The effect of silymarin on mesenteric ischemia-reperfusion injury

Abstract

Objective: 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.

Materials and methods: 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.

Results: 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-α 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.

Conclusion: Our findings suggest that SM therapy may attenuate the oxidative and intestinal damage induced by I-R injuries.

Fig. 1

Effects of SM before (group 3), after (group 4), and before and after treatment (group 5) on changes in the production of histopathological lesions 24 h and 7 days after mesenteric I-R injury in rats. *⁴ = This observation belongs to sample 4 which is an outlier.

Fig. 2

Microphotographs present the histopathological findings. Representative photo of the terminal ileum. a Normal intestinal mucosa but presence of edema and vascular congestion within the villous tissue in the sham-operated group. H&E. Scale bar = 20 μm. b Wide disintegration and hemorrhage of the villous tissue at 24 h of reperfusion after 1 h of ischemia in the I-R group. H&E. Scale bar = 50 μm. c Slight edema and vascular congestion in the villous tissue treated with SM prior to I-R. H&E. Scale bar = 50 μm. d Rats that were treated with SM before/after I-R had the lowest degree of edema/inflammatory infiltrates in the villous tissue. H&E. Scale bar = 50 μm.