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
目的观察中药牛膝提取物神经再生素(NRF)对小鼠损伤坐骨神经的修复作用。方法ICR小鼠50只,雌雄各半,行坐骨神经夹伤术,随机分成5组:NRF高、中、低剂量组,弥可保组(阳性对照),生理盐水组(空白对照)。术后每日腹腔注射给药。采用小鼠坐骨...目的观察中药牛膝提取物神经再生素(NRF)对小鼠损伤坐骨神经的修复作用。方法ICR小鼠50只,雌雄各半,行坐骨神经夹伤术,随机分成5组:NRF高、中、低剂量组,弥可保组(阳性对照),生理盐水组(空白对照)。术后每日腹腔注射给药。采用小鼠坐骨神经功能指数(sc iatic function index,SFI)、组织形态学及电镜检查,观察NRF对损伤坐骨神经的影响。结果与空白对照组相比,NRF可显著改善小鼠的坐骨神经功能。超微结构观察表明,实验组有髓神经纤维的髓鞘形态、厚度、成熟度均优于对照组,而变性纤维的数目少于对照组。结论NRF能促进小鼠坐骨神经损伤后的修复及其功能的恢复。展开更多
A previous study has indicated that Krüppel-like factor 7（KLF7）, a transcription factor that stimulates Schwann cell（SC） proliferation and axonal regeneration after peripheral nerve injury, is a promising the...A previous study has indicated that Krüppel-like factor 7（KLF7）, a transcription factor that stimulates Schwann cell（SC） proliferation and axonal regeneration after peripheral nerve injury, is a promising therapeutic transcription factor in nerve injury. We aimed to identify whether inhibition of micro RNA-146 b（mi R-146 b）affected SC proliferation, migration, and myelinated axon regeneration following sciatic nerve injury by regulating its direct target KLF7. SCs were transfected with mi RNA lentivirus, mi RNA inhibitor lentivirus, or KLF7 si RNA lentivirus in vitro. The expression of mi R146 b and KLF7,as well as SC proliferation and migration, were subsequently evaluated. In vivo, an acellular nerve allograft（ANA） followed by injection of GFP control vector or a lentiviral vector encoding an mi R-146 b inhibitor was used to assess the repair potential in a model of sciatic nerve gap. mi R-146 b directly targeted KLF7 by binding to the 30-UTR, suppressing KLF7. Up-regulation of mi R-146 b and KLF7 knockdown significantly reduced the proliferation and migration of SCs, whereas silencing mi R-146 b resulted in increased proliferation and migration. KLF7 protein was localized in SCs in which mi R-146 b was expressed in vivo.Similarly, 4 weeks after the ANA, anti-mi R-146 b increased KLF7 and its target gene nerve growth factor cascade, promoting axonal outgrowth. Closer analysis revealed improved nerve conduction and sciatic function index score, and enhanced expression of neurofilaments, P0（anti-peripheral myelin）, and myelinated axon regeneration. Our findings provide new insight into the regulation of KLF7 by mi R-146 b during peripheral nerve regeneration and suggest a potential therapeutic strategy for peripheral nerve injury.展开更多
Olfactory ensheathing cells(OECs)are promising seed cells for nerve regeneration.However,their application is limited by the hypoxic environment usually present at the site of injury.Exosomes derived from human umbili...Olfactory ensheathing cells(OECs)are promising seed cells for nerve regeneration.However,their application is limited by the hypoxic environment usually present at the site of injury.Exosomes derived from human umbilical cord mesenchymal stem cells have the potential to regulate the pathological processes that occur in response to hypoxia.The ability of OECs to migrate is unknown,especially in hypoxic conditions,and the effect of OECs combined with exosomes on peripheral nerve repair is not clear.Better understanding of these issues will enable the potential of OECs for the treatment of nerve injury to be addressed.In this study,OECs were acquired from the olfactory bulb of Sprague Dawley rats.Human umbilical cord mesenchymal stem cell-derived exosomes(0–400μg/mL)were cultured with OECs for 12–48 hours.After culture with 400μg/mL exosomes for 24 hours,the viability and proliferation of OECs were significantly increased.We observed changes to OECs subjected to hypoxia for 24 hours and treatment with exosomes.Exosomes significantly promoted the survival and migration of OECs in hypoxic conditions,and effectively increased brain-derived neurotrophic factor gene expression,protein levels and secretion.Finally,using a 12 mm left sciatic nerve defect rat model,we confirmed that OECs and exosomes can synergistically promote motor and sensory function of the injured sciatic nerve.These findings show that application of OECs and exosomes can promote nerve regeneration and functional recovery.This study was approved by the Institutional Ethical Committee of the Air Force Medical University,China(approval No.IACUC-20181004)on October 7,2018;and collection and use of human umbilical cord specimens was approved by the Ethics Committee of the Linyi People’s Hospital,China(approval No.30054)on May 20,2019.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
文摘目的观察中药牛膝提取物神经再生素(NRF)对小鼠损伤坐骨神经的修复作用。方法ICR小鼠50只,雌雄各半,行坐骨神经夹伤术,随机分成5组:NRF高、中、低剂量组,弥可保组(阳性对照),生理盐水组(空白对照)。术后每日腹腔注射给药。采用小鼠坐骨神经功能指数(sc iatic function index,SFI)、组织形态学及电镜检查,观察NRF对损伤坐骨神经的影响。结果与空白对照组相比,NRF可显著改善小鼠的坐骨神经功能。超微结构观察表明,实验组有髓神经纤维的髓鞘形态、厚度、成熟度均优于对照组,而变性纤维的数目少于对照组。结论NRF能促进小鼠坐骨神经损伤后的修复及其功能的恢复。
基金supported by the National Natural Science Foundation of China (81371362, 81641125, and 81500629)the Scientific Research Foundation of Heilongjiang Province, China (LC2017040)+1 种基金the Science Fund of Heilongjiang Provincial Health and Family Planning Commission, China (2016357 and 2016385)the Basic Research Operating Expenses Program of Heilongjiang Provincial Universities, China (2017- KYYWFMY0661)
文摘A previous study has indicated that Krüppel-like factor 7（KLF7）, a transcription factor that stimulates Schwann cell（SC） proliferation and axonal regeneration after peripheral nerve injury, is a promising therapeutic transcription factor in nerve injury. We aimed to identify whether inhibition of micro RNA-146 b（mi R-146 b）affected SC proliferation, migration, and myelinated axon regeneration following sciatic nerve injury by regulating its direct target KLF7. SCs were transfected with mi RNA lentivirus, mi RNA inhibitor lentivirus, or KLF7 si RNA lentivirus in vitro. The expression of mi R146 b and KLF7,as well as SC proliferation and migration, were subsequently evaluated. In vivo, an acellular nerve allograft（ANA） followed by injection of GFP control vector or a lentiviral vector encoding an mi R-146 b inhibitor was used to assess the repair potential in a model of sciatic nerve gap. mi R-146 b directly targeted KLF7 by binding to the 30-UTR, suppressing KLF7. Up-regulation of mi R-146 b and KLF7 knockdown significantly reduced the proliferation and migration of SCs, whereas silencing mi R-146 b resulted in increased proliferation and migration. KLF7 protein was localized in SCs in which mi R-146 b was expressed in vivo.Similarly, 4 weeks after the ANA, anti-mi R-146 b increased KLF7 and its target gene nerve growth factor cascade, promoting axonal outgrowth. Closer analysis revealed improved nerve conduction and sciatic function index score, and enhanced expression of neurofilaments, P0（anti-peripheral myelin）, and myelinated axon regeneration. Our findings provide new insight into the regulation of KLF7 by mi R-146 b during peripheral nerve regeneration and suggest a potential therapeutic strategy for peripheral nerve injury.
基金supported by grants from the National Natural Science Foundation of China,No.81872699(to MS)Key project of Shaanxi Province,China,No.2017ZDXM-SF-043(to MS)the Military Medical Science and Technology Youth Development Program,China,No.19QNP061(to CL)
文摘Olfactory ensheathing cells(OECs)are promising seed cells for nerve regeneration.However,their application is limited by the hypoxic environment usually present at the site of injury.Exosomes derived from human umbilical cord mesenchymal stem cells have the potential to regulate the pathological processes that occur in response to hypoxia.The ability of OECs to migrate is unknown,especially in hypoxic conditions,and the effect of OECs combined with exosomes on peripheral nerve repair is not clear.Better understanding of these issues will enable the potential of OECs for the treatment of nerve injury to be addressed.In this study,OECs were acquired from the olfactory bulb of Sprague Dawley rats.Human umbilical cord mesenchymal stem cell-derived exosomes(0–400μg/mL)were cultured with OECs for 12–48 hours.After culture with 400μg/mL exosomes for 24 hours,the viability and proliferation of OECs were significantly increased.We observed changes to OECs subjected to hypoxia for 24 hours and treatment with exosomes.Exosomes significantly promoted the survival and migration of OECs in hypoxic conditions,and effectively increased brain-derived neurotrophic factor gene expression,protein levels and secretion.Finally,using a 12 mm left sciatic nerve defect rat model,we confirmed that OECs and exosomes can synergistically promote motor and sensory function of the injured sciatic nerve.These findings show that application of OECs and exosomes can promote nerve regeneration and functional recovery.This study was approved by the Institutional Ethical Committee of the Air Force Medical University,China(approval No.IACUC-20181004)on October 7,2018;and collection and use of human umbilical cord specimens was approved by the Ethics Committee of the Linyi People’s Hospital,China(approval No.30054)on May 20,2019.
