Abstract:

Objective　To explore the molecular mechanism of dynamin-related protein 1 (Drp1) -mediated mitochondrial energy metabolism involved in renal ischemia-reperfusion injury. Methods　The experiment was conducted on October 14, 2020. Male Wistar rats aged 8-10 weeks were randomly divided into a normal control group, a sham operation group, a model group, and a Drp1 inhibitor group, with 5 rats in each group and weight of 0.25-0.30 kg for each rat. The rat model of acute renal injury induced by renal ischemia-reperfusion was established. The rats in the Drp1 inhibitor group were intraperitoneally injected with mitochondrial division inhibitor 1 (Mdivi-1) of 20 mg/kg body weight, and the other groups were injected with normal saline of the same volume. Serum and kidney tissue were retained 24 hours after the model was made. The serum creatinine level, pathological change of renal tissue, apoptosis of renal tissue cells, mitochondrial ultrastructure, and mitochondrial ATPase activity were compared between the groups. The HK-2 cell hypoxia and reoxygenation models were established in vitro. The changes of mitochondrial membrane potential were detected by JC-1 staining after treatment. Analysis of variance was used. Results　Compared with those in the sham operation group, the serum creatinine in the model group was significantly increased [(41.12±1.895) µmol/L vs. (48.68±2.065) µmol/L], the renal tubule injury score was increased [(1.29±0.426) points vs. (6.50±0.577) points], the number of apoptosis in renal tissue was increased [(2.40±0.547) vs. (10.20±1.095)], the mitochondrial damage was more obvious under electron microscope, and the activity of mitochondrial ATPase was decreased [(6.38±0.321) U/mg prot vs. (4.18±0.198) U/mg prot]; in the HK-2 cell hypoxia and reoxygenation models, the proportion of cells with decreased mitochondrial membrane potential increased in the model group compared with that in the sham operation group [(9.81±0.251)% vs. (4.24±0.598)%], with statistically significant differences (all P<0.05). Compared with those in the model group, the serum creatinine in the Drp1 inhibitor group was decreased [(48.68±2.065) µmol/L vs. (43.28±0.895) µmol/L], the renal tubule injury score was decreased [(6.50±0.577) points vs. (4.50±0.578) points], the number of apoptosis of renal tissue cells was decreased [(10.20±1.095) vs. (6.60±1.140)], the mitochondrial structure damage was reduced, and the activity of mitochondrial ATPase was increased [(4.18±0.198) U/mg prot vs. (5.16±0.628) U/mg prot]; in the HK-2 cell hypoxia and reoxygenation models, the proportion of cells with decreased mitochondrial membrane potential decreased in the Drp1 inhibitor group compared with that in model group [(5.90±0.360)% vs. (9.81±0.251)%], with statistically significant differences (all P<0.05). Conclusion　Selective inhibition of Drp1 can effectively improve the energy metabolism disorder, reduce the cell apoptosis, and alleviate the renal ischemia-reperfusion injury by inhibiting the mitochondrial division.

Key words:

Ischemia-reperfusion injury, Mitochondrial division inhibitor, Energy metabolism, Apoptosis, Animal  , experiment

摘要：

目的　探讨线粒体动力相关蛋白1（Drp1）介导线粒体能量代谢参与缺血再灌注肾损伤的分子机制。方法　实验时间2020年10月14日。8～10周龄雄性Wistar大鼠随机分为正常对照组、假手术组、模型组和Drp1抑制剂组，每组5只，每只体质量为0.25～0.30 kg。通过手术建立大鼠肾脏缺血再灌注急性肾损伤模型，Drp1抑制剂组大鼠腹腔注射线粒体分裂抑制剂（mitochondrial division inhibitor 1，Mdivi-1）20 mg/kg体质量，其余各组大鼠注射等体积生理盐水，造模24 h留取血清及肾脏组织。比较组间大鼠血肌酐水平、肾组织病理学改变、肾组织细胞凋亡情况、线粒体超微结构、线粒体ATP酶活力，并建立体外HK-2细胞缺氧复氧模型，经处理后JC-1染色法检测细胞线粒体膜电位变化。采用方差分析。结果　与假手术组比较，模型组大鼠血肌酐明显升高［（41.12±1.895）µmol/L比（48.68±2.065）µmol/L］，肾小管损伤评分升高［（1.29±0.426）分比（6.50±0.577）分］，每高倍镜视野下大鼠肾组织细胞凋亡数量增加［（2.40±0.547）个比（10.20±1.095）个］，电镜下线粒体损伤更明显，线粒体ATP酶活力降低［（6.38±0.321）U/mg prot比（4.18±0.198）U/mg prot］，HK-2细胞缺氧复氧模型中，模型组较假手术组线粒体膜电位降低的细胞比例增多［（9.81±0.251）%比（4.24±0.598）%］，差异均有统计学意义（均P<0.05）。与模型组相比，Drp1抑制剂组大鼠血肌酐下降［（48.68±2.065）µmol/L比（43.28±0.895）µmol/L］，肾小管损伤评分降低［（6.50±0.577）分比（4.50±0.578）分］，每高倍镜视野下大鼠肾组织细胞凋亡数量减少［（10.20±1.095）个比（6.60±1.140）个］，线粒体结构损伤减轻，细胞线粒体ATP酶活力增加［（4.18±0.198）U/mg prot比（5.16±0.628）U/mg prot］，HK-2细胞缺氧复氧模型中，Drp1抑制剂组较模型组线粒体膜电位降低的细胞比例减少［（5.90±0.360）%比（9.81±0.251）%］，差异均有统计学意义（均P<0.05）。结论　选择性抑制Drp1可通过抑制线粒体分裂，有效改善能量代谢障碍，减少细胞凋亡，减轻肾缺血再灌注损伤。

关键词:

缺血再灌注肾损伤, 线粒体分裂抑制剂, 能量代谢, 细胞凋亡, 动物实验