依托咪酯通过PKC/NF-κB信号通路增加成年大鼠视神经损伤后RGC存活

Etomidate promoting retinal ganglion cells survival after optic nerve transaction in adult rats via inhibition of PKC/NF-κB signaling

目的探讨依托咪酯对成年大鼠视神经损伤后视网膜神经节细胞(retinal ganglion cell,RGC)的保护作用及其机制。方法应用大鼠视神经眶内段切断模型,荧光金逆行标记存活RGC;腹腔注射依托咪酯或玻璃体内注射蛋白激酶C(protein kinase C,PKC)抑制剂G6976干预,应用PepTag非同位素PKC检测试剂盒检测视网膜PKC活性,应用免疫印迹法分析视网膜核转录因子-κB(nuclear factor kappa B,NF-κB)水平。结果依托咪酯显著增加大鼠视神经损伤后7 d RGC存活数量(P<0.05),而且显著降低视网膜PKC活性和NF-κB水平(均为P<0.05)。G6976同样显著增加大鼠视神经损伤后7 d RGC存活数量(P<0.05),联合应用依托咪酯和G6976,其存活RGC数量与单纯应用依托咪酯差异无统计学意义(P>0.05);G6976显著降低视网膜NF-κB水平(P<0.05)。结论依托咪酯可显著增加大鼠视神经损伤后RGC存活数量,其机制可能与抑制PKC/NF-κB信号通路有关。

Objective To investigate the effects of etomidate on retinal ganglion cells（RGC） survival after optic nerve transaction in adult rats and its mechanism.Methods The left optic nerves were transected at 1 mm from the optic disc in adult female SD rats.The rats were treated with etmidate by intraperitoneal injection,PKC inhibitor G6976 by intravenous injection,or with etomidate combined with G6976.The surviving RGC were retrogradely labeled by fluorogold and the surviving RGC were counted in the flat-mounted retinas at 7 days after optic nerve transaction.The activity of membrane protein kinase C（mPKC） and cytoplasmic PKC（cPKC） was measured using the PepTag non-radioactive protein kinase assay kit.The protein expression level of nuclear factor kappa B（NF-κB） were analyzed by Western blotting.Results Etomidate significantly increased the number of surviving RGC at 7 days after optic nerve transaction in adult rats（P〈0.05）,and significantly reduced the retinal PKC activity and retinal level of NF-κB（P〈0.05）.G6976 also significantly increased the number of surviving RGC（P〈0.05）,etomidate combined with G6976 did not significantly increase the number of surviving RGC compared with etomidate（P〉0.05）.Go6976 significantly reduced the retinal level of NF-κB（P〈0.05）.Conclusion Etomidate promotes RGC survival in adult rats after optic nerve transaction in part by inhibiting PKC / NF-κB signaling.