The influence and mechanism of delayed transplantation of human fetal neural stem cells on locomotor recovery after experimental spinal cord injury in rats

English Keywords:Spinal cord injury  Neural stem cells  Implantation  Functional recovery  Rat

English Abstract:

  【Abstract】 Objective：To discuss the effect and mechanism of delayed transplantation of human fetal neural stem cells（hfNSCs） on the locomotor recovery of spinal cord injury.Method：The hfNSCs were separated，cultured and identified from abortive fetus in vitro.Then rat spinal cord injury（SCI） modelｓ（200-250g，n=28） wｅｒｅ established.At ｔｈｅ　9th day after injury，twenty rats with BBB scores between 4 and 5 were divided randomly into two groups with each group of 10 rats.2μl Dulbecco′s phosphate buffered saline（DPBS） with or without 105 2ｎｄ generation hfNSCs wａｓ　transplanted into the experimental and control groups（injection site：1.5mm lateral of central T10 spinal cord）.BBB score was used to evaluate the locomotor improvement between control and experimental group at the 7th，14th，28th，42th，56th day after transplantation.The expressionｓ of glial fibrillary acidic protein（GFAP），microtubule-associated protein 2（MAP2） and CNPase were evaluated by imｍunohistochemistry to observe the survival and differentiation of hfNSCs in the injured area.At ｔｈｅ　56th day after transplantation，the remyelination of two groups wａｓ evaluated by myelin basic protein（MBP） imｍunohistochemistry and transmission electron microscope.Result：The hfNSCs cultured in vitro expressed Nestin and differentiated into astrocytes[（61.2±1.6）%]，neurons[（27.6±3.4）%] and oligodendrocytes[（6.0±5.5）%] respectively.Experimental group（BBB scores：8.3±1.07 at 28th day and 15.1±1.12 at 56th day） had a better locomotor recovery than control group（BBB scores：7.0±0.98 at 28th day and 9.1±0.96 at 56th day）（P<0.05）.Immunohistochemistry showed presence of hfNSCs and differentiation of them into astrocytes and oligocytes on the 56th day after transplantation，yet no hfNSCs-derived neurons were found at that time.There were more astrocytes in ｔｈｅ　experimental group at the 56th daｙ（1502.31±131.92） than 28th days（628.98±119.31）.The numbers of oligocytes between ｔｈｅ　28th day and ｔｈｅ　56th day had no significant difference.The MBP stain at 56th day showed that hfNSCs-derived oligodendrocytes ｍｉｇｈｔ take part in the remyelination in injured area.According to the results of transmission electron microscope，compared with the control group which had broken and deformed myelin sheath，the experimental group displayed formation of more integrate and continous myelin sheath.Conclusion：Delayed hfNSCs transplantation may improve locomotor recovery by remyelination after SCI in experimental rat.