Caspase-1 inhibition alleviates acute renal injury in rats with severe acute pancreatitis

摘要

AIM:To assess the effect of inhibition of caspase-1 on acute renal injury in rats with severe acute pancreatitis(SAP).METHODS:Forty-two Sprague-Dawley rats were randomly divided into three groups:healthy controls(HC,n=6),SAP rats treated with saline(SAP-S,n=18),or SAP rats treated with a caspase-1/interleukin(IL)-1β-converting-enzyme(ICE)inhibitor(SAP-I-ICE,n=18).SAP was induced by retrograde infusion of 5%sodium taurocholate into the bile-pancreatic duct.HC rats were subjected to identical treatment and surgical procedures without sodium taurocholate.Rats received an intraperitoneal injection of isotonic saline(SAP-S)or the inhibitor(SAP-ICE-I)at 2 and 12 h after induction of acute pancreatitis.Surviving rats were sacrificed at different time points after SAP induction;all samples were obtained and stored for subsequent analyses.The levels of blood urea nitrogen(BUN)and creatinine(Cr)were measured using automatic methods,and serum IL-1βconcentrations were measured by an enzymelinked immunosorbent assay.Intrarenal expression of IL-1β,IL-18 and caspase-1 mRNAs was detected by RT-PCR.IL-1βprotein expression and the pathologic changes in kidney tissues were observed by microscopy after immunohistochemical or hematoxylin and eosin staining,respectively.RESULTS:The serum levels of BUN and Cr in the SAP-S group were 12.48±2.30 mmol/L and 82.83±13.89μmol/L at 6 h,23.53±2.58 mmol/L and 123.67±17.67μmol/L at 12 h,and 23.60±3.33 mmol/L and125.33±21.09μmol/L at 18 h,respectively.All were significantly increased compared to HC rats(P<0.01for all).Levels in SAP-ICE-I rats were significantly decreased compared to SAP-S rats both at 12 and 18 h(P<0.01 for all).Serum IL-1βlevels in the SAP-S group were 276.77±44.92 pg/mL at 6 h,308.99±34.95pg/mL at 12 h,and 311.60±46.51 pg/mL at 18 h;all significantly higher than those in the HC and SAP-ICE-I groups(P<0.01 for all).Intrarenal expression of IL-1βmRNA was weak in HC rats,but increased significantly in SAP-S rats(P<0.01).ICE inhibition significantly decreased the expression of IL-1βand IL-18 mRNAs(P<0.05 for all vs SAP-S),whereas caspase-1 mRNA expression was not significantly different.Weak IL-1βimmunostaining was observed in HC animals,and marked staining was found in the SAP-S group mainly in renal tubular epithelial cells.IL-1βimmunostaining was significantly descended in SAP-ICE-I rats compared to SAP-S rats(P<0.05).Caspase-1 inhibition had no effect on the severity of kidney tissue destruction.CONCLUSION:The expression of caspase-1-activated cytokines IL-1βand IL-18 plays a pivotal role in acute renal injury in rats with experimental SAP.Caspase-1inhibition improves renal function effectively.