Changes of miR-155 in lung tissue of bronchial asthma mice and its effect on COX-2

Objective To investigate the changes of microRNA-155 (miR-155) and its effect on cyclo-oxygen-ase-2 (COX-2) in lung tissue of bronchial asthma (asthma) mice. Methods Twenty-eight female BALB/c mice were randomly divided into four groups (n=7 each): control group, asthma group, antagomir negative control group and antagomir intervention group.The asthma model was induced by intraperitoneal injection of chicken egg ovalbumin (OVA) and repeated ultrasonic atomization inhalation, and observed the asthma performance of each group of mice.Hematoxylin-eosin staining was used to observe the morphological changes of lung tissue, enzyme linked immunosorbent assay kit was used to measure the concentration of prostaglandin E2 (PGE2) in peripheral serum, and Western-blotting was used to detect the expression of COX-2 protein, reverse transcription PCR was used to detecte the expression of COX-2 mRNA and miR-155-5p. Results The expressions of miR-155-5p, COX-2 and PGE2 in the asthma group was significantly higher than those in the control group (t=-21.420, -15.270, -9.613, all P<0.01). The antagomir intervention group miR-155, COX-2, and PGE2 were significantly lower than the asthma group (t=-15.273, -12.421, -6.025, all P<0.01). The expression of miR-155-5p was significantly positively correlated with COX-2 in the lung (r=0.977, P<0.01). Conclusions The expression of miR-155-5p is increased in lung tissue of asthma mice, miR-155-5p may be involved in the pathogenesis of asthma by regulating the COX-2/PGE2 pathway.