Nrf2在百草枯中毒致大鼠急性肺损伤中的表达和意义

Significance of Nrf2 expression in acute lung injury induced by paraquat poisoning in rats

目的研究转录因子NF-E2相关因子2(Nrf2)在百草枯中毒致大鼠急性肺损伤(ALI)中的表达和意义。方法 48只SD雄性大鼠随机平均分成百草枯中毒组和对照组。在注射百草枯后4、8、24和72 h时,收集血清和肺组织标本。采用生化法检测血清中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量,采用ELISA检测血清中IL-1β和TNF-α含量,检测大鼠肺湿/干重比,行组织切片HE染色进行肺损伤评分,利用Western blot检测肺组织中Nrf2蛋白表达水平,采用免疫组织化学法检测Nrf2在肺组织中的表达。结果大鼠百草枯中毒后血清中SOD活性降低,MDA含量增加,而炎症细胞因子IL-1β和TNF-α含量均明显增加。肺湿/干重比以及肺损伤呈时间依赖性增加。Nrf2在正常肺组织中有少量表达,当百草枯中毒1 d后其蛋白的表达量明显增加。结论 Nrf2参与了百草枯导致ALI的过程,并产生内在的保护作用。Nrf2有望成为治疗百草枯中毒新的靶点,具有良好的临床应用前景。

【Objective】 To investigate the significance of Nrf2 expression in acute lung injury induced by paraquat（PQ） poisoning. 【Methods】 A total of 48 male Sprague-Dawley rats were equally and randomly assigned to two groups： PQ poisoning group（paraquat 20 mg/kg, ip） and control group（saline 1 ml, ip）. Serum and lung tissues were collected at 4 h, 8 h, 1 d and 3 d after PQ exposure. The levels of MDA and SOD activity were detected by biochemical method. The concentrations of TNF-α and IL-1β were measured by ELISA. The wet-to-dry（W/D） ratios and lung injury scores as well as the protein levels of Nrf2 were also determined. Detection of Nrf2 expression in the lung tissues was conducted by immunohistochemistry. 【Results】 The reduction of SOD activity, the increased levels of MDA and cytokines including TNF-α and IL-1βin the serum of PQ-treated rats were observed compared to the control group. The wet-to-dry（W/D） ratios and lung injury scores were increased time-dependently. The Nrf2 protein was slightly expressed in normal lung tissues and increased on 1 d after PQ exposure. 【Conclusions】 Nrf2 is involved in the development of acute lung injury induced by paraquat and exerts a self-protective effect. Nrf2 may be a potential therapeutic target of paraquat poisoning and presents its prospect in clinical application.