重组人促红细胞生成素对成年大鼠高氧肺损伤Bax和Bcl-2蛋白表达的影响

Effects of Recombinant Human Erythropoietin on Expression of Bax and Bcl-2 Proteins in Hyperoxia-Induced Lung Injury of Adult Rats

目的探讨重组人促红细胞生成素(rHuEPO)对成年大鼠高氧肺损伤Bax和Bcl-2蛋白表达的影响。方法健康成年雄性SD大鼠48只,随机分为6组,每组8只。对照组吸入空气,设为0 h组;其余5组置入动物实验氧舱吸入100%浓度氧气,分为24 h组、48 h组、72 h组、96 h组和rHuEPO干预组。rHuEPO干预组吸氧时间为96 h,并每日予以rHuEPO1000 U/kg腹腔内注射。颈动脉采血行动脉血气分析,计算氧合指数,测定左肺湿干重比值(W/D)及支气管肺泡灌洗液(BALF)中TNF-α、IL-1β水平,免疫组化及Western blot方法检测肺组织Bax和Bcl-2蛋白表达,并观察肺组织病理学改变。结果随高氧暴露时间延长,大鼠氧合指数逐渐下降,96 h达到最低值;左肺W/D值逐渐增加,96 h达到高峰;BALF中TNF-α、IL-1β水平逐渐增高,48 h达到高峰,此后开始下降;肺组织中Bax蛋白表达逐渐增多,Bcl-2蛋白表达逐渐减少。rHuEPO干预组与96 h组比较,氧合指数增加,左肺W/D值下降,BALF中TNF-α、IL-1β水平下降,Bax蛋白表达减少,Bcl-2蛋白表达增加。结论 rHuEPO能够下调肺组织Bax蛋白表达,上调Bcl-2蛋白表达,抑制肺泡上皮细胞凋亡,从而一定程度上减轻高氧所致成年大鼠急性肺损伤。

Objective To investigate the effects of recombinant human erythropoietin（rHuEPO） on expressions of Bax and Bcl-2 proteins in hyperoxia-induced lung injury of adult rats.Methods Forty-eight healthy male SD adult rats were randomly divided into six groups.The control group（0 h） breathed with room air.The rHuEPO intervention group was put into oxygen chamber and breathed with 100% O2 for 96 h plus intraperitoneal injection of rHuEPO（1000 U/kg）daily.Other four groups were put into oxygen chamber and breathed with 100% O2 for 24,48,72 and 96 h respectively.Arterial blood gases were measured to calculate oxygenation index.Wet-to-dry weight ratios of left lung were measured.The contents of TNF-α and IL-1β in bronchoalveolar lavage fluid（BALF） were assayed with radioimmunoassay.The expressions of Bax and Bcl-2 proteins in the lung were determined with Western blot and immunohistochemisty.The changes of lung histopathology were assessed by hematoxylin and eosin stain and observed under light microscope.Results After breathing 100% O2,the oxygenation index decreased gradually and reached minimal value at 96 h.The wet-to-dry weight ratio of left lung increased gradually and reached maximal value at 96 h.The contents of TNF-α and IL-1β in BALF reached maximal value at 48 h and then decreased gradually.The expression of Bax protein increased,but the expression of Bcl-2 protein decreased gradually in the lung.Compared with the 96 h group,the oxygenation index was higher,wet-to-dry weight ratio and contents of TNF-α and IL-1β in BALF decreased,the expression of Bax protein decreased,and the expression of Bcl-2 protein increased in the lung of the rHuEPO group.Conclusion rHuEPO can attenuate hyperoxia-induced lung injury of adult rats by down-regulating expression of Bax protein and up-regulating expression of Bcl-2 protein.