Role of TXNIP/NLRP3 signaling pathway in renal ischemia-reperfusion injury in diabetic rats

Abstract

Objective To evaluate the role of thioredoxin-interacting protein(TXNIP)/oligomerization domain-like receptor family pyrin domain-containing 3(NLRP3)signaling pathway in renal ischemia-reperfusion(I/R)injury in diabetic rats. Methods Pathogen-free healthy male Sprague-Dawley rats, aged 8-12 weeks, weighing 200-220 g, were used in the study.Diabetes mellitus was induced by intraperitoneal injection of 1% streptozotocin 65 mg/kg and confirmed by blood glucose ≥16.7 mmol/L 3 days later.Twenty-four diabetic rats were divided into 3 groups(n=8 each)using a random number table: sham operation group(group S), renal I/R group(group I/R)and resveratrol(TXNIP inhibitor)group(group R). Resveratrol 10 mg/kg was intraperitoneally injected every day for 7 consecutive days starting from 3rd week after successful establishment of the model in group R. At 4th week after successful establishment of the model, renal I/R was produced by occlusion of bilateral renal pedicles for 25 min followed by reperfusion in anesthetized rats in group R. The animals were sacrificed at 48 h of reperfusion, and renal specimens were obtained for microscopic examination of pathologic changes and for measurement of malondialdehyde(MDA)content, superoxide dismutase(SOD)activity and superoxide anion scavenging capability(using colorimetric method), interleukin-1beta(IL-1β)and IL-18 contents(by enzyme-linked immunosorbent assay), cell apoptosis(using TUNEL)and expression of TXNIP, NLRP3 and caspase-1 in renal tissues(using Western blot). Blood samples were obtained from the left ventricle for determination of serum urea nitrogen(BUN)and creatinine(Cr)concentrations. Results Compared with group S, the serum Cr concentration and apoptosis index were significantly increased, superoxide anion scavenging capability in renal tissues was decreased, and the expression of TXNIP, NLRP3 and caspase-1 was up-regulated in I/R and R groups, and the serum BUN concentration and contents of MDA, IL-1β and IL-18 in renal tissues were increased, the SOD activity was decreased(P<0.05), and the pathological changes of renal tissues were aggravated in group I/R.Compared with group I/R, the serum BUN and Cr concentrations were significantly decreased, the contents of MDA, IL-1β and IL-18 and apoptosis index were decreased, the SOD activity and superoxide anion scavenging capability were increased, the expression of TXNIP, NLRP3 and caspase-1 was down-regulated(P<0.05), and the pathological changes of renal tissues were significantly attenuated in group R. Conclusion The pathophysiological mechanism of renal I/R injury is associated with the activation of TXNIP/NLRP3 signaling pathway in diabetic rats. Key words: Thioredoxins; NLR family, pyrin domain-containing 3 protein; Diabetes mellitus; Kindey; Reperfusion injury