Protective effects of mitochondria-targeted antioxidant SKQ1 on mice with lipopolysaccharide-induced acute renal injury

WAN Yuhan; YANG Dingping

doi:10.3969/j.issn.1002-266X.2024.34.009

Abstract：Objective To observe the protective effect of mitochondria-targeted antioxidant SKQ1 on mice with acute kidney injury(AKI)and to analyze its mechanism.Methods Twenty-four healthy male C57BL/6 mice were ran-domly divided into four groups:the control group,SKQ1-treated group(SKQ1 group),lipopolysaccharide-treated group(LPS group),and LPS-induced SKQ1-treated group(LPS+SKQ1 group),with six mice in each.AKI models were estab-lished by intraperitoneal injection(i.p.)of LPS(10 mg/kg).Mice in the control group received i.p.of normal saline.In the SKQ1 group,mice were intraperitoneally injected with 0.2 mg/kg SKQ1 dissolved in vehicle(10%DMSO,40%PEG300,5%Tween-80,and 45%normal saline);mice in the LPS+SKQ1 group were intraperitoneally injected with SKQ1 at 24 h before modeling;mice were sacrificed at 24 h after AKI induction,and the blood and kidneys were col-lected.Renal pathologic changes were assessed by HE staining and histopathological changes were quantified using the Paller score.Serum creatinine(SCr)and blood urea nitrogen(BUN)were measured using an automated biochemical ana-lyzer.The mRNA expression levels of inflammatory factors,such as interleukin(IL)-1β,IL-6 and tumor necrosis factor-α(TNF-α)in the renal tissues were measured by qRT-PCR.The levels of oxidative stress biomarkers,such as glutathione perocidase(GPx),superoxide dismutase(SOD)and malondialdehyde(MDA)were detected by enzyme-linked immuno-sorbent assay(ELISA).The protein expression levels of apoptosis-related markers,including B-cell lymphoma 2(Bcl-2),Bcl-2-associated X protein(Bax)and Cleaved caspase-3 were analyzed by Western blotting.The mitochondrial struc-tures of the renal tubules in mice of each group were observed by electron microscopy.Results Compared with the con-trol group,mice in the LPS group exhibited more severe kidney pathological damage;specifically,serum levels of SCr and BUN,the scores of kidney tissue damage,and the mRNA levels of inflammatory cytokines IL-1β,IL-6 and TNF-α,as well as the protein expression levels of Bax,Cleaved caspase-3 significantly increased,the protein expression of Bcl-2 and the activities of GPx and SOD decreased,and the content of MDA increased;irregular swelling of mitochondria along with fractured and vacuolization was observed(all P<0.05).Compared with the LPS group,the LPS+SKQ1 group showed a marked reduction in kidney pathological damage,and the serum levels of SCr and BUN,the scores of kidney tissue dam-age,and the mRNA levels of inflammatory cytokines IL-1β,IL-6 and TNF-α,as well as the protein expression levels of Bax,Cleaved caspase-3,and the content of MDA decreased,the protein expression of Bcl-2 and the activity of GPx and SOD increased(all P<0.05);mitochondrial swelling,fractured and vacuolization were alleviated in the LPS+SKQ1 group.Conclusion SKQ1 pretreatment protected against LPS-induced acute kidney injury via reducing inflammation,modulating apoptosis,decreasing levels of oxidative stress and maintaining the normal mitochondrial morphology.