Objective: 

The aims of this study were to investigate the effects of sildenafil citrate (SIL) on tissue integrity, oxidant-antioxidant status and apoptosis in rats with colitis.

Methods: 

Colitis was induced by trinitrobenzenesulphonic acid (TNBS) in 40% ethanol (30 mg/ml; 0.8 ml) given intrarectally to Sprague-Dawley rats. Sildenafil (25 mg/kg/day) was administered after the induction of colitis and the treatment was continued for 7 days. After decapitation, the distal colon was scored and stored for the measurement of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and apoptosis. Oxidant generation was monitored by using chemiluminescence (CL). Blood was collected for tumor necrosis factor (TNF)-a and interleukin (IL)-10 assays.

Results: 

The macroscopic lesion score of the colitis group was reduced by SIL (p<0.01). The increase in colonic MDA along with a concomitant decrease in GSH of the colitis group compared to control group was reversed by SIL (p<0.01 and p<0.001, respectively). Sildenafil also reduced the elevated tissue MPO activity (p<0.001), colonic lucigenin CL level and serum TNF-a levels in the colitis group (p<0.001 and p<0.01, respectively). The serum anti-inflammatory cytokine IL-10 level of the colitis group showed a marked reduction compared to control group (p<0.001). However, SIL treatment did not show a significant effect on this parameter. The colonic apoptotic index of rats with colitis was significantly higher than that of the control animals (p<0.001) and reduced by SIL (p<0.01).

Conclusions: 

Sildenafil is beneficial in rat experimental colitis via the maintenance of oxidant-antioxidant status, prevention of apoptosis, superoxide production and cytokine release.