MicroRNA-21 is upregulated during intestinal barrier dysfunction induced by ischemia reperfusion

This study aimed to investigate the expression of miRNA-21 during intestinal barrier dysfunction induced by intestinal ischemia reperfusion. Forty SPF SD rats were divided into 5 groups randomly. Intestinal ischemia-reperfusion injury (IRI) was induced by mesenteric artery occlusion for 1 h and reperfusion for 1 h, and the rats were sacrificed at 1, 3, 6 and 12 h after reperfusion. Fresh intestine tissues were immediately isolated for the measurement of transepithelial electrical resistance (TER). The levels of cytokines, ICAM-1, DAO, iFABP and MPO in serum were determined by ELISA. Intestinal tight junction proteins occludin and claudin-1 were detected by immunofluorescence analysis and Western blot analysis. miR-21 expression in intestinal tissues was measured by RT-PCR. Compared with sham group, the levels of pro-inflammatory cytokines TNF-α and IL-6 and ICAM-1, DAO, iFABP and MPO increased while IL-10 level decreased in intestinal ischemia-reperfusion group. In addition, the levels of intestinal tight junction proteins occludin and claudin-1 decreased while miR-21 level increased in intestinal ischemia-reperfusion group, compared with sham group. In conclusion, miR-21 expression is upregulated during intestinal barrier dysfunction induced by IRI. miR-21 may play an important role in the regulation of intestinal barrier function. Keywords: Intestinal epithelial barrier, MicroRNA-21, Ischemia-reperfusion injury, Tight junctio