胆红素对内毒素致急性肺损伤大鼠水通道蛋白1、5表达的影响

目的探讨胆红素对脂多糖所致急性肺损伤大鼠的水通道蛋白1、5是否存在调节作用，探讨其保护作用机制。方法雄性Wistar大鼠18只，随机分为生理盐水对照组（C组）、脂多糖模型组（L组）和胆红素预处理组（B组），每组各6只。每组于造模后4h处死大鼠。测定每组肺湿／干重比值，ELISA法测血清中IL-8含量，肺组织中cAMP含量，免疫组化法测定每组水通道蛋白1、5的表达变化。观察各组肺组织病理改变。结果与模型组（L组）比较，胆红素干预组（B组）的W／D值下降，IL-8含量明显降低，cAMP含量表达上升（P〈0．05），水通道蛋白1、5表达增强（P〈0．05），肺水肿病理改变明显减轻。结论胆红素可能是通过cAMP信号途径调节水通道蛋白1、5表达改善水代谢,减轻肺水肿状态，从而对急性肺损伤具有保护作用。

Effect of bilirubin on lung aquaporin 1 and 5 expression in endotoxin-induced acute lung injury rats

Objective To discuss whether the bilirubin had the regulating effect on aquaporin-1 and aquaporin-5 of rats injured by the acute lung injury caused by the lipopolysaccharide and the protective mechanism. Methods Select ed 18 male rats of wistar, which shall be divided randomLy into control group for normal saline （group C）, model group for lipopolysaccharide （group L） and preconditioning group for bilirubin （group B） with 6 rats respectively. All rats shall be killed after 4 h molding. The wet-to-dry weight ratio of the lung per group was measured, the content of IL-8 in serum and the content of cAMP in lung tissue by ELISA method. The expression change of aquaporin-1 and aquaporin-5 per group was examined by immunohistochemical method and the changes of lung tissue per group was pathologically observed. Results Compared with the model group（group L）, the ratio of wet to dry lung weight and the content of IL-8 was significantly reduced in preconditioning group for bilirubin（group B ）（P 〈 0.05 ）. The content of cAMP and the expression of protein of aquaporin-1 and aquaporin-5 had a increased significantly in group B （P 〈 0.05）, and pathologic change of pulmonary edema was reduced significantly. Conclusion The bilirubin may improved the water metabolism and reduced the pulmonary edema state by regulating the aquaporin-1 and aquaporin-5 expressions to had a protective effect to the acute lung injury.