Mitochondria targeted peptide SS-31 prevent on cisplatin-induced acute kidney injury via regulating mitochondrial ROS-NLRP3 pathway

This study aimed to assess the effect and mechanism of SS31 on cisplatin-induced acute kidney injury (CP-AKI) both in vivo and in vitro. Male mices and HK-2 cells were treated using cisplatin to establish models of CP-AKI. 32 C57BL/6 mices were randomly divided into four groups (control group, CP group, CP + normal saline group, CP + SS-31 group). Cisplatin was intraperitoneally injected once to the mice (25 mg/kg). SS31 was administrated for 10 days at dosages of 10 mg/kg per day. Kidney histological changes and level of reactive oxygen species(ROS) were detected. In vitro studies, HK-2 cells were incubated with cisplatin (50 u M) or combimed with SS-31(100 u M), the level of mitochondrial ROS, apoptosis rate and the the expression of NLRP3, Caspase-1 and IL-1β were tested. Renal tubulointerstitial apoptosis and oxidative stress were significantly increased in CP-AKI mice. Cisplatin caused elevation of serum creatinine (Scr), blood urea nitrogen (BUN) levels and enhanced IL-1β, caspase1 and NLRP3 expression, the electron microscopy examination showed mitochondria cristae swelling, mitochondrial spheres and partial ridge breakdown in renal tubular cell of CP-AKI mice. SS31 treatment could effectively suppress mitochondrial ROS, ameliorate these lesions and decrease the expression of NLRP3, IL-1β and Caspase1. In vitro studies, SS31 could restored the level of mitochondrial ROS and downregulate apoptosis rate in HK-2 cells, moreover, the elevated expression of NLRP3, IL-1β and Caspase-1were restored. SS31 could protect CP-AKI in mices, which might be due to an anti-oxidative and anti-apoptotic action via regulating mitochondrial ROS-NLRP3 pathway. NLRP3 inflammasome might be considered as a novel therapeutic target of CP-AKI.