眼镜蛇毒NGF对去部分背根后备用背根节内GAP-43表达的影响

目的 探讨从眼镜蛇毒分离纯化出的神经生长因子(NGF)对去部分背根猫备用背根节(DRG)内生长相关蛋白-43(GAP-43)表达的影响.方法 对45只成年雄性家猫切除一侧L1～L5、L7～S2 DRG,保留L6 DRG及背根,随机分为小剂量蛇毒NGF组(1 μg/kg)、大剂量蛇毒NGF组(2 μg/kg)、生理盐水对照组(0.1 mL/kg),每组15只.术后损伤背髓局部即刻给予蛇毒NGF或生理盐水,分别于术后3、6、12d(存活12d的动物术后第6d再从椎间隙内注射上述剂量蛇毒NGF或生理盐水1次)处死动物.对L6备用DRG作GAP-43免疫组织化学检测,计数各组术侧GAP-43阳性大、中小神经元数量.结果 GAP-43表达主要分布于DRG大神经元的胞核和中小神经元的胞浆.治疗组和对照组术后3d在术侧即可见到GAP-43阳性反应的大、中小神经元,6d达高峰,第12d有所下降;其中,中小神经元的变化尤为明显.治疗组术侧GAP-43阳性中小神经元数量多,反应强,与对照组比较差异有统计学意义(P＜0.01),其中大剂量蛇毒NGF组在各时间点阳性中小神经元的数量增多更为明显,与小剂量蛇毒NGF组相比差异有统计学意义(P＜0.01); 而不同时相各组术侧GAP-43阳性大神经元数量变化不明显.结论 外源蛇毒NGF可能通过上调备用根DRG内中小神经元GAP-43的表达而发挥促进备用根轴突再生出芽的作用; 其再生的强弱与蛇毒NGF的治疗剂量有关.

Effect of NGF, Which Is Isolated and Purified from the Venom of Naja naja atra, on Expression of GAP-43 in Dorsal Root Ganglia Removed Partially from Cat

OBJECTIVE: To investigate the effect of the nerve growth factor (NGF), which is isolated and purified from the venom of Naja naja atra, on expression of GAP-43 in dorsal root ganglia (DRG) removed partially from cat. METHODS: A total of 45 adult male cats (rhizotomy of unilateral L1-Ls, L7-S2 dorsal root, leaving L6 as a spared dorsal root in 45 cats allowed to survive 3 days, 6 days, 12 days respectively) were equally divided into 3 groups based on the dose of using the drug: low-dosage group (1 microg/kg), high-dosage group (2 microg/ kg), normal saline control group (0. 1 mL/kg), with using immunohistochemical reaction to detect the GAP-43 of L6 DRG, count the GAP-43-positive large, medium-small neurons. RESULTS: The results were as follows: After the operation, GAP-43 positive products were mainly distributed in nucleus of large neurons and cytoplasm of medium-small neurons. The expressions of GAP-43 positive products in treatment group and control group were detected at day 3, reached the highest level on the 6th day and began to decrease on the 12th day. The number of GAP-43 positive medium-small neurons of the operated side DRG in treatment group increased more apparently than that of control group, the high-dosage group was significantly (P