Objectives: To study the possible renoprotective effect of sildenafil against renal ischemia/reperfusion (I/R) injury and its effect on the expression of some antioxidant, antiapoptotic gene and proinflammatory cytokine genes in rat model of renal I/R injury.
Materials and methods: One hundred and twenty male Sprague Dawley rats were subdivided into three equal groups: sham (underwent right nephrectomy without ischemia), control (underwent right nephrectomy and left ischemia for 45 min) and study [as control with 1 mg/kg sildenafil (per oral) 60 min before anesthesia]. Serum creatinine and BUN were measured at the baseline and the study endpoints (2, 24, 48 h and 7 days), and the left kidney was harvested at study endpoints for histopathological examination as well as for assessment of the expression of antioxidant genes (Nrf-2, HO-1 and NQO-1), antiapoptotic gene (Bcl-2) and inflammatory cytokines, e.g., TNF-a, IL-1β and ICAM-1.
Results: I/R caused significant increase in serum creatinine, BUN, histopathological damage score (p < 0.001) and significant reduction in antioxidant genes (nrf2, HO-1 and NQO-1) and antiapoptotic gene (Bcl2) with significant increase in TNF-a, IL-1β and ICAM-1 genes in kidney tissues. Pretreatment with sildenafil caused significant attenuation of serum creatinine and BUN as well as significant increase in the expression of antioxidant genes and Bcl-2 genes with significant reduction in the expression of proinflammatory cytokine genes (p value < 0.001).
Conclusion: The renoprotective effect of sildenafil against renal I/R might be due to the activation of antioxidant genes (Nrf2, HO-1 and NQO-1) and antiapoptotic gene (Bcl2) and attenuation of proinflammatory cytokines (TNF-a, IL-1β and ICAM-1).
Keywords: Bcl-2; HO-1; Ischemia/reperfusion; Kidney; NQO-1; Nrf2; Sildenafil.