CTx促进远端视神经切断后视网膜节细胞轴突再生与c-Jun表达的关系

THE RELATIONSHIP BETWEEN PROMOTING EFFECT OF CT_X ON AXON REGENERATION AND C-JUN EXPRESSION IN RETINAL GANGLION CELLS AFTER DISTAL AXOTOMY OF OPTIC NERVE

目的探讨霍乱毒素(CTx)促进成年金黄地鼠视神经远端切断后视网膜节细胞(RGCs)轴突再生与c-Jun的表达关系。方法远端切断视神经并对接一段自体坐骨神经,玻璃体内注射CTx及/或植入小段坐骨神经分支(SN)。动物随机分为AG+CTx组;AG+SN组;AG+SN+CTx组,各组动物分别存活4W,用荧光金(FG)逆行标记和c-Jun免疫荧光组织化学双标法观察轴突再生的RGCs内c-Jun表达情况。结果再生RGCs内有c-Jun蛋白表达,玻璃体内给予CTx或植入SN组RGCs表达c-Jun的再生RGCs分别为35·8±9·57和32·2±7·25个,约占其再生总数的94%及90%,两组相比无显著性差异(P>0·05);CTx与SN联用组c-Jun阳性再生的RGCs为150·2±43·92个,占再生总数的97%,与前两组相比,均有显著性差异(P<0·05)。结论视神经远端切断后约90%以上的再生RGCs有c-Jun表达,提示c-Jun表达与视神经远端受损后节细胞轴突再生密切相关,CTx及外周神经对RGCs轴突再生及c-Jun表达有协同促进作用。

Objective To investigate the relationship between the promoting effect of Cholera toxin on the axon regeneration of the retinal ganglion cells and c-Jun expression in the retinal ganglion cells after distal axotomy of the optic nerve in adult hamsters. Methods After transecting the optic nerve （ON） intracranially, an autologus sciatic nerve （attached graft, AG） was removed and connected to the proximal stump of ON. CTx was injected and/or a 2mm segment of sciatic nerve was inserted introvitreally. The animals were divided into three groups. AG＋-CTx group , AG＋SN group and AG＋SN＋CTx group. All animals survived for 4 weeks. The Flouro-Gold （FG） retrog, rade labeling method and c-jun immunoflourecence labeling method were used to estimate the expression of c-jun in the regenerating RGCs. Results There was c-jun expression in the regenerating RGCs. The number of c-jun positive regenerating RGCs in AG＋CTx and AG＋SN groups were 35.8±9.57 and 32. 2±7. 25, constituting 94. 0% and 90. 7% of the total regenerating RGCs respectively. There was no significant difference between these two groups （P〉0.05） . There were 150.2±43.92 c-jun positive RGCs in the CTx＋SN group and constituted 97.4% of the total regenerating RGCs, which was significant higher than in AG＋CTx and AG＋SN group （P〈0.05）. Conclusion Over 90% regenerating RGCs express c-jun, which indicates that c-jun has a correlation with axon regeneration of RGCs after distal axotomy of the ON. CTx can cooperate with SN to promote the axon regeneration of RGCs and the c-Jun expression.