Background: Gastrointestinal dysmotility is frequently observed after visceral transplantation. The development of postoperative GI dysmotility is multifactorial with an intricate interaction between inflammatory, hormonal, neurogenic, and humoral components. Several studies have shown an increased expression of proinflammatory cytokines in the gut wall as well as infiltration by polymorphonuclear leukocytes into the muscularis propria after SB manipulation. A number of compounds characterized by an olefin linkage conjugated to a carbonyl group have anti-inflammatory properties. The diuretic, ethacrynic acid (EA), is a compound of this type. Herein, we tested the hypothesis that EA can modulate the development of GI dysmotility after bowel manipulation. Methods: Groups (n=9) of male C57Bl/6 mice underwent surgical manipulation of the small intestine using a pair of cotton-tipped applicators (MAN). Control animals (CONT) did not undergo any surgery or receive treatment. MAN mice were pre- and post-treated with four i.p. doses of PBS (phosphate buffered saline), EA1 (1mg/kg per dose) or EA10 (10mg/kg per dose). Gastrointestinal transit of non-absorbable FITC-labeled dextran (MW 70 kDA; FD70) was assessed by gavaging the mice with the tracer 24 h after operation and assessing FD70 concentration 120 min later in bowel contents from the stomach, 10 equally long segments of small intestine, cecum, and two equally long segments of colon. The geometric center (GC) for the tracer was calculated for each animal. Expression of interleukin-6 and inducible nitric oxide synthase transcripts in ileal muscularis propria was assessed using the semiquantitative reverse transcriptase-polymerase chain reaction. Results: In control animals, the mean (±SE) geometric center for the transit marker was 9.89±0.47, whereas for PBS treated animals was 4.59±0.59 (p<0.05 vs CONT). The GC for pre- post treatment with low (1mg/kg) and high (10mg/kg) doses of ethacrynic acid were 7.23±0.97 and 5.15±0.57, respectively. Compared to PBS, treatment with EA (1mg/kg) significantly decreased manipulation-induced IL-6 and iNOS mRNA expression in the wall of the small bowel. Conclusions: Pre- and post-treatment with EA ameliorates ileus and modulate inflammation in the gut wall induced by bowel manipulation.
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