鞘内注射胶质细胞源性神经营养因子对大鼠糖尿病神经病理性疼痛的影响

 目的 探讨胶质细胞源性神经营养因子(glail cell line-derived neurotrophic factor,GDNF)对糖尿病神经病理性疼痛(diabetic neuropathic pain,DNP)大鼠行为学的影响及机制。方法 将雄性SD大鼠50只随机分为对照组(N组,10只)、模型组(40只),造模后的模型组再随机分成DNP组(DC组,10只,仅给予10 μl PBS缓冲液)、GDNF治疗组(DG组,10只,注射2 μg GDNF+10 μl PBS缓冲液)。各组大鼠均测造模前,造模后第3、21天,首次给药或PBS缓冲液后第1、3、7、14天的压尾机械阈值(TFT)与热痛缩爪潜伏期(PWL);处死大鼠后,取L_4-6脊髓组织,采用Western blot法测定脊髓背角磷酸化PI3K、p-AKT、磷酸化哺乳动物雷帕霉素靶蛋白(p-mTOR)以及磷酸化核糖体S6蛋白激酶(p-S6K)蛋白表达水平。结果 造模后第21 天,与N组比较,模型组的血糖明显升高(P<0.01),且TFT与PWL也均明显缩短(P<0.01);给药后第14 天,与DC组相比较,DG组TFT和PWL均明显升高(P<0.01),且磷酸化PI3K、p-AKT、p-mTOR、p-S6K表达均明显降低(P<0.01);给药后第14天,与N组相比较,DC组TFT和PWL均明显降低(P<0.01),且磷酸化PI3K、p-AKT、p-mTOR、p-S6K表达均明显升高(P<0.01);给药后第14 天,DG组与N组相比较,在TFT、PWL以及磷酸化PI3K、p-AKT、p-mTOR、p-S6K表达等方面的差异均无统计学意义。结论 鞘内注射GDNF能够减轻大鼠DNP,其机制可能与GDNF通过调控PI3K-AKT信号通路,降低p-AKT表达水平,从而抑制p-mTOR和p-S6K的表达有关。

Effects of intrathecal injection of glial cell-derived neurotrophic factor on diabetic neuropathic pain in rats

Objective To explore the effect of glial cell line-derived neurotrophic factor (GDNF) on the behavior of rats with diabetic neuropathic pain (DNP). Methods Fifty male SD rats were randomly divided into the control group (N group,n=10) and model group(n=40). After modeling, the model group was randomly divided into the DNP group (DC group,n=10,given 10 μl PBS buffer alone) and GDNF treatment group (DG group, n=10,injected with 2 μg GDNF + 10 μl PBS buffer). The rats in each group had their mechanical threshold of tail pressing (TFT) and paw withdrawal latency (PWL) measured before modeling, on the 3rd and 21st days after modeling, and on the 1st, 3rd, 7th, and 14th days after the first injection of GDNF or PBS buffer. After the rats were sacrificed, L_4-6 spinal cord tissues were collected, and the expression levels of phosphorylated PI3K, p-AKT, p-mTOR and p-S6K were determined by Western blot. Results On the 21st day after modeling, the blood glucose of the model group was significantly increased compared with the N group, (P<0.01), while the TFT and PWL were significantly reduced (P<0.01). On the 14th day after administration, the TFT and PWL of the DG group were significantly increased compared with the DC group (P<0.01), but the expressions of phosphorylated PI3K, p-AKT, p-mTOR and p-S6K were significantly decreased (P<0.01). On the 14th day after administration, the TFT and PWL of the DC group were significantly decreased compared with the N group (P<0.01), but the expressions of phosphorylated PI3K, p-AKT, p-mTOR and p-S6K were significantly increased (P<0.01). On the 14th day after the drug, the expressions of TFT, PWL and phosphorylated PI3K, p-AKT, p-mTOR and p-S6K in the DG group were not significantly different from those of the N group. Conclusions Intrathecal injection of GDNF can relieve DNP in rats. The mechanism may be related to GDNF’s inhibition of expressions of p-mTOR and p-S6K by regulating the PI3K-AKT signaling pathway and reducing the expression level of p-AKT.