Changes in expression of intestinal microRNAs during intestinal ischemia-reperfusion in rats

Abstract

Objective To investigate the changes in the expression of intestinal microRNAs(miRNAs)during intestinal ischemia-reperfusion(I/R)in rats. Methods Twelve adult male Sprague-Dawley rats, weighing 230-250 g, were randomly divided into 2 groups(n=6 each)using a random number table: sham operation group(group S)and I/R group.Intestinal I/R was induced by 60 min occlusion of superior mesenteric artery followed by 120 min reperfusion in group I/R.At the end of reperfusion, the intestinal specimens were obtained for microscopic examination of pathological changes which were graded using Chiu's scoring system and for determination of small intestinal water content and intestinal mucosal lactic acid content.miRNA microarray chip analysis was performed in the intestinal mucosal tissues, and quantitative real-time PCR was used to verify the differentially expressed miRNAs.Another 24 adult male Sprague-Dawley rats, weighing 230-250 g, were randomly divided into 4 groups (n=6 each)using a random number table: miR-378 inhibitor antagomir group(group An), miR-378 agonist agomir group(group Ag), inhibitor control group(group AnC)and agonist control group(group AgC). Antagomir, agomir, antagomir negative control and agomir negative control solutions 100 μl(10 nmol/ml)were injected via the tail vein in An, Ag, AnC and AgC groups, respectively.Intestinal I/R was then produced 24 h later.The intestinal specimens were obtained for microscopic examination of pathological changes which were graded using Chiu's scoring system and for determination of small intestinal water content and intestinal mucosal lactic acid content. Results Compared with group S, Chiu's score, intestinal water content and intestinal mucosal lactic acid content were significantly increased in the other 5 groups.Compared with group I/R, Chiu's score, intestinal water content and intestinal mucosal lactic acid content were were significantly increased in group An, the parameters mentioned above were decreased in group Ag, and no significant change was found in the parameters mentioned above in AnC and AgC groups.The pathological damage was aggravated in group An and was attenuated in group Ag as compared with group I/R.miRNA microarray chip analysis revealed that a total of 19 miRNAs were found to be differentially expressed.Among the 19 differentially expressed miRNAs, the expression of miR-292-3p was significantly up-regulated, and the expression of 18 miRNAs including miR-378 was down-regulated.The expression of 9 miRNAs verified by quantitative real-time PCR was down-regulated, which was consistent with the results of miRNA microarray chip analysis. Conclusion Nineteen miRNA expression changes after I/R, and it is confirmed that down-regulation of miR-378 expression is related to the intestinal I/R injury in rats. Key words: MicroRNAs; Reperfusion injury; Intestine