目的 制备高体积分数氧(高氧)诱导新生大鼠慢性肺疾病(CLD)模型,探讨持续吸入高氧对新生大鼠肺组织及成纤维细胞Bax及Bcl-2蛋白表达的影响.方法 足月新生大鼠出生12 h内分别持续吸入氧体积分数为900 mL·L-1的高氧(高氧组)和空气(空气组),于3 d、7 d和14 d随机处死动物后,肺组织取材同时进行肺成纤维细胞的原代培养,应用免疫组织化学半定量法检测其Bax及Bcl-2蛋白水平变化.结果 在肺组织中,高氧组Bcl-2蛋白的表达水平在7 d、14 d有所升高(P<0.001),3 d时表达无变化(P>0.05);而高氧组Bax蛋白的表达水平及Bax/Bcl-2比值在3 d、7 d和14 d均明显高于空气组,且具有时间敏感性(Pa<0.01).在肺成纤维细胞,高氧组3 d、7 d Bcl-2蛋白表达水平无变化(P>0.05),14 d时有所增高(P<0.001),但不如Bax蛋白增加明显;高氧组3 d、7 d和14 d肺成纤维细胞Bax蛋白的表达水平及Bax/Bcl-2比值均明显高于空气组(Pa<0.01).结论 高氧可促进新生大鼠肺组织及成纤维细胞Bax蛋白的表达,从而通过上调Bax/Bcl-2比值促进凋亡发生,参与CLD的发生发展过程.%Objective To provide more information of Bax and Bcl - 2 expression in lung tissue and lung fibroblasts in newborn rats with chronic lung disease(CLD) caused by hyperoxia. Methods Full -term newborn rats were continuously exposed to oxygen (900 mL·L-1)or room air within 12 hours after birth. Lung specimens were obtained and primary culture of lung fibroblasts were made respectively on postnatal days 3,7 and 14. Bcl -2 and Bax were quantitated by immunohistochemistry both in lung tissue and fibroblasts. Results In lung tissue,Bcl - 2 was significantly elevated in the hyperoxia - exposed lungs at 7 and 14 days( P ＜ 0. 001 ), but not at 3 days( P ＞ 0. 05 ). The expressionof Bax and the ratios of Bax/Bcl - 2 were significantly higher in the hyperoxia - exposed lungs from 3 days of age and reached a peak at 14 days( P ＜ 0. 01 ). In fibroblasts, Bcl - 2 was significantly elevated in the hyperoxia groups at 14 days ( P ＜ 0.001 ), but not at 3 and 7 days (P ＞ 0. 05 ). The expression of Bax and the ratios of Bax/Bcl -2 were significantly higher in the hyperoxia groups at 3,7 and 14 days( P ＜0. 01 ). Conclusion Prolonged hyperoxia results in the shifting balance of Bax and Bc1-2 may promote apoptosis of lung fibroblasts and be related to the evolution of the CLD.
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