Shi Huijuan, Yang Dongjing, Huo Zhongkun, Li Yuexia, Guo Wenzhi, Zhang Shuijun
Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China.
Henan Open and Key Laboratory for Hepatobiliary & Pancreatic Surgery and Digestive Organ Transplantation, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China.
Exp Ther Med. 2022 Sep 23;24(5):687. doi: 10.3892/etm.2022.11623. eCollection 2022 Nov.
Brain death (BD) results in injury to organs and induces lung donor dysfunction. Since the 20S proteasome abnormality is associated with a variety of diseases, the present study investigated whether it was involved in lung injury following BD in rats, and the effects of the proteasome inhibitor MG132 on lung injury was also assessed. Rats were assigned to a BD group or a control sham group. The BD group of rats were sacrificed at different time points after BD. Administration of MG132 was performed intraperitoneally 30 min before BD. Arterial blood was drawn to measure the oxygenation index [partial artery pressure of oxygen (PaO)/fractional concentration of inspired oxygen (FiO)]. The right lung was used for staining with hematoxylin and eosin, immunohistochemistry, immunofluorescence, western blotting and RT-qPCR analysis. The left lung was used to measure the wet and dry weights. Rat alveolar macrophages (NR8383) were treated with MG132 and hypoxia/reoxygenation (H/R) and used for western blotting and flow cytometry. The PaO/FiO ratio decreased after BD; the wet/dry weight ratio, histological lung injury score and protein expression of 20S proteasome β1 and inducible nitric oxide synthase (iNOS) gradually increased in rats after BD. Colocalization in the immunofluorescence between 20S proteasome β1 and iNOS was observed. MG132 treatment increased the PaO/FiO ratio and decreased the wet/dry weight ratio, histological lung injury score and protein expression of 20S proteasome β1 and iNOS in rats after BD. MG132 was revealed to increase NR8383 apoptosis after H/R and to upregulate the protein expression levels of p-JNK and cleaved-caspase 3. Overall, the proteasome inhibitor MG132 could effectively reduce lung injury, which may be associated with its ability to inhibit the expression of the proteasome and promote the apoptosis of alveolar macrophages.
脑死亡（BD）会导致器官损伤并引发肺供体功能障碍。由于20S蛋白酶体异常与多种疾病相关，本研究调查了其是否参与大鼠BD后的肺损伤，并评估了蛋白酶体抑制剂MG132对肺损伤的影响。将大鼠分为BD组或对照假手术组。BD组大鼠在BD后的不同时间点处死。在BD前30分钟腹腔注射MG132。抽取动脉血测量氧合指数[动脉血氧分压（PaO）/吸入氧分数（FiO）]。右肺用于苏木精-伊红染色、免疫组织化学、免疫荧光、蛋白质印迹和RT-qPCR分析。左肺用于测量湿重和干重。用MG132和缺氧/复氧（H/R）处理大鼠肺泡巨噬细胞（NR8383），并用于蛋白质印迹和流式细胞术分析。BD后PaO/FiO比值降低；BD后大鼠的湿/干重比值、肺组织学损伤评分以及20S蛋白酶体β1和诱导型一氧化氮合酶（iNOS）的蛋白表达逐渐增加。观察到20S蛋白酶体β1和iNOS在免疫荧光中的共定位。MG132处理可提高BD后大鼠的PaO/FiO比值，并降低湿/干重比值、肺组织学损伤评分以及20S蛋白酶体β1和iNOS的蛋白表达。结果显示，MG132可增加H/R后NR8383细胞凋亡，并上调p-JNK和裂解的半胱天冬酶-3的蛋白表达水平。总体而言，蛋白酶体抑制剂MG132可有效减轻肺损伤，这可能与其抑制蛋白酶体表达和促进肺泡巨噬细胞凋亡的能力有关。
