Effect of adrenomedullin on intestinal epithelial barrier function under hypoxia/reoxygenation injury and possi-ble mechanism / 局解手术学杂志

ABSTRACT

Objective To investigate the effect of adrenomedullin on epithelial barrier function of Caco-2 cells under hypoxia/reoxygen-ation injury and the molecular mechanism.Methods Build hypoxia/reoxygenation injury model,Caco-2 cells were randomly divided into three groupsnormal control group( N) ,hypoxia/reoxygenation group( H/R) and hypoxia/reoxygenation plus 1 μmol/L adrenomedullin group(H/R+AM).Transepithelial electrical resistance(TEER) was determined,and the laser confocal microscope was used to detect the construction of tight junction.The protein expressions of tight junction proteins (Occludin and ZO-1) and nuclear factor kappa B(NF-κBp65) were examined by using western blotting.Results Pretreatment of AM significantly attenuated the disruption of morphological structure of tight junction caused by H/R.The TEER of N group,H/R group and H/R+AM group were(157.68 ±5.54),(96.06 ±3.42),(134.56 ± 4.72) Ohm/cm2 respectively.After AM pretreatment, the TEER were significantly raised compared with that in H/R group by 40.00%(P<0.05).The relative protein expressions of Occludin and ZO-1 in N group,H/R group and H/R+AM group were [(0.43 ±0.03), (0.27 ±0.04)],[(0.20 ±0.03),(0.15 ±0.07)],[(0.32 ±0.15),(0.21 ±0.03)]respectively.After AM pretreatment,the protein ex-pression of Occludin and ZO-1 were significantly raised compared with that in H/R group(by 60.00% and 40.00%).Simultaneously,the relative protein expressions of NF-κBp65 in N group,H/R group and H/R+AM group were (0.53 ±0.30),(2.89 ±0.16),(1.75 ±0.25) respectively.And H/R induced NF-κBp65 activation was significantly inhibited by AM treatment (decreased as compared with H/R group by 40.00%).Conclusion AM can attenuate intestinal epithelial barrier dysfunction by regulating the expression of intestinal tight junction pro-teins.The inhibition of NF-κB activation may be involved in this mechanism.