The transplantation of polylactic glycolic acid conduits combining bone marrow mesenchymal stem cells and extracellular matrix gel for the repair of sciatic nerve injury is effective in some respects, but few data com...The transplantation of polylactic glycolic acid conduits combining bone marrow mesenchymal stem cells and extracellular matrix gel for the repair of sciatic nerve injury is effective in some respects, but few data comparing the biomechanical factors related to the sciatic nerve are available. In the present study, rabbit models of 10-mm sciatic nerve defects were prepared. The rabbit models were repaired with autologous nerve, a polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells, or a polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells ＋ extracellular matrix gel. After 24 weeks, mechanical testing was performed to determine the stress relaxation and creep parameters. Following sciatic nerve injury, the magnitudes of the stress decrease and strain increase at 7,200 seconds were largest in the polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells ＋ extracellular matrix gel group, followed by the polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells group, and then the autologous nerve group. Hematoxylin-eosin staining demonstrated that compared with the polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells group and the autologous nerve group, a more complete sciatic nerve regeneration was found, including good myelination, regularly arranged nerve fibers, and a completely degraded and resorbed conduit, in the polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells ＋ extracellular matrix gel group. These results indicate that bridging 10-mm conduit ＋ bone marrow mesenchymal stem sciatic nerve defects with a polylactic glycolic acid cells ＋ extracellular matrix gel construct increases the stress relaxation under a constant strain, reducing anastomotic tension. Large elongations under a constant physiological load can limit the anastomotic opening and shift, which is beneficial for the regeneration and functional reconstruction of sciatic nerve. Better regeneration was found with the polylactic gly展开更多
Nerve grafting has always been necessary when the contralateral C7 nerve root is transferred to treat brachial plexus injury. Acellular nerve allograft is a promising alternative for the treatment of nerve defects, an...Nerve grafting has always been necessary when the contralateral C7 nerve root is transferred to treat brachial plexus injury. Acellular nerve allograft is a promising alternative for the treatment of nerve defects, and results were improved by grafts laden with differentiated adipose stem cells. However, use of these tissue-engineered nerve grafts has not been reported for the treatment of brachial plexus injury. The aim of the present study was to evaluate the outcome of acellular nerve allografts seeded with differentiated adipose stem cells to improve nerve regeneration in a rat model in which the contralateral C7 nerve was transferred to repair an upper brachial plexus injury. Differentiated adipose stem cells were obtained from Sprague-Dawley rats and transdifferentiated into a Schwann cell-like phenotype. Acellular nerve allografts were prepared from 15-mm bilateral sections of rat sciatic nerves. Rats were randomly divided into three groups: acellular nerve allograft, acellular nerve allograft + differentiated adipose stem cells, and autograft. The upper brachial plexus injury model was established by traction applied away from the intervertebral foramen with micro-hemostat forceps. Acellular nerve allografts with or without seeded cells were used to bridge the gap between the contralateral C7 nerve root and C5–6 nerve. Histological staining, electrophysiology, and neurological function tests were used to evaluate the effect of nerve repair 16 weeks after surgery. Results showed that the onset of discernible functional recovery occurred earlier in the autograft group first, followed by the acellular nerve allograft + differentiated adipose stem cells group, and then the acellular nerve allograft group;moreover, there was a significant difference between autograft and acellular nerve allograft groups. Compared with the acellular nerve allograft group, compound muscle action potential, motor conduction velocity, positivity for neurofilament and S100, diameter of regenerating axons, myelin sheath thickness,展开更多
Studies have shown that retreatment of the distal stoma after nerve grafting can stimulate nerve regeneration. The present study attempted to verify the effects of reanastomosis of the distal stoma, after nerve grafti...Studies have shown that retreatment of the distal stoma after nerve grafting can stimulate nerve regeneration. The present study attempted to verify the effects of reanastomosis of the distal stoma, after nerve grafting, on nerve regeneration by assessing brain-derived neurotrophic factor expression in 2-month-old rats. Results showed that brain-derived neurotrophic factor expression in L2-4 dorsal root ganglia began to increase 3 days after autologous nerve grafting post sciatic nerve injury, peaked at 14 days, decreased at 28 days, and reached similar levels to the sham-surgery group at 56 days. Brain-derived neurotrophic factor expression in L2-4 dorsal root ganglia began to increase 3 days after reanastomosis of the distal stoma, 59 days after autologous nerve grafting post sciatic nerve injury, significantly increased at 63 days, peaked at 70 days, and gradually decreased thereafter, but remained higher compared with the sham-surgery group up to 112 days. The results of this study indicate that reanastomosis of the distal stoma after orthotopic nerve grafting stimulated brain-derived neurotrophic factor expression in L2.4 dorsal root ganglia.展开更多
Peripheral nerve injury is a serious disease and its repair is challenging. A cable-style autologous graft is the gold standard for repairing long peripheral nerve defects; however, ensuring that the minimum number of...Peripheral nerve injury is a serious disease and its repair is challenging. A cable-style autologous graft is the gold standard for repairing long peripheral nerve defects; however, ensuring that the minimum number of transplanted nerve attains maximum therapeutic effect remains poorly understood. In this study, a rat model of common peroneal nerve defect was established by resecting a 10-mm long right common peroneal nerve. Rats receiving transplantation of the common peroneal nerve in situ were designated as the in situ graft group. Ipsilateral sural nerves（10–30 mm long） were resected to establish the one sural nerve graft group, two sural nerves cable-style nerve graft group and three sural nerves cable-style nerve graft group. Each bundle of the peroneal nerve was 10 mm long. To reduce the barrier effect due to invasion by surrounding tissue and connective-tissue overgrowth between neural stumps, small gap sleeve suture was used in both proximal and distal terminals to allow repair of the injured common peroneal nerve. At three months postoperatively, recovery of nerve function and morphology was observed using osmium tetroxide staining and functional detection. The results showed that the number of regenerated nerve fibers, common peroneal nerve function index, motor nerve conduction velocity, recovery of myodynamia, and wet weight ratios of tibialis anterior muscle were not significantly different among the one sural nerve graft group, two sural nerves cable-style nerve graft group, and three sural nerves cable-style nerve graft group. These data suggest that the repair effect achieved using one sural nerve graft with a lower number of nerve fibers is the same as that achieved using the two sural nerves cable-style nerve graft and three sural nerves cable-style nerve graft. This indicates that according to the ‘multiple amplification＇ phenomenon, one small nerve graft can provide a good therapeutic effect for a large peripheral nerve defect.展开更多
Previous studies have shown that exogenous gangliosides promote nervous system regeneration and synapse formation. In this study, 10 mm sciatic nerve segments from New Zealand rabbits were thawed from cryopreservation...Previous studies have shown that exogenous gangliosides promote nervous system regeneration and synapse formation. In this study, 10 mm sciatic nerve segments from New Zealand rabbits were thawed from cryopreservation and were used for the repair of left sciatic nerve defects through allograft bridging. Three days later, 1 mL ganglioside solution （1 g/L） was sub- cutaneously iniected into the right hind leg of rabbits. Compared with non-injected rats, muscle wet weight ratio was increased at 2-12 weeks after modeling. The quantity of myelinated fibers in regenerated sciatic nerve, myelin thickness and fiber diameter were elevated at 4-12 weeks after modeling. Sciatic nerve potential amplitude and conduction velocity were raised at 8 and 12 weeks, while conduction latencies were decreased at 12 weeks. Experimental findings indicate that ganglioside can promote the regeneration of sciatic nerve defects after repair with cryopre- served peripheral nerve allografts.展开更多
In this study, we developed a novel artificial nerve graft termed self-assembling peptide nanofiber scaffold （SAPNS）-containing poly（lactic-co-glycolic acid） （PLGA） conduit （SPC） and used it to bridge a 10-mm-...In this study, we developed a novel artificial nerve graft termed self-assembling peptide nanofiber scaffold （SAPNS）-containing poly（lactic-co-glycolic acid） （PLGA） conduit （SPC） and used it to bridge a 10-mm-long sciatic nerve defect in the rat. Retrograde tracing, behavioral testing and histomorphometric analyses showed that compared with the empty PLGA conduit implantation group, the SPC implantation group had a larger number of growing and extending axons, a markedly increased diameter of regenerated axons and a greater thickness of the myelin sheath in the conduit. Furthermore, there was an increase in the size of the neuromuscular junction and myofiber diameter in the target muscle. These findings suggest that the novel artificial SPC nerve graft can promote axonal regeneration and remyelination in the transected peripheral nerve and can be used for repairing peripheral nerve injury.展开更多
Nerve fibers are attracted by sutureless end-to-side nerve coaptation into the recipient nerve. Opening a window in the epineurium enhances axon attraction and myeliuation. The authors analyze the features of nerve re...Nerve fibers are attracted by sutureless end-to-side nerve coaptation into the recipient nerve. Opening a window in the epineurium enhances axon attraction and myeliuation. The authors analyze the features of nerve repair by end-to-side coaptation. They highlight the known mechanisms of axon sprouting and different hypotheses of start up signals （presence or absence of an epineurial window, role of Schwann cells, signaling from the distal trunk）. The clinical literature is also presented and differences between experimental and clinical applications are pointed out. The authors propose their point of view and perspectives deriving from recent experimental and clinical experiences.展开更多
We previously demonstrated that overexpression of tropomyosin receptor kinase A(TrkA)promotes the survival and Schwann celllike differentiation of bone marrow stromal stem cells in nerve grafts,thereby enhancing the r...We previously demonstrated that overexpression of tropomyosin receptor kinase A(TrkA)promotes the survival and Schwann celllike differentiation of bone marrow stromal stem cells in nerve grafts,thereby enhancing the regeneration and functional recovery of the peripheral nerve.In the present study,we investigated the molecular mechanisms underlying the neuroprotective effects of TrkA in bone marrow stromal stem cells seeded into nerve grafts.Bone marrow stromal stem cells from Sprague-Dawley rats were infected with recombinant lentivirus vector expressing rat TrkA,TrkA-shRNA or the respective control.The cells were then seeded into allogeneic rat acellular nerve allografts for bridging a 1-cm right sciatic nerve defect.Then,8 weeks after surgery,hematoxylin and eosin staining showed that compared with the control groups,the cells and fibers in the TrkA overexpressing group were more densely and uniformly arranged,whereas they were relatively sparse and arranged in a disordered manner in the TrkA-shRNA group.Western blot assay showed that compared with the control groups,the TrkA overexpressing group had higher expression of the myelin marker,myelin basic protein and the axonal marker neurofilament 200.The TrkA overexpressing group also had higher levels of various signaling molecules,including TrkA,pTrkA(Tyr490),extracellular signal-regulated kinases 1/2(Erkl/2),pErk1/2(Thr202/Tyr204),and the anti-apoptotic proteins Bcl-2 and Bcl-xL.In contrast,these proteins were downregulated,while the pro-apoptotic factors Bax and Bad were upregulated,in the TrkA-shRNA group.The levels of the TrkA effectors Akt and pAkt(Ser473)were not different among the groups.These results suggest that TrkA enhances the survival and regenerative capacity of bone marrow stromal stem cells through upregulation of the Erk/Bcl-2 pathway.All procedures were approved by the Animal Ethical and Welfare Committee of Shenzhen University,China in December 2014(approval No.AEWC-2014-001219).展开更多
The hypothesis is that induced pluripotent stem cells (iPSC) derived Schwann cells and/or macrophages can be transplanted into acellular nerve graft in repairing injured nervous system. The efficiency of iPSC seeded a...The hypothesis is that induced pluripotent stem cells (iPSC) derived Schwann cells and/or macrophages can be transplanted into acellular nerve graft in repairing injured nervous system. The efficiency of iPSC seeded acellular nerve graft may mimic the autologous peripheral nerve graft.展开更多
基金supported by the Science and Technology Development Program of Jilin Province in China,No.20110492
文摘The transplantation of polylactic glycolic acid conduits combining bone marrow mesenchymal stem cells and extracellular matrix gel for the repair of sciatic nerve injury is effective in some respects, but few data comparing the biomechanical factors related to the sciatic nerve are available. In the present study, rabbit models of 10-mm sciatic nerve defects were prepared. The rabbit models were repaired with autologous nerve, a polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells, or a polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells ＋ extracellular matrix gel. After 24 weeks, mechanical testing was performed to determine the stress relaxation and creep parameters. Following sciatic nerve injury, the magnitudes of the stress decrease and strain increase at 7,200 seconds were largest in the polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells ＋ extracellular matrix gel group, followed by the polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells group, and then the autologous nerve group. Hematoxylin-eosin staining demonstrated that compared with the polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells group and the autologous nerve group, a more complete sciatic nerve regeneration was found, including good myelination, regularly arranged nerve fibers, and a completely degraded and resorbed conduit, in the polylactic glycolic acid conduit ＋ bone marrow mesenchymal stem cells ＋ extracellular matrix gel group. These results indicate that bridging 10-mm conduit ＋ bone marrow mesenchymal stem sciatic nerve defects with a polylactic glycolic acid cells ＋ extracellular matrix gel construct increases the stress relaxation under a constant strain, reducing anastomotic tension. Large elongations under a constant physiological load can limit the anastomotic opening and shift, which is beneficial for the regeneration and functional reconstruction of sciatic nerve. Better regeneration was found with the polylactic gly
基金supported by the National Natural Science Foundation of China,No.81601057(to JTY)
文摘Nerve grafting has always been necessary when the contralateral C7 nerve root is transferred to treat brachial plexus injury. Acellular nerve allograft is a promising alternative for the treatment of nerve defects, and results were improved by grafts laden with differentiated adipose stem cells. However, use of these tissue-engineered nerve grafts has not been reported for the treatment of brachial plexus injury. The aim of the present study was to evaluate the outcome of acellular nerve allografts seeded with differentiated adipose stem cells to improve nerve regeneration in a rat model in which the contralateral C7 nerve was transferred to repair an upper brachial plexus injury. Differentiated adipose stem cells were obtained from Sprague-Dawley rats and transdifferentiated into a Schwann cell-like phenotype. Acellular nerve allografts were prepared from 15-mm bilateral sections of rat sciatic nerves. Rats were randomly divided into three groups: acellular nerve allograft, acellular nerve allograft + differentiated adipose stem cells, and autograft. The upper brachial plexus injury model was established by traction applied away from the intervertebral foramen with micro-hemostat forceps. Acellular nerve allografts with or without seeded cells were used to bridge the gap between the contralateral C7 nerve root and C5–6 nerve. Histological staining, electrophysiology, and neurological function tests were used to evaluate the effect of nerve repair 16 weeks after surgery. Results showed that the onset of discernible functional recovery occurred earlier in the autograft group first, followed by the acellular nerve allograft + differentiated adipose stem cells group, and then the acellular nerve allograft group;moreover, there was a significant difference between autograft and acellular nerve allograft groups. Compared with the acellular nerve allograft group, compound muscle action potential, motor conduction velocity, positivity for neurofilament and S100, diameter of regenerating axons, myelin sheath thickness,
基金supported by the Key Project of Clinical Subject of the Health Ministry,China (2010-2012),No.[2010]439
文摘Studies have shown that retreatment of the distal stoma after nerve grafting can stimulate nerve regeneration. The present study attempted to verify the effects of reanastomosis of the distal stoma, after nerve grafting, on nerve regeneration by assessing brain-derived neurotrophic factor expression in 2-month-old rats. Results showed that brain-derived neurotrophic factor expression in L2-4 dorsal root ganglia began to increase 3 days after autologous nerve grafting post sciatic nerve injury, peaked at 14 days, decreased at 28 days, and reached similar levels to the sham-surgery group at 56 days. Brain-derived neurotrophic factor expression in L2-4 dorsal root ganglia began to increase 3 days after reanastomosis of the distal stoma, 59 days after autologous nerve grafting post sciatic nerve injury, significantly increased at 63 days, peaked at 70 days, and gradually decreased thereafter, but remained higher compared with the sham-surgery group up to 112 days. The results of this study indicate that reanastomosis of the distal stoma after orthotopic nerve grafting stimulated brain-derived neurotrophic factor expression in L2.4 dorsal root ganglia.
基金supported by the National Basic Research Program of China(973 Program),No.2014CB542200a grant from the Ministry of Education Innovation Team,No.IRT1201+2 种基金the National Natural Science Foundation of China,No.31271284,31171150,81171146,30971526,31100860,31040043,31640045,31671246a grant from the Educational Ministry New Century Excellent Talents Support Project in China,No.BMU20110270a grant from the National Key Research and Development Program in China,No.2016YFC1101604
文摘Peripheral nerve injury is a serious disease and its repair is challenging. A cable-style autologous graft is the gold standard for repairing long peripheral nerve defects; however, ensuring that the minimum number of transplanted nerve attains maximum therapeutic effect remains poorly understood. In this study, a rat model of common peroneal nerve defect was established by resecting a 10-mm long right common peroneal nerve. Rats receiving transplantation of the common peroneal nerve in situ were designated as the in situ graft group. Ipsilateral sural nerves（10–30 mm long） were resected to establish the one sural nerve graft group, two sural nerves cable-style nerve graft group and three sural nerves cable-style nerve graft group. Each bundle of the peroneal nerve was 10 mm long. To reduce the barrier effect due to invasion by surrounding tissue and connective-tissue overgrowth between neural stumps, small gap sleeve suture was used in both proximal and distal terminals to allow repair of the injured common peroneal nerve. At three months postoperatively, recovery of nerve function and morphology was observed using osmium tetroxide staining and functional detection. The results showed that the number of regenerated nerve fibers, common peroneal nerve function index, motor nerve conduction velocity, recovery of myodynamia, and wet weight ratios of tibialis anterior muscle were not significantly different among the one sural nerve graft group, two sural nerves cable-style nerve graft group, and three sural nerves cable-style nerve graft group. These data suggest that the repair effect achieved using one sural nerve graft with a lower number of nerve fibers is the same as that achieved using the two sural nerves cable-style nerve graft and three sural nerves cable-style nerve graft. This indicates that according to the ‘multiple amplification＇ phenomenon, one small nerve graft can provide a good therapeutic effect for a large peripheral nerve defect.
文摘Previous studies have shown that exogenous gangliosides promote nervous system regeneration and synapse formation. In this study, 10 mm sciatic nerve segments from New Zealand rabbits were thawed from cryopreservation and were used for the repair of left sciatic nerve defects through allograft bridging. Three days later, 1 mL ganglioside solution （1 g/L） was sub- cutaneously iniected into the right hind leg of rabbits. Compared with non-injected rats, muscle wet weight ratio was increased at 2-12 weeks after modeling. The quantity of myelinated fibers in regenerated sciatic nerve, myelin thickness and fiber diameter were elevated at 4-12 weeks after modeling. Sciatic nerve potential amplitude and conduction velocity were raised at 8 and 12 weeks, while conduction latencies were decreased at 12 weeks. Experimental findings indicate that ganglioside can promote the regeneration of sciatic nerve defects after repair with cryopre- served peripheral nerve allografts.
基金supported by a grant from the National Key Basic Research Program of China,No.2014CB542202 and 2014CB542205the National Natural Science Foundation of China,No.30973095&81371354+2 种基金a grant from Science and Technology Project of Guangzhou,in China,No.12C32121609the Natural Science Foundation of Guangdong Province of China,No.S2013010014697 to Guo JSHong Kong SCI Fund to Wu WT
文摘In this study, we developed a novel artificial nerve graft termed self-assembling peptide nanofiber scaffold （SAPNS）-containing poly（lactic-co-glycolic acid） （PLGA） conduit （SPC） and used it to bridge a 10-mm-long sciatic nerve defect in the rat. Retrograde tracing, behavioral testing and histomorphometric analyses showed that compared with the empty PLGA conduit implantation group, the SPC implantation group had a larger number of growing and extending axons, a markedly increased diameter of regenerated axons and a greater thickness of the myelin sheath in the conduit. Furthermore, there was an increase in the size of the neuromuscular junction and myofiber diameter in the target muscle. These findings suggest that the novel artificial SPC nerve graft can promote axonal regeneration and remyelination in the transected peripheral nerve and can be used for repairing peripheral nerve injury.
文摘Nerve fibers are attracted by sutureless end-to-side nerve coaptation into the recipient nerve. Opening a window in the epineurium enhances axon attraction and myeliuation. The authors analyze the features of nerve repair by end-to-side coaptation. They highlight the known mechanisms of axon sprouting and different hypotheses of start up signals （presence or absence of an epineurial window, role of Schwann cells, signaling from the distal trunk）. The clinical literature is also presented and differences between experimental and clinical applications are pointed out. The authors propose their point of view and perspectives deriving from recent experimental and clinical experiences.
基金supported by the National Natural Science Foundation of China,No.81372041(to DW),and No.81801220(to MGZ)
文摘We previously demonstrated that overexpression of tropomyosin receptor kinase A(TrkA)promotes the survival and Schwann celllike differentiation of bone marrow stromal stem cells in nerve grafts,thereby enhancing the regeneration and functional recovery of the peripheral nerve.In the present study,we investigated the molecular mechanisms underlying the neuroprotective effects of TrkA in bone marrow stromal stem cells seeded into nerve grafts.Bone marrow stromal stem cells from Sprague-Dawley rats were infected with recombinant lentivirus vector expressing rat TrkA,TrkA-shRNA or the respective control.The cells were then seeded into allogeneic rat acellular nerve allografts for bridging a 1-cm right sciatic nerve defect.Then,8 weeks after surgery,hematoxylin and eosin staining showed that compared with the control groups,the cells and fibers in the TrkA overexpressing group were more densely and uniformly arranged,whereas they were relatively sparse and arranged in a disordered manner in the TrkA-shRNA group.Western blot assay showed that compared with the control groups,the TrkA overexpressing group had higher expression of the myelin marker,myelin basic protein and the axonal marker neurofilament 200.The TrkA overexpressing group also had higher levels of various signaling molecules,including TrkA,pTrkA(Tyr490),extracellular signal-regulated kinases 1/2(Erkl/2),pErk1/2(Thr202/Tyr204),and the anti-apoptotic proteins Bcl-2 and Bcl-xL.In contrast,these proteins were downregulated,while the pro-apoptotic factors Bax and Bad were upregulated,in the TrkA-shRNA group.The levels of the TrkA effectors Akt and pAkt(Ser473)were not different among the groups.These results suggest that TrkA enhances the survival and regenerative capacity of bone marrow stromal stem cells through upregulation of the Erk/Bcl-2 pathway.All procedures were approved by the Animal Ethical and Welfare Committee of Shenzhen University,China in December 2014(approval No.AEWC-2014-001219).
文摘The hypothesis is that induced pluripotent stem cells (iPSC) derived Schwann cells and/or macrophages can be transplanted into acellular nerve graft in repairing injured nervous system. The efficiency of iPSC seeded acellular nerve graft may mimic the autologous peripheral nerve graft.
