Gli2在顺铂诱导的急性肾损伤肾小管病变中的作用机制研究OA

Objective To investigate the action mechanism of Gli2,a key transcription factor in the Hedgehog pathway,in renal tubular lesions of cisplatin-induced acute kidney injury(AKI).Methods(1)Animal experiments:Male SD rats were randomly divided into a control group(injection with saline)or a model group(single intraperitoneal injection with cisplatin,15 mg/kg).The followings were compared between the two groups:serum creatinine levels before and 1,3,and 5 days after the injection,pathological changes in renal tissues 5 days after the injection,and relative expression levels of mRNAs and proteins of Gli2,Shh,α-SMA,TGF-β1,NGAL,IL-6,IL-18(Hedgehog pathway factors and markers of renal tubular injury and fibrosis)and Caspase7(marker of cell apoptosis)5 days after the injection.(2)Cellular experiments:Impacts of different concentrations of cisplatin(0,12.5,or 25 μmol/L)on relative expression levels of Gli2 mRNA and and Gli2 protein in NRK-52E cells were analyzed after the 24-hour intervention.Concentration was chosen to build cell models for subsequent experiments based on the abovementioned concertration gradient tests'results.The rat renal tubular epithelial cells,NRK-52E,were divided into a silent empty vector control group(treated with 12.5 μmol/L cisplatin for 24 hours)or a Gli2-silenced group(using the shRNA method).The relative expression levels of mRNAs and proteins of Gli2,NGAL,Smo,TGF-β1,α-SMA(Hedgehog pathway factors and markers of renal tubular injury and fibrosis),as well as Bax and Caspase7(markers of cell apoptosis),were compared between the two groups of NRK-52E cells.Results(1)Animal experiments:The model group showed higher serum creatinine levels than the control group 1,3,and 5 days after the injection(all P<0.05),and the level increased in a time-dependent way.Renal histopathology showed typical characteristics of renal tubular lesions,including exposure of the basilar membrane due to epithelial cell shedding,interstitial infiltration by inflammatory cells,vacuolar degeneration,and fibrotic changes.After 5 days of injection,the relative expression levels of Gli2,Shh,α-SMA,TGF-β1,NGAL,IL-6,IL-18,and Caspase7 mRNAs and proteins in the renal tissues of rats in the model group were all higher than those in the control group(all P<0.05).(2)Cell experiment:With the increase of cisplatin intervention concentration,the relative expression levels of Gli2 mRNA and Gli2 protein in NRK-52E cells gradually increased(all P<0.05).After 24 hours of intervention with cisplatin at a concentration of 12.5 μmol/L,the relative expression levels of Gli2,NGAL,Smo,TGF-β1,α-SMA,Bax,and Caspase7 mRNAs and proteins in the NRK-52E cells of the Gli2-silenced group,as well as the early apoptosis rate,late apoptosis rate,and total apoptosis rate of the NRK-52E cells,were all lower than those in the silent empty vector control group(all P<0.05).Conclusion The Hedgehog/Gli2 pathway is activated in cisplatin-induced AKI.Gli2 mediates renal tubular epithelial cell injury,apoptosis,and fibrosis in AKI by regulating the activity of the Hedgehog/Gli2 pathway.Gli2 inhibitors are expected to become effective drugs for treating AKI fibrosis and blocking its chronic transformation.