Objective: To investigate the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) in the lung tissue of rats with acute diquat (DQ) poisoning and the distribution of diquat in lungs. Methods: Fifty-four fasted male Wistar rats were randomized into control group (n=6) and exposure group (n=48) . According to the time point, the exposure group was divided into 2 h, 4 h, 12 h, 1 d, 3 d, 7 d, 11 d and 14 d groups with 6 rats in each group. Exposure groups were administered 11.55 mg/kg DQ (1 ml/100 g BW) by single-dose of intragastric administration, while the control group rats were given normal saline. The histopathological changes of lung tissue of rats in each group were observed. The expression of nrf2 in lung tissue was detected by immunohistochemistry, and the diquat concentration in lungs was determined by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS) . Results: In the exposure group, DQ was detected in lungs on 2 hours after poisoning. The concentration of DQ in lung tissue decreased gradually over time, and there was no accumulation in lung tissue. The histopathological changes of lung tissue were not obvious in the early stage of poisoning. The injury was the most serious on the 3rd day, a large number of inflammatory cells could be seen in alveolar cavity and lung stroma, and the pathological injury of lung tissue began to be alleviated on the 7th day. The results of immunohistochemistry showed that Nrf2 was mainly expressed in the nucleus of pulmonery cells. The expression of Nrf2 in the exposure group was significantly higher than the control group. The expression of Nrf2 increased significantly at the 12th hour (P<0.05) , reached the peak on the 3rd day (P<0.05) . There was no difference between the control group and the 14th day (P>0.05) . Conclusion: There was no accumulation of DQ in the lung tissue for a long time, and there was a hysteresis in lung injury induced by redox reaction of DQ. Nrf2 was highly expressed in the lung tissue of rats with acute DQ poisoning, which was correlated with histopathology injury of lung tissue, suggesting that Nrf2 plays an important role in antagonizing acute lung injury induced by DQ.
目的： 探讨核因子NF-E2相关因子（nuclear-factor erythroid 2-related factor 2，Nrf2）在急性敌草快（diquat，DQ）中毒大鼠肺脏中的表达及敌草快在大鼠肺脏中的分布特点。 方法： 选择54只无特定病原体（SPF）级Wistar雄性大鼠随机分为对照组（6只）和染毒组（48只），染毒组根据时间点分为2 h、4 h、12 h、1 d、3 d、7 d、11 d和14 d共8个亚组，每个亚组6只。所有大鼠按1 ml/100 g给予一次性灌胃染毒，对照组给予生理盐水，染毒组给予11.55 mg/ml的DQ溶液（生理盐水配置）。观察各组大鼠肺组织病理变化，用免疫组织化学方法检测肺组织Nrf2的表达，并通过高效液相与质谱联用仪测定肺组织匀浆中DQ的浓度。 结果： 染毒组大鼠肺组织在染毒后2 h即可检测出DQ，浓度为0.157 6 ng/mg，随时间延长DQ在肺组织中的浓度逐渐降低，至染毒后第11天肺组织内未检出，无长时间富积现象。肺组织在中毒早期病理改变不明显，第3天损伤最重，肺泡腔和肺间质可见大量炎性细胞浸润，第7天肺组织病理损伤开始减轻。Nrf2主要表达在肺细胞的细胞核，与对照组比较，染毒12 h亚组大鼠肺组织Nrf2表达量明显升高，差异有统计学意义（P<0.05）。随时间延长大鼠Nrf2表达阳性细胞数量逐渐增加，第3天达高峰（P<0.05），之后逐渐减少，染毒第14天与对照组大鼠肺组织Nrf2表达量差异无统计学意义（P>0.05）。 结论： DQ在大鼠肺组织中无长时间富积，且DQ通过氧化还原反应导致的肺损伤存在滞后现象。Nrf2在DQ中毒大鼠肺组织中高表达，且与肺组织病理损伤情况存在相关性。.
Keywords: Diquat; Lungs; Nuclear factor erythroid 2-related factor 2; Rats; Tissue distribution.