二氢睾酮联合脂肪源性干细胞对小鼠坐骨神经缺损后脑源性神经营养因子及其受体TrkB表达的影响

Effects of DHT and ADSC transplantation on expression of BDNF and its receptor trkB after sciatic nerve injury in mice

目的探讨二氢睾酮(DHT)与脂肪源性干细胞(ADSC)联合应用对小鼠脱细胞同种异体神经支架移植坐骨神经缺损后脑源性神经营养因子(BDNF)及其受体Trk B的表达和功能恢复的影响。方法 30只成年C57BL/6小鼠随机分为脱细胞神经支架(ANA)组、ADSC组和DHT+ADSC组。坐骨神经功能指数(SFI)、电生理和胫前肌湿重比方法检测神经运动功能的恢复,Western印迹检测神经移植体内BDNF及其受体Trk B的蛋白表达。NF200免疫荧光法检测神经支架中轴突表达,并示踪PKH26标记的移植ADSC。结果与ADSC组比较,DHT+ADSC组神经移植体内BDNF和Trk B蛋白相对表达明显增高,NF200表达增强,PKH-26标记的ADSC数量显著增高(P<0.05)。与ANA组比较,ADSC组和DHT+ADSC组电生理波幅明显增高、神经传导速度明显增快、延迟期明显缩短、胫前肌湿重比率明显增高,其中DHT+ADSC组神经恢复作用显著优于ADSC组(P<0.05),而且DHT+ADSC组SFI明显高于ANA组和ADSC组(P<0.05)。结论 DHT联合ADSC移植对小鼠脱细胞异体神经支架修复坐骨神经缺损后轴突再生和功能恢复的作用优于ADSC组,其机制可能与促进神经移植体内BDNF及其受体Trk B表达,进而促进移植的ADSC存活有关。

Objective To study the effect of dihydrotestosterone （DHT） and adipose-derived stem cell （ADSC） transplantation on expression of BDNF, trkB and function recovery after acellular nerve allograft （ANA） repair of the sciatic nerve gap in mice. Methods A total of 30 healthy C57BL/6 mice were randomly divided into ANA group, ADSC group and DHT ＋ ADSC group. The sciatic functions index （SFI）, electrophysiology and the rate of tibialis anterior muscle wet weight were used to evaluate functional recovery. BDNF and trkB protein were evaluated by western boh, observe the protein expression of NF200 and the fluorescence signal of ADSC labeled with PKH-26 in the nerve graft by using immunofluorescence. Results Compared with ANA group, the expression of BDNF, trkB, NF200 and PKH-26 labeled ADSC in DHT ＋ ADSC group were increased （P〈0.05）. Compared with ANA group, nerve conduction velocity, wave amplitude, rate of tibialis anterior wet muscle weight were significantly increased in ADSC group and DHT ＋ ADSC group （ P〈0.05 ）, however, incubation pe- riod were significantly decreased in two treatment group （P〈0.05）, the effect of DHT ＋ ADSC group was more powerful than ADSC group （P〈0.05）, moreover, the SFI score of DHT ＋ ADSC group was higher than ANA group and ADSC group. Conclusions The combined DHT and ADSC transplantation treatment promoted axon regeneration and function recovery significantly more than ADSC treatments, which may be related to DHT upregulating BDNF and TrkB expression in the ANA, and promoting ADSC survival.