野黄芩素对内毒素血症大鼠急性肺损伤的保护作用

Protective effect of scutellarein on acute lung injury in endotoxemic rats

摘要:

目的  观察野黄芩素对脂多糖诱导的急性肺损伤的保护作用。方法  将大鼠静脉内注射脂多糖（30 mg/kg）以诱导急性肺损伤。1 h后分别静脉注射不同浓度的黄芩素（0.1、0.5和1.0 mmol/kg），酶联免疫吸附试验法检测血浆中肿瘤坏死因子α，白细胞介素6和白细胞介素10的浓度；还原法检测肺组织中亚硝酸盐/硝酸盐的含量；实时定量聚合酶链式反应和蛋白免疫印迹法（Western blot）分别检测一氧化氮合成酶和血红素氧合酶-1 mRNA及蛋白的表达；HE染色观察病理学改变情况。结果  0.5和1.0 mmol/kg的黄芩素能减少大鼠血浆中肿瘤坏死因子α和白细胞介素6含量，并能进一步增加白细胞介素10水平。脂多糖注射后肺组织中一氧化氮合成酶蛋白表达和血浆中一氧化氮含量显著增加，而黄芩素处理后一氧化氮合成酶和一氧化氮水平明显减少。脂多糖能诱导血红素氧合酶-1表达，但黄芩素处理后能进一步上调血红素氧合酶-1表达水平。血红素氧合酶-1抑制剂锡原卟啉处理后可消除黄芩素对细胞因子及一氧化氮合成酶表达的影响。此外，黄芩素还能减少肺组织水肿及中性粒细胞渗出。结论  黄芩素可能通过诱导血红素氧合酶-1表达来减轻脂多糖诱导的急性肺损伤。

Abstract:

Objective To observe the protective effect of scutellarein on acute lung injury (ALI) in endotoxemic rats. Methods Rats were administered LPS (30 mg/kg) by intravenous infusion to induce ALI. Scutellarein (0.1, 0.5 and 1.0 mmol/kg) was given 1 h after LPS initiation. Levels of TNF-α, IL-6 and IL-10 in serum and levels of nitrite/nitrate production were measured by ELISA and reduction method respectively. Expression of the mRNA and protein of iNOS and HO-1 were detected by qPCR and Western blot, respectively. The tissue injury was analyzed by histopathology. Results Scutellarein (0.5 and 1.0mmol/kg) attenuated plasma levels of TNF-α and IL-6 caused by LPS, and increased IL-10 levels compared with the LPS group. At 6 h after LPS initiation, the expression of iNOS protein in lung and the lever of NO in plasma were markedly increased, which were reduced by scutellarein (1.0 mmol/kg). LPS caused a significant HO-1 induction, whereas administration of scutellarein (1.0 mmol/kg) significantly induced higher HO-1 expression compared with the LPS group. The beneficial effects of scutellarein on cytokines and iNOS expression were reversed with HO-1 inhibitor SnPP. The edema and infiltration of neutrophils into lungs was reduced by scutellarein. Conclusions Scutellarein may induce the expression of HO-1 to alleviate LPS-induced ALI.