雌激素对新生大鼠高氧肺损伤的影响

Effects of estrogen in neonatal rats with hyperoxia-induced lung injury

[目的]探讨雌激素对高氧所诱发新生大鼠肺损伤的影响.[方法]选用生后2d、体重为5～10g的新生Wistar大鼠,雌雄不拘,随机分为空气对照组、高氧模型组及雌激素治疗组.将空气对照组新生大鼠暴露在室内空气中,其他各组新生大鼠暴露在90%(体积分数)氧中共14d,雌激素治疗组新生大鼠每日分别腹腔内注射给予雌激素2mg/kg,空气对照组和高氧模型组腹腔内注射给予生理盐水.实验开始第3,7,14天时间点记录各组新生大鼠自然死亡数目,计算死亡率;每组处死10只,取肺组织,在光学显微镜下观察肺组织的病理变化,采用免疫组织化学染色方法观察肺组织中γ干扰素(IFN-γ)的表达.[结果]随着高氧暴露时间的延长,高氧模型组及雌激素治疗组死亡率均呈增高趋势,高氧模型组暴露7 d后开始死亡率迅速升高,而雌激素治疗组死亡率明显降低,相比较差异具有统计学意义(P<0.05).空气对照组IFN-γ无阳性表达,而高氧模型组中的阳性表达在第7天时达到高峰,第14天时明显下降,但仍高于空气对照组;雌激素治疗组中的IFN-γ表达强度在各时间段均明显低于高氧模型组(P<0.01).[结论]雌激素对新生大鼠高氧肺损伤有保护作用.

OBJECTIVE To discusse the effects on hyperoxia-induced lung injury of neonatal rats by estrogen.METHODS 2-day-old and 5—10 g Wistar rats were randomly divided into air control group,hyperoxia model group and estrogen treated group.Air control group was exposed to indoor air,and the rest were exposed to 90%（volume fraction） O2 for 14 days.2-day-old rats in estrogen treated group were received intraperitoneal injection of estrogen（2 mg/kg） per day,rats in air control group and hyperoxia model group received intraperitoneal injection of normal saline.Natural death rate of neonatal rats on 3rd,7th and 14th days from the start were observed.10 rats in each group were executed and their lung tissues were taken out and were observed under a optical microscope.The expression of interferon gamma（IFN-γ） in the lung tissues were detected by immunohistochemistry.RESULTS The death rate of rats in estrogen treated group and hyperoxia model group showed increasing tendency as the exposing time in the air extended.Among them,the death rate in estrogen treated group increased slowly.But the death rate in hyperoxia model group increased rapidly after exposed 7 days in the air and had significant differences compared with that of estrogen treated group（P0.05）.There was no expression of IFN-γ positive cells in air control group,but the expressional intensity level was gradually enhanced as the time of inhaling hyperoxia prolonged in hyperoxia model group.It reached the peak on the seventh day,and then obviously declined on the fourteenth day,but still higher than that of air control group.The expressional intensity level of IFN-γ in estrogen treated group was lower than that of hyperoxia model group in each time segment.It had significant differences among them（P0.01）.CONCLUSION Estrogen have protective effects on lung injury induced by hyperoxia in neonatal rats.