RESUMO
To examine the effect of silymarin [SM], a mixture of flavonoids and polyphenols extracted from Silybum marianum, on mesenteric ischemia-reperfusion [I-R] injury in a rat model. Fifty rats were randomly divided into 5 groups [n = 10]. Group 1 was sham operated, while groups 2-5 were subjected to mesenteric I-R lasting 1 h. Group 2 received isotonic sodium chloride, group 3 received SM [100 mg/kg/day] for 7 days before I-R, group 4 received SM for 7 days after I-R, and group 5 received SM for 7 days both before and after I-R. The rats were sacrificed by exsanguination in groups 1-3 at the 24th hour and groups 4 and 5 were sacrificed on the 7th day of reperfusion. Blood and intestinal specimens were taken for biochemical and pathological evaluations. Serum superoxide dismutase [SOD] and heat shock protein 70 levels were significantly higher in group 2 [5.24 +/- 1.76 U/l and 261.4 +/- 16.8 ng/ml] compared to the sham group [2.08 +/- 1.76 U/l and 189.9 +/- 28.7 ng/ml] [p < 0.001 and p < 0.0001, respectively]. However, SOD activity and the extent and severity of the histopathological lesions were significantly less in groups 3 [3.11 +/- 1.18 U/l, 1.0 [range 0.0-2.0]], 4 [2.15 +/- 0.87 U/l, 1.0 [range 1.0-3.0]], and 5 [1.80 +/- 0.61 U/l, 0.5 [range 0.0-2.0]], treated with SM, than in group 2 [5.24 +/- 1.76 U/l, 2.0 [range 2.0-3.0]] [p = 0.002, p < 0.001, and p = 0.0001; p < 0.001, p = 0.007, and p = 0.0001, respectively]. Also, TNF- alpha levels were lower in the SM-supplemented groups compared to group 2. Serum thiobarbituric acid-reactive substance concentrations were low in the pre-/posttreatment groups treated with SM compared to group 2. No statistical difference was observed for protein carbonyls between the groups. Our findings suggest that SM therapy may attenuate the oxidative and intestinal damage induced by I-R injuries