再生小室内间断给予蛋白激酶C激动剂对周围神经表达NGF及损伤修复的影响

目的探讨大鼠坐骨神经再生小室内间断给予蛋白激酶C激动剂-佛波醇酯(phorbol-12-myristate-13-acetate,PMA)后,坐骨神经蛋白激酶C(protein kinase C, PKC)mRNA、神经生长因子(nerve growth factor, NGF)mRNA表达变化规律及轴突数目变化. 方法 SD大鼠42只行双侧坐骨神经中段切断约5 mm,"T"形硅胶管套接,随机分为6组,分别为损伤1、3天,1、2、3和4周组.右侧间断给予1×10-9mol/L PMA(PMA侧);左侧注射等量生理盐水(对照侧).采用组织切片核酸原位杂交(in situ hybridization,ISH)技术检测各组术后各不同点PKC mRNA和NGF mRNA在坐骨神经表达的动态变化及轴突数目变化. 结果对照侧大鼠坐骨神经PKC mRNA在损伤后表达上调,第2周达高峰后下降;NGF mRNA在损伤后表达上调,第3周达高峰值后下降.PMA侧PKC mRNA于第2、3和4周表达较对照侧明显增高,差异有统计学意义(P＜0.01或P＜0.05);NGF mRNA第2、3和4周表达也较对照侧明显增强,差异有统计学意义(P＜0.01).轴突数目在2、3和4周时多,差异有统计学意义(P＜0.01). 结论 PKC介导了周围神经损伤修复中的NGF mRNA表达及神经再生,而且PMA能够促进NGF mRNA表达及促进轴突生长.

EXPRESSION OF NERVE GROWTH FACTOR mRNA AND NERVE REGENERATION AFTER DISCONTINUOUS INJECTION OF PHORBOL-12-MYRISTATE-13-ACETATE INTO SILICONE CHAMBER

OBJECTIVE: To study the mRNA expressions of protein kinase C(PKC) and nerve growth factor (NGF) in rat sciatic nerve and the number of axons after phorbol-12-myristate-13-acetate (PMA) was injected into silicone chamber. METHODS: Forty-two SD adult rats were divided into six groups depending on the time of injury (1 day, 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks). A 0.5 cm nerve was cut in double rat sciatic nerves and "T" type silicone chamber was sutured. PMA at the concentration of 1 x 10(-9) mol/L was injected discontinuously into the right side of T type silicone chamber (PMA group) and saline was injected into the left side (control group). Nucleic acid in situ hybridization histochemistry technique and the computer imagine analysis were employed to detect dynamic changes of PKC mRNA and NGF mRNA in rat sciatic nerves. The number of axons was measured. RESULTS: The expressions of PKC mRNA and NGF mRNA increased after injury, and the expressions of PKC mRNA and NGF mRNA reached the peak 2 weeks and 3 weeks after injury respectively in control group. The expressions of PKC mRNA and NGF mRNA in PMA group were significantly increased than those in control group 2,3 and 4 weeks after injury (P < 0.01). The number of axons in PMA group significantly increased than that in control group (P < 0.01). CONCLUSION: PKC involved in the expression of NGF mRNA and nerve regeneration after injury. During the regenerated course, PMA can promote the expression of NGF mRNA and the number of axons after injury.