博莱霉素对大鼠肺泡Ⅱ型上皮细胞功能的损伤

目的探讨博莱霉素(BLM)对肺泡Ⅱ型上皮细胞(AT-Ⅱ)功能的损伤作用.方法向SD大鼠气管内一次性注入BLM复制肺纤维化模型,对照组注人生理盐水,分别于7、14和28 d在1.5%戊巴比妥钠麻醉下行支气管肺泡灌洗,膜天平法测定肺表面物质(PS).活性.不同浓度博莱霉素直接刺激培养正常成年大鼠的AT-Ⅱ,荧光定量(FQ)PCR检测AT-Ⅱ表面活性物质蛋白(SP)A、B及水通道蛋白(AQP2)mRNA的表达.结果7 d模型组动物出现低氧血症及PS活性明显降低;14 d逐渐好转,但仍然低于正常;28 d基本恢复正常.BLM刺激AT-Ⅱ组与空白对照组比较,SP-A、SP-B及AQP1 mRNA表达均明显降低(P＜0.001).结论博莱霉素具有细胞毒性,可降低AT-Ⅱ分泌的SP-A、SP-B及AQP1 mRNA的表达,使PS系统功能异常,从而导致低氧血症及肺水肿的发生.

Rat alveolar type II injured by bleomycin

OBJECTIVE: To explore dysfunction mechanism of rat alveolar type II (AT-II) injured by bleomycin (BLM). METHODS: SD rats were injected with a single intratracheal dose of bleomycin or control saline. On day 7, 14, and 28 following intratracheal bleomycin or saline instillation, animals were killed under overdose of 1.5% sodium pentobarbital (0.25 ml/100 g, i.p.) and bronchoalveolar lavage fluid (BALF) from the lung was tested for the activity of pulmonary surfactant (PS) by the Whihelmy Film Balance. Several concentrations of bleomycin stimulated the culture of rat AT-II cells, and surfactant protein (SP) A, B, and aquaporin-1 (AQP) mRNA were analyzed by fluorescent quantitative polymerase chain reaction (FQ-PCR). RESULTS: The activity of PS and hypoxemia significantly decreased on day 7 and improved on day 14 and completely recovered to normal status on day 28. SP-A, B, and AQP-1 mRNA expression in BLM-stimulated group were significantly lower than those in the control group (P<0.001). CONCLUSION: BLM-injured AT-II cells decrease the levels of SP-A, B, and AQP-1 mRNA and cause PS dysfunction, resulting in hypoxemia and pneumonedema.