【摘要】 目的:观察N-甲基-N-亚硝脲(N-m ethyl-N-n itrosourea,MNU)对SD大鼠视网膜光感受器细胞的毒性作用。方法:出生后50 d的SD大鼠84只,随机抽取4只作为正常对照组,余下80只分为4组,每组20只,分别按体质量一次性腹腔注射MNU 80、60、40和30 mg/kg。各组每次4只分别于12 h、24 h、48 h、72 h、120 h行右眼闪光视网膜电图检查(ERG),并于造模后1 d、2 d、3 d、5 d、7 d处死动物,取眼球做组织学检查。结果:1)显示正常对照组的大鼠ERG波形清晰,a、b波振幅正常。MNU 80、60、40和30 mg/kg剂量组a波消失时间分别为3 h、12 h、24 h、120 h;b波消失时间分别为12 h、24 h、72 h、168 h。2)形态学检查测到正常组大鼠中心视网膜的外视网膜厚度为(98.4±1.8)μm。MNU处理后5 d和7 d,80、60、40和30 mg/kg剂量组外视网膜厚度分别为0μm、(9.5±2.3)μm、(42.8±2.7)μm、(71.3±2.4)μm和0μm、0μm、(20.8±2.5)μm、(62.9±2.0)μm,其损伤程度和剂量及时间成正比。结论:MNU可选择性地诱导视网膜光感受器细胞发生凋亡,该作用呈剂量和时间依赖性。更多还原

【Abstract】 Aim: To observe the toxic effect of N-methylNnitrosourea(MNU) on photoreceptor cells within retina of SD rats.Methods:Eighty-four 50-day-old SD rats were used throughout the study.Four of them were used as control.The other 80 were randomly divided into four groups(group A,B,C and D),20 rats each.These animals were intraperitoneally injected with MNU at different dosage of 80 mg/kg,60 mg/kg,40 mg/kg and 30 mg/kg,respectively.Each time,4 rats of every group were detected by electroretinograms(ERG) at 12 h,24 h,48 h,3 d,and 5 d after the injection.The rats were sacrificed at 24 h、48 h、3 d、5 d and 7d after the injection respectively.The eyeballs were immediately enucleated for histological observation.Results:1.For group A,B,C and D,the a-wave of ERG vanished at 3 h,12 h,24 h and 5d after the injection of MNU,then did the b-wave,at 12 h,24 h,3 d and 7 d.2.Morphological examination: The retinal thickness of outer nuclear layer and photoreceptor cells in control group was(98.4±1.8) μm.At 5 days post-injection,total retinal thickness of outer nuclear layer and photoreceptor cells in group A,B,C and D were 0 μm,(9.5±2.3) μm,(42.8±2.7) μm and(71.3±2.4) μm respectively.At 7 days post-injection,the figures were 0μm,0 μm,(20.8±2.5) μm and(62.9±2.0) μm,respectively.Conclusion:MNU may selectively lead to the potoreceptor cell apoptosis,which is dose and time-dependent.更多还原