The effect of sildenafil on an animal model for ischemic colitis

Sildenafil both enhances vasodilatation by relaxing the smooth muscle in the vessels and inhibits platelet aggregation. We have therefore examined the potential benefits of sildenafil on an animal model for ischemic colitis (IC).

Twenty-eight female Wistar albino rats weighing 250-300 g were randomized into three experimental groups as follows: in Group 1, animals were sham operated (n = 8) and received tap water; in Groups 2 and 3, the rats underwent a standardized surgical procedure to induce IC (n = 10 in each group). Group 2 animals served as the controls, receiving only tap water, while Group 3 animals received 10 mg/kg sildenafil per day as a single dose for a 3-day period. All animals were sacrificed 72 h after devascularization. To determine the severity of the ischemia, we scored the macroscopically visible damage, measured the ischemic area and scored the histopathology. Tissue malondialdehyde levels were also evaluated.

The mean area of ischemic changes were 116.80 +/- 189.93 and 0.55 +/- 1.01 mm2 in Group 2 and 3 animals, respectively (p = 0.0001), while the macroscopically mean visible damage score decreased to 0.66 +/- 0.70 (p = 0.0001) for Group 3 animals. The Chiu scores were 0.00, 3.80 +/- 0.91 and 2.66 +/- 1.00 in Group 1, 2 and 3 animals, respectively. There was a statistically significant difference between Group 2 and 3 animals (p = 0.017).

Our findings support the view that sildenafil leads to a improvement in IC due to its well-known effects on the vascular smooth muscle and on the microcirculatory hemodynamics.