Effect of brain-derived neurotrophic factor on environmental nutrition and neural differentiation of the transplanted stem cells under hypothermia / 中华创伤杂志

ABSTRACT

Objective To study the effect of brain-derived neurotrophic factor (BDNF) on the environmental nutrition and neural differentiation of the transplanted stem cells under hypothermia.Methods The BDNF gene mediated by liposome was transfected into 293T cell line, and ELISA assay was applied to find the peak time of BDNF expression. When BDNF was highly expressed, the supernatant was collected for establishment of SD rat models of brain injury. The rats were divided into Group A (stem cell transplantation group) and Group B (stem cell transplantation and BDNF group). Rats in both groups were under hypothermia treatment for five days. Four and eight days later ( three days from rewarming), rat brain tissues were obtained to detect the expressions of proliferating cell nuclear antigen (PCNA), nestin, neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) by immunohistochemical method and to detect the apoptosis by in situ hybridization. Finally, the nerve function scores were obtained for evaluation of the nerve function. Results The ELISA showed that the high level of BDNF expression was at 48 to 60 hours after gene transfection. PCNA and nestin were highly expressed, while NES and GFAP showed nil or low level of expression in both groups at the fourth day after hypothermia, with little apoptotic cells especially in the Group B (P ＜0.05). The expressions of PCNA and nestin were decreased, but the expressions of NSE and GFAP were increased at the third day after rewarming. The positive rate of NSE expression in the Group B was much higher and the apoptotic cells were much less compared with the Group A ( P ＜ 0. 05 ). A better nerve score was obtained in the Group B. Conclusion BDNF can enhance the survival rate of the transplanted stem cells and induce their differentiation into neurons under hypothermia.