Objective To observe the effects of different oxygen concentrations on retina in neonatal rat. Methods Fifty six neonatal SD rats were randomly divided into three groups, which were high oxygen group exposed to 75% oxygen ( n =24) ;low oxygen group exposed to 35% oxygen ( n =24) and control group exposed to air( n = 8). The high group and low oxygen group were redivided into three groups respectively. The rats in high oxygen group 1 and low oxygen group 1 were exposed to oxygen for seven days, and the rats in high 2 and low 2 were exposed to oxygen for seven days,then exposed to air for seven days,however the rats in high 3 and low 3 were exposed to oxygen for seven days,then the oxygen concentration was gradually decreased to stop oxygen for seven days. The retinal neovascularization of the rats was observed by HE staining and the concentrations of retinal superoxide dismutase(SOD), malondialdehyde (MDA) were detected for all the groups. Results The retinal neovascularization in high land high 3 groups were significantly higher than that in low 1 and low 3 groups respectively ( P <0. 01 ) .which in high 2 group was significantly higher than that in low 2 group ( P <0. 01 ). There were no significant differences among the low oxygen groups and air groups. The levels of retinal SOD in high 1 and high 2 groups were significantly lower than those in correspondent low oxygen groups and air groups ( P < 0. 01 ) , but there was no significant difference between high 3 and low 3 groups ( P > 0. 05 ). The levels of MDA in high 1 and high 2 groups were significantly higher in all the high oxygen groups than those in correspondent low oxygen groups (in high 1 and high IP < 0.01 ; in high 3 P < 0.05 ) . There were no significant differences between all the low oxygen groups and air groups( P >0.05). Conclusion The high concentration oxygen inhalation can result in free radical damage, furthermore, the rapid stopping of oxygen inhalation after high concentration oxygen inhalation will affect severely the development of retinal vessels in neonatal rats.%目的 观察不同浓度吸氧对新生大鼠视网膜的影响.方法 新生SD大鼠56只,分娩完成后随机分为高氧组24只、低氧组24只、对照组8只,高氧组给予75％浓度的氧气吸入,低氧组给予35％浓度的氧气吸入,对照组于空气中饲养.高氧组与低氧组又随机分为高氧1～3组和低氧1～3组.高氧1、低氧1组于持续吸氧7d后,第8天行视网膜组织病理检查及视网膜超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondialdehyde,MDA)测定；高氧2、低氧2组于持续吸氧7d后,第8天停止吸氧,置于空气中饲养,于第15天分别做上述同样检查；高氧3、低氧3组于持续吸氧7d后,第8天每隔1d打开1个调节孔使吸氧浓度逐渐降低直至停止吸氧,于第15天分别做上述同样检查.对照组生后置于空气中饲养,于第15天做上述同样检查.结果 7组视网膜切片突破视网膜内界膜的新生血管内皮细胞核数目比较,高氧1组高于低氧1组、高氧3组高于低氧3组(P＜0.01)；高氧2组明显高于低氧2组(P＜0.01)；各低氧组与对照组比较差异无统计学意义(P＞0.05).与对照组及相应的低氧组比较,高氧1与高氧2组SOD水平明显减低(P＜0.01),MDA水平明显升高(P＜0.01)；高氧3组与低氧3组及对照组比较,SOD差异无统计学意义(P＞0.05),MDA有所升高(P＜0.05).各低氧组与对照组比较SOD与MDA水平差异无统计学意义(P＞0.05).结论 高浓度吸氧会产生自由基损伤,吸高浓度氧后如迅速停用氧气,会严重影响新生鼠视网膜血管发育.
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