机械通气致大鼠肺损伤时肺组织PPARγ表达的变化

摘要

Objective To observe the changes of PPARγ expression in ventilator-induced lung injury rats and explore the role of PPARγ in the pathogenesis of ventilator-induced lung injury. Methods Sixty male Sprague-Dawley rats were randomly divided into 3 groups ( n=21 each ):group N received large tidal volume with mechanical ventilation ( Vt=12 mL/kg);group C received lower tidal volume with mechanical ventilation ( Vt=6 mL/kg);group R received room air without mechanical ventilation. Rats in every group were randomly divided into 3 subgroups respectively by 1,4 and 8 h. The samples of lung were collected at 1,4 and 8 h after ventilation. Lung pathological examina-tion, total protein and white blood cells in bronchoalveolar fluid and wet-to-dry weight were detected. The exoressions of PPARγmRNA were detected by RTPCR;PPARγ protein in lung tissues was detected by western bolt. Result After 4 and 8 h ventilation in group N,total pro-tein and WBC in bronchoalvelor fluid,W/D were markedly higher than those of group C and R (P <0. 01). While PPARγ mRNA and PPARγ protein were decreased than those of group C and R (P<0. 01). There were no difference after 1 h ventilation in three group (P>0. 05). Conclusion PPARγmRNA and protein expressions in the rats lung tissue of ventilator-induced lung injury were decreased and as-sociated with inflammation and damage of lung tissue.%目的：观察PPARγ在通气相关性肺损伤大鼠肺组织中的表达,探讨PPARγ在通气相关性肺损伤中的作用。方法清洁雄性SD大鼠,随机分为大潮气量( Tidal volume,VT)组,Vt=12 mL；小潮气量组,Vt=6 mL；自主呼吸组。每组又分为3个亚组：即通气1h、4h、8h组。于各时间段末放血处死动物,收集肺组织和肺灌洗液标本,测定肺灌洗液中蛋白总量、白细胞计数；测定肺组织湿/干重比( W/D)；逆转录聚合酶链反应检测PPARγmRNA的表达；western blot检测PPARγ蛋白的变化。结果大潮气量组机械通气4 h、8 h后,与小潮气量组及自主呼吸组相比,肺灌洗液中白细胞计数、蛋白总量明显增加(P <0.01),肺 W/D 增加(P<0.01)；肺组织出现明显病理组织学损伤；PPARγmRNA和PPARγ蛋白表达减少(P<0.01)。通气1 h时,各组之间比较无显著差异(P>0.05)。结论通气相关性肺损伤大鼠肺组织中PPARγ基因和蛋白表达下降,这可能与炎症损伤和持续有关。