Role of TXNIP/NLRP3 pathway in renal interstitial fibrosis after renal ischemia-reperfusion injury / 中华急诊医学杂志

ABSTRACT

Objective:To explore the role of thioredoxin interaction protein (TXNIP)/NOD-like receptor protein 3 (NLRP3) pathway in renal interstitial fibrosis induced by renal ischemia-reperfusion injury (IRI) in mice.Methods:Adult male C57BL/6J mice aged 6 to 8 weeks and TXNIP knockout mice with the same genetic background were selected. The wild type mice were divided into the sham operation (Sham) group and renal IRI group. The TXNIP knockout mice were divided into the sham+TXNIP KO group and IRI+TXNIP KO group, with 12 mice in each group. The model of renal ischemia-reperfusion injury was established by clamping bilateral renal pedicles for 45 min and then restoring perfusion. The sham operation model was only dissociated bilateral renal arteries without other treatment. Blood creatinine, urea nitrogen, kidney injury molecule-1 (Kim-1) and neutrophil gelatinase-associated lipocalin (NGAL), blood transforming growth factor-β (TGF-β) and interleukin 6 (IL-6) were measured on the 1st, 7th and 28th days after reperfusion. The renal cortex was taken on the 1st and 28th days for Masson staining, in which the renal tubule-interstitial injury score was obtained. TGF-β and IL-6 mRNA expression were detected by qPCR, TXNIP, NLRP3, Pro-IL-1β, IL-1β and α-SMA protein expression were detected by Western blot, and MDA and SOD levels were detected by ELISA. Homogeneity test of variance was performed before the statistics of normal distribution measurement data, one-way ANOVA was used for the comparison between multiple groups, and LSD- t test was used for the comparison between the two groups. Results:On the 1st, 7th and 28th days after IRI, compared with the sham group, the Scr, BUN, Kim-1, NGAL, TGF-β and IL-6 were increased continuously in the IRI group ( P<0.05). On the 28th day after IRI, large areas of collagen fibers and inflammatory cell infiltration were observed in the renal interstitium of the IRI group. In the IRI group, the scores of renal tubular injury and renal interstitial fibrosis on the 28th day were significantly higher than those on the 1st day (all P<0.05). On the 1st, 7th and 28th days after IRI, compared with the IRI group, the levels of Scr, BUN, Kim-1, NGAL, TGF-β and IL-6 were significantly decreased in the IRI+TXNIP KO group (all P<0.05). On the 1st and 28th days after IRI, compared to the IRI group, the areas of collagen fibers and inflammatory cell infiltration in the renal interstitium of the IRI+TXNIP KO group were decreased. The renal tubule injury score [Day 1, (192.2 ± 62.4) vs. (103.2 ± 49.1); Day 28, (154.3 ± 93.6) vs. (64.3 ± 24.8), both P<0.05] and interstitial fibrosis score [Day 1, (7.3 ± 3.2) vs. (4.8 ± 1.7); Day 28, (12.8 ± 3.9) vs. (2.3 ± 0.8), both P<0.05] were all decreased. The expression of TGF-β, IL-6 mRNA, TXNIP, NLRP3, Pro-IL-1 β, IL-1 β and α-SMA protein in renal cortex were significantly decreased (both P<0.05). In renal cortex, MDA level was decreased and SOD level was increased (all P<0.05). Conclusions:TXNIP/NLRP3 pathway is involved in the development of renal interstitial inflammation and fibrosis after renal ischemia and reperfusion. Knockout or inhibition of TXNIP can inhibit the progression of acute renal injury to chronic renal disease.