依托咪酯对成年大鼠视网膜神经节细胞的差异性保护作用

目的 探讨依托咪酯对成年大鼠视神经损伤后视网膜不同部位视网膜神经节细胞(RGCs)存活的影响.方法 取55只成年雌性SD大鼠,于双侧上丘和顶盖前区及外侧膝状荧光金逆行标记RGCs,然后随机分为6组:正常组(n=5),模型组(n=10),脂肪乳组(n= 10;视神经损伤后腹腔注射等体积脂肪乳,1次/d),以及低、中、高剂...

Differential protective effect of etomidate on retinal ganglion cell survival in adult rats after optic nerve injury

Objective To explore the effect of etomidate on the survival of retinal ganglion cells(RGCs)in different parts of retina in adult rats after the optic nerve injury(ONI).Methods Fifty-five adult SD rats were randomly divided into 6 groups:normal group(n=5),model group(n=10)and vehicle group(n=10;intraperitoneal injection of equal volume lipid emulsion,once a day),and low-,medium-and high-dose etomidate groups(n=30;intraperitoneal injection of etomidate at 2,4,6 mg/kg,respectively;once a day).Five dats after the RGCs labeled by flurogold in bilateral superior colliculus,pretectal region and lateral geniculate bodies,the left optic nerve was transected 1.0 mm from the optic disc,and the RGCs 1,2 and 3 mm from the edge of optic disc(1-,2-and 3-EOD,respectively)were calculated 7 and 14 days wfter the ONI.Results The 1-,2-and 3-EOD RGC densities of normal rats were(2652±116)cells/mm²,(2196±145)cells/mm² and(1758±137)cells/mm²,respectively.Closer to the optic disc,the higher the RGC densities in normal rats(P<0.05).However,the survival rate of 3-EOD RGCs was significantly higher than those of 1-and 2-EOD RGCs 7 and 14 days after the ONI(P<0.05)in model group.Seven days after the ONI,low-dose etomidate significantly increased the survival rate of 1-EOD RGCs(P<0.05),and medium-and high-dose etomidate significantly increased the survival rate of 1-,2-and 3-EOD RGCs(P<0.05).Fourteen days after the ONI,low-and medium-dose etomidate had no significant effect on the survival rate of 1-,2-and 3-EOD RGCs(P>0.05);high-dose etomidate significantly increased the survival rate of 1-EOD RGCs(P<0.05).Conclusions The distribution of rat RGCs in the retina is uneven.Different RGCs have different responses to the ONI,and their sensitivities to etomidate treatment are also different.The closer to the optic disc,the more serious the injury,and the more sensitive to etomidate treatment.The higher the dose of etomidate,the wider the protective range of RGCs and the longer the duration of the effect.