Xiang Bing-Qian, Yan Wang-Xin, Lou Guo-Qiang, Gao Hui, Zhou Zhuo-Lin, Wu Yi-Ming, Wang Wan-Tie
Institute of Ischemia/Reperfusion Injury Research, Wenzhou Medical University, Wenzhou 325035, China.
Department of Pathology, Taizhou Hospital, Linhai 317000, China.
Sheng Li Xue Bao. 2019 Apr 25;71(2):301-310.
The aim of this study was to investigate the regulatory role of retinoid X receptor (RXR)-mediated oxidative stress pathway in rat pulmonary ischemia/reperfusion injury (PIRI) and the underlying mechanism. Seventy-seven male Sprague-Dawley (SD) rats were randomly divided into 7 groups (n = 11): control group, sham group, sham+9-cis-retinoid acid (9-cRA, RXR agonist) group, sham+HX531 (RXR inhibitor) group, ischemia/reperfusion (I/R) group, I/R+9-cRA group, and I/R+HX531 group. The unilateral lung I/R model was established by obstruction of left lung hilus for 30 min and reperfusion for 180 min in vivo. The rats in I/R+9-cRA and I/R+HX531 groups were given intraperitoneal injection of 9-cRA and HX531 before thoracotomy. After reperfusion, the left lung tissue was taken to evaluate the lung tissue injury, and the oxidative stress-related indexes of the lung tissue were detected by the corresponding kits. The lung tissue morphology and the ultrastructure of the alveolar epithelial cells were observed by HE staining and transmission electron microscope, respectively. The protein expression of RXR in lung tissue was observed by immunofluorescence labeling method, and the expression level of nuclear factor E2-related factor (Nrf2) protein was detected by Western blot. The results showed that, compared with the sham group, the I/R group exhibited obviously injured lung tissue, decreased SOD activity, increased MDA content and MPO activity, and down-regulated expression level of Nrf2 protein. Compared with the I/R group, the I/R+9-cRA group showed alleviated lung tissue injury, increased activity of SOD, decreased MDA content and MPO activity, and up-regulated expression levels of RXR and Nrf2 protein. The above-mentioned improvement effects of 9-cRA were reversed by HX531 treatment. These results suggest that RXR activation can effectively protect the lung tissue against I/R injury, and the mechanism may involve the activation of Nrf2 signaling pathway, the enhancement of antioxidant level and the reduction of oxidative stress response.
本研究旨在探讨维甲酸X受体（RXR）介导的氧化应激途径在大鼠肺缺血/再灌注损伤（PIRI）中的调节作用及其潜在机制。77只雄性Sprague-Dawley（SD）大鼠随机分为7组（n = 11）：对照组、假手术组、假手术+9-顺式维甲酸（9-cRA，RXR激动剂）组、假手术+HX531（RXR抑制剂）组、缺血/再灌注（I/R）组、I/R+9-cRA组和I/R+HX531组。通过在体内阻断左肺门30分钟并再灌注180分钟建立单侧肺I/R模型。I/R+9-cRA组和I/R+HX531组大鼠在开胸术前腹腔注射9-cRA和HX531。再灌注后，取左肺组织评估肺组织损伤情况，并用相应试剂盒检测肺组织氧化应激相关指标。分别通过HE染色和透射电子显微镜观察肺组织形态及肺泡上皮细胞超微结构。采用免疫荧光标记法观察肺组织中RXR蛋白表达，并用蛋白质免疫印迹法检测核因子E2相关因子（Nrf2）蛋白表达水平。结果显示，与假手术组相比，I/R组肺组织损伤明显，超氧化物歧化酶（SOD）活性降低，丙二醛（MDA）含量和髓过氧化物酶（MPO）活性升高，Nrf2蛋白表达水平下调。与I/R组相比，I/R+9-cRA组肺组织损伤减轻，SOD活性升高，MDA含量和MPO活性降低，RXR和Nrf2蛋白表达水平上调。HX531处理可逆转9-cRA的上述改善作用。这些结果表明，RXR激活可有效保护肺组织免受I/R损伤，其机制可能涉及激活Nrf2信号通路、提高抗氧化水平及降低氧化应激反应。
