褪黑素对大鼠视网膜缺血再灌注损伤后神经节细胞的保护作用

The neuroprotective effect of melatonin on retinal ganglion cells in rats

目的:探讨褪黑素(melatonin,MT)对大鼠视网膜缺血再灌注损伤(retina ischemia reperfusion injury,RIR)中神经节细胞(retina ganglion cells,RGC)的防护和修复作用。方法:健康SD大鼠24只随机分为A组和B组。两组均利用前房高眼压灌注法制成左眼RIR模型,A组每日给予溶媒(100mL/L无水乙醇生理盐水)1mL/kg ip,B组每日给予5g/L MT1mL/kg ip,直至处死动物。两组按左眼RIR后的存活时间又分为3小组:A1和B1组(损伤后7d),A2和B2组(损伤后14d),A3和B3组(损伤后30d),每组各4只。于处死前7d由双上丘和双外侧膝状体注射30g/L fluorogold(FG)标记双眼RGC,处死日行双眼眼球摘除术,将全视网膜组织铺片置于荧光显微镜下,分鼻上、鼻下、颞上、颞下4个区域作荧光摄影,并输入计算机经图像分析系统计数RGC,计算RGC标识率(即损伤眼RGC数/未损伤眼RGC数)×100%,作统计学分析。结果:A1,A2,A33组RGC标识率分别为77.2%±6.4%,65.5%±7.0%,53.9%±4.4%;B1,B2,B33组RGC标识率分别为81.3%±9.3%,79.8%±8.4%,80.3%±11.1%。结论:大鼠RIR后MT治疗可提高RGC存活率。

AIM： To Investigate the neuroprotective effect of melatonin on retinal ganglion cells （RGC） in rats with ischemia reperfusion injury （RIR）. METHODS： Twenty-four healthy SD rats were randomly divided into two groups： group A and group B. RIR model was induced in the left： eyes by increasing the pressure of the anterior chamber. Group A were treated with 100mL/L alcohol-natrii chloridum 1mL/ （kg·d） i.p., Group B with 5g/L MT 1mIL （kg·d） i.p.. According to the time interval between the left eyes RIR and the sacrifice, both group A and group B were further divided into three subgroups： A1 and B1 （day 7）, A2 and B2 （day 14）, A3 and B3 （day 30）, with 4 rats in each subgroup. Seven days before sacrifice, 30g/L fluorogold was injected into the superior collicuU and geniculata body bilaterally. The eyes were enucleated after the rats was sacrificed, and flat mounts of the retina from beth eyes were prepared on a slide and observed under a fluorescence microscope. Four photos were taken from each of the four quadrants of the retina. The labeled RGC were counted by a computerized image analyzer. The labeled RGC rate was used for statistical analysis （the labeled RGC rate=number of RGC in injured eye / control eye×100%）. RESULTS： In group A, the labeled RGC rates were 77.2%±6.4%, 65.5%±7.0% and 53.9%±4.4% on day 7, 14 and 30. In group B, the labeled RGC rates were 81.3%±9.3%, 79.8%±8.4% and 80.3%±11.1% on day 7, 14 and 30. In group B, which was treated with MT after RIR, the labeled RGC rate was significantly higher than that in group A on day 14 and 30 （LSD test, P〈0.05）. CONCLUSION： MT therapy can increase the survival rate of the RGC in the RIR rats.