Does Resveratrol Play a Role in Decreasing the Inflammation Associated with Contrast Induced Nephropathy in Rat Model?

Abstract

Contrast is widely used in invasive image examinations such as computed tomography (CT) and angiography; however, the risk of contrast-induced nephropathy (CIN) is high. The aim of this study was to investigate the protective effect of resveratrol in a rat model of CIN. Sprague-Dawley rats were divided into four groups: the control group (0.9% saline infusion only); resveratrol group (RSV, resveratrol, 30 mg/kg); contrast media group (CIN); and resveratrol + contrast media group (RCIN, resveratrol 30 mg/kg 60 min before CIN). CIN was induced via an intravenous injection of a single dose of indomethacin (10 mg/kg), one dose of N-nitro-L-arginine methyl ester (10 mg/kg), and a single dose of contrast medium iopromide (2 g/kg). Blood urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin (NGAL) were higher in the CIN group compared to the other groups. Histopathological tubule injury scores were also higher in the CIN group compared to the other groups (p < 0.01). NLPR3 in kidney tissue were higher in the CIN group compared to the other groups; however, these results were improved by resveratrol in the RCIN group compared with the CIN group. The expressions of IL-1β and the percentage of apoptotic cells were higher in the CIN group than in the control and RSV groups, but they were lower in the RCIN group than in the CIN group. The expression of cleaved caspase-3 was higher in the CIN group than in the control and RSV groups, but lower in the RCIN group than in the CIN group. Resveratrol treatment attenuated both injury processes and apoptosis and inhibited the inflammasome pathway in this rat CIN model.

Keywords: contrast induced nephropathy; inflammasome; resveratrol.

Figure 1

Resveratrol attenuated renal injury after exposure to contrast medium. Blood of the control, contrast-induced nephropathy (CIN), resveratrol + contrast media (RCIN), and resveratrol (RSV) groups of rats were collected 24 h after exposure to contrast medium. Serum (A) creatinine, (B) BUN, (C) Serum neutrophil gelatinase-associated lipocalin (NGAL). Data are presented as mean ± standard error (n = 8 per group). *: p < 0.05 versus control; #: p < 0.05 versus RCIN. RSV = resveratrol; CIN = contrast-induced nephropathy; RCIN = resveratrol before contrast-induced nephropathy. Group comparisons were evaluated by ANOVA followed by Tukey’s test.

Figure 2

Histopathological findings of rat kidney after CIN had been induced. Kidney tissues of the CIN and RCIN rats were collected 24 h after contrast nephropathy had been induced. Representative photomicrographs of histologic staining with hematoxylin and eosin in the corticomedullary junction at ×100 (left, A–D) and ×200 magnification (right, E–H). (A and E) Control rats. (B and F) Rats treated with contrast. (C and G) Rats treated with contrast after resveratrol treatment. (D and H) Control rats pretreated with resveratrol. RSV = resveratrol; CIN = contrast-induced nephropathy; RCIN = resveratrol before contrast-induced nephropathy. (I) Histologic scores of contrast nephropathy. Histopathology scoring was assessed in a blinded fashion. The scoring system reflecting the grading of tubular necrosis, loss of brush border, cast formation, and tubular dilatation in 10 randomly chosen, non-overlapping fields (200×) was as follows: 1, <10%; 2+, 10–25%; 3+, 26–75%; and 4+, >75%. The score in the CIN group was 18.3 ± 3.4, compared with 2.5 ± 0.5 in the control group. Treatment with resveratrol (RCIN group) before contrast significantly reduced the histologic injury score to 5.2 ± 1.5 versus RCIN. All statistical analyses were performed by Kruskal-Wallis test, followed by Dunn’s multiple comparison post hoc test (n = 8 for each group). *: p < 0.05 versus control; #: p < 0.05 versus RCIN.

Figure 3

Numeric data of apoptotic renal nuclei are presented. Quantitative analyses of TUNEL-positive cells revealed that pretreatment with resveratrol significantly decreased the number of apoptotic cells by 54.3% in the RCIN group. RSV = resveratrol; CIN = contrast-induced nephropathy; RCIN = resveratrol before contrast-induced nephropathy. All statistical analyses were performed by Kruskal-Wallis test, followed by Dunn’s multiple comparison post hoc test (n = 8 for each group). *: p < 0.05 versus control; #: p < 0.05 versus RCIN.

Figure 4

Western blot analysis of renal NLRP3, IL-1β, and cleaved caspase-3. The expression of renal (A) NLRP3, (B) IL-1β, and (C) cleaved caspase-3 increased after the injection of contrast medium in the CIN group, as assessed by Western blot analysis. Resveratrol significantly suppressed the expressions of cytokines in the RCIN group. *, #: p < 0.05 comparing the two groups. NLRP3 = NLR Family Pyrin Domain Containing 3, CIN: contrast-induced nephropathy, RCIN: pretreatment with resveratrol before CIN, RSV: resveratrol 30 mg/kg iv only.