The effects of HIF-1α overexpression on renal injury, immune disorders and mitochondrial apoptotic pathways in renal ischemia/reperfusion rats

BACKGROUND: Renal ischemia/reperfusion (RI/R) injury are a common pathogenesis of acute kidney injury, which may cause renal parenchyma damage clinically. Hypoxia-inducible factor-1α (HIF-1α) has protective effects on cells in regulating the metabolism, angiogenesis, erythropoiesis, and anti-apoptosis of RI/R injury. However, the specific mechanisms for HIF-1α on RI/R injury are still unclear. This study aims to investigate the effects of HIF-1α overexpression on renal function injury, immune disorder, and mitochondrial apoptosis in RI/R rats. METHODS: The rat model of RI/R injury was set up. The lentivirus (LV) vector of HIF-1α overexpression was constructed, and then the LV was transfected to the model rats. The rats were randomly divided into four groups: the control group, RI/R group, RI/R + LV group, and RI/R + LV-HIF-1α group for later experiments. The mRNA levels of HIF-1α were detected by RT-PCR. Proteinuria, urea nitrogen, and serum creatinine levels were detected using the relative kit. Pathological damage was detected by HE staining. Apoptosis was detected by TUNEL staining. Levels of interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α) and interleukin-10 (IL-10) were detected by ELISA. Western blotting was used to detect the protein levels of HIF-1α, caspase-3, caspase-9, Bax, Bcl-2, and other proteins. RESULTS: Compared with the control group, the mRNA and protein levels of HIF-1α in the RI/R group were increased significantly (P<0.05). Proteinuria, urea nitrogen, serum creatinine levels were increased significantly (P<0.05). The levels of IL-6, IL-1 beta, TNF-α were increased significantly (P<0.05). The ratios of cleaved caspase-3/caspase-3, cleaved caspase-9/caspase-9, and Bax/Bcl-2 were increased significantly (P<0.05). There was a significant increase in apoptosis rate and renal pathological tissue damage (P<0.05). Compared with RI/R+LV group, the mRNA and protein levels of HIF-1α in the RI/R+LV-HIF-1α group were increased significantly (P<0.05). Proteinuria, urea nitrogen, serum creatinine levels were decreased significantly (P<0.05). IL-6, IL-1 beta, TNF-α levels were significantly decreased (P<0.05). IL-10 level was significantly increased (P<0.05). The ratios of cleaved caspase-3/caspase-3, cleaved caspase-9/caspase-9, and Bax/Bcl-2 were significantly reduced (P<0.05), showing that the pathological damage degree and the apoptosis rate was significantly lower. CONCLUSIONS: HIF-1α overexpression has protective effects on renal ischemia-reperfusion rats by improving pathological injury and immune function, reducing the release of inflammatory factors, and the expression of apoptotic proteins.