells showed the nestin immunofluorescence positive staining,which was the characteristics of neural stem cell.A great quantity of EGFP and KFP were observed in neural stem cells,which indicated the expression of GDNF and sTMFRⅠ.After transfection of GDNF and sTMFRⅠgenes,many neural stem cells show GFAP and tubulin immunofluorescence positive staining,which meant that most neural stem cells differentiated into neuron at that condition.Conclusions:The infective efficiency of adenovirus is greatly acceptable to neural stem cell,thus adenovirus provide a useful vector for exogenous GDNF and sTMFRⅠgenes expressing in neural stem cells,which is useful for differentiation of neural stem cell.
文摘Aging is a physiological event dependent on multiple pathways that are linked to lifespan and processes leading to cognitive decline.This process represents the major risk factor for aging-related diseases such as Alzheimer’s disease,Parkinson’s disease,and ischemic stroke.The incidence of all these pathologies increases exponentially with age.Research on aging biology has currently focused on elucidating molecular mechanisms leading to the development of those pathologies.Cognitive deficit and neurodegeneration,common features of aging-related pathologies,are related to the alteration of the activity and levels of neurotrophic factors,such as brain-derived neurotrophic factor,nerve growth factor,and glial cell-derived neurotrophic factor.For this reason,treatments that modulate neurotrophin levels have acquired a great deal of interest in preventing neurodegeneration and promoting neural regeneration in several neurological diseases.Those treatments include both the direct administration of neurotrophic factors and the induced expression with viral vectors,neurotrophins’binding with biomaterials or other molecules to increase their bioavailability but also cell-based therapies.Considering neurotrophins’crucial role in aging pathologies,here we discuss the involvement of several neurotrophic factors in the most common brain aging-related diseases and the most recent therapeutic approaches that provide direct and sustained neurotrophic support.
基金supported by the National Natural Science Foundation of China,No.81772688(to DSG)the Postdoctoral Science Foundation of Jiangsu Province of China,No.1202119C(to HL)
文摘Glial cell line-derived neurotrophic factor(GDNF) plays a critical role in neuronal survival and function. GDNF has two major splice variants in the brain,α-pro-GDNF and β-pro-GDNF, and both isoforms have strong neuroprotective effects on dopamine neurons. However, the expression of the GDNF splice variants in dopaminergic neurons in the brain remains unclear. Therefore, in this study, we investigated the mRNA and protein expression of α-and β-pro-GDNF in the mouse brain by real-time quantitative polymerase chain reaction, using splice variant-specific primers, and western blot analysis. At the mRNA level,β-pro-GDNF expression was significantly greater than that of α-pro-GDNF in the mouse brain. In contrast, at the protein level,α-pro-GDNF expression was markedly greater than that of β-pro-GDNF. To clarify the mechanism underlying this inverse relationship in mRNA and protein expression levels of the GDNF splice variants, we analyzed the expression of sorting protein-related receptor with A-type repeats(SorLA) by real-time quantitative polymerase chain reaction. At the mRNA level, SorLA was positively associated with β-pro-GDNF expression, but not with α-pro-GDNF expression. This suggests that the differential expression of α-and β-pro-GDNF in the mouse brain is related to SorLA expression. As a sorting protein, SorLA could contribute to the inverse relationship among the mRNA and protein levels of the GDNF isoforms. This study was approved by the Animal Ethics Committee of Xuzhou Medical University, China on July 14, 2016.
文摘Background: Spinal cord injury (SCI) is a worldwide medical concern. This study aimed to elucidate the mechanism underlying protective effect of hyperbaric oxygen (HBO) against SCI-induced neurologic defects in rats via exploring the stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) axis and expression of brain-derived neurotrophic factor (BDNF). Methods: An acute SCI rat model was established in Sprague-Dawley rats using the Allen method. Sixty rats were divided into four groups (w = 15 in each group): sham-operated, SCI, SCI treated with HBO (SCI + HBO), and SCI treated with both HBO and AMD3100 (an antagonist of CXCR4;SCI + HBO + AMD) groups. The rats were treated with HBO twice a day for 3 days and thereafter once a day after the surgery for up to 28 days. Following the surgery, neurologic assessments were performed with the Basso-Bettie-Bresnahan (BBB) scoring system on postoperative day (POD) 7, 14, 21, and 28. Spinal cord tissues were harvested to assess the expression of SDF-1, CXCR4, and BDNF at mRNA and protein levels, using quantitative real-time polymerase chain reaction, Western blot analysis, and histopathologic analysis. Results: HBO treatment recovered SCI-induced descent of BBB scores on POD 14,(1.25±0.75 vs. 1.03 ±0.66, P< 0.05), 21 (5.27± 0.89 vs. 2.56± 1.24, P< 0.05), and 28 (11.35±0.56 vs. 4.23± 1.20, P<0.05) compared with the SCI group. Significant differences were found in the mRNA levels of SDF-1 (mRNA: day 21, SCI + HBO vs. SCI + HBO + AMD, 2.89± 1.60 vs. 1.56±0.98, P<0.05), CXCR4 (mRNA: day 7, SCI + HBO vs. SCI, 2.99± 1.60 vs. 1.31 ±0.98, P<0.05;day 14, SCI + HBO vs. SCI + HBO + AMD, 4.18± 1.60 vs. 0.80±0.34, P<0.05;day 21, SCI + HBO vs. SCI, 2.10±1.01 vs.1.15±0.03, P<0.05), and BDNF (mRNA: day 7, SCI + HBO vs. SCI, 3.04±0.41 vs. 2.75±0.31, P<0.05;day 14, SCI + HBO vs. SCI, 3.88± 1.59 vs. 1.11 ±0.40, P<0.05), indicating the involvement of SDF-1/CXCR4 axis in the protective effect of HBO. Conclusions: HBO might promote the recovery of neurologic function after SCI in rats via activating the SDF-1/CXCR4 axis and promoting BDNF expression.
文摘The gold standard for treating peripheral nerve injuries that have large nerve gaps where the nerves cannot be directly sutured back together because it creates tension on the nerve,is to incorporate an autologous nerve graft.However,even with the incorporation of a nerve graft,generally patients only regain a small portion of function in limbs affected by the injury.Although,there has been some promising results using growth factors to induce more axon growth through the nerve graft,many of these previous therapies are limited in their ability to release growth factors in a sustained manner and tailor them to a desired time frame.The ideal drug delivery platform would deliver growth factors at therapeutic levels for enough time to grow axons the entire length of the nerve graft.We hypothesized that mineral coated microparticles(MCMs)would bind,stabilize and release biologically active glial cell-derived neurotrophic factor(GDNF)and nerve growth factor(NGF)in a sustained manner.Therefore,the objective of this study was to test the ability of MCMs releasing growth factors at the distal end of a 10 mm sciatic nerve graft,to induce axon growth through the nerve graft and restore hind limb function.After sciatic nerve grafting in Lewis rats,the hind limb function was tested weekly by measuring the angle of the ankle at toe lift-off while walking down a track.Twelve weeks after grafting,the grafts were harvested and myelinated axons were analyzed proximal to the graft,in the center of the graft,and distal to the graft.Under physiological conditions in vitro,the MCMs delivered a burst release of NGF and GDNF for 3 days followed by a sustained release for at least 22 days.In vivo,MCMs releasing NGF and GDNF at the distal end of sciatic nerve grafts resulted in significantly more myelinated axons extending distal to the graft when compared to rats that received nerve grafts without growth factor treatment.The rats with nerve grafts incorporated with MCMs releasing NGF and GDNF also showed significant improvement in hind limb function starting at 7 weeks postoperatively and continuing through 12 weeks postoperatively when compared to rats that received nerve grafts without growth factor treatment.In conclusion,MCMs released biologically active NGF and GDNF in a sustained manner,which significantly enhanced axon growth resulting in a significant improvement of hind limb function in rats.The animal experiments were approved by University of Wisconsin-Madison Animal Care and Use Committee(ACUC,protocol#M5958)on January 3,2018.
