Bax/Bcl-2在高体积分数氧致新生大鼠慢性肺疾病肺组织及成纤维细胞中的动态变化

Dynamic Changes of Bax/Bcl-2 Expression in Lung Tissue and Fibroblasts of Neonatal Rats after Inhaling High Concentration Oxygen

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12h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3d、7d和14d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7d、14d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3d、7d和14d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3d、7d 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3d、7d和14d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（P0.001）,but not at 3 days（P0.05）.The expression of 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（P0.01）.In fibroblasts,Bcl-2 was significantly elevated in the hyperoxia groups at 14 days（P0.001）,but not at 3 and 7 days（P0.05）.The expression of Bax and the ratios of Bax/Bcl-2 were significantly higher in the hyperoxia groups at 3,7 and 14 days（P0.01）.Conclusion Prolonged hyperoxia results in the shifting balance of Bax and Bcl-2 may promote apoptosis of lung fibroblasts and be related to the evolution of the CLD.