Effect of PASMC apoptosis on reversal of hypoxic pulmonary arterial remodeling during reoxygenation and its related molecular mechanism / 中国病理生理杂志

ABSTRACT

AIM: To explore the effect of pulmonary arterial smooth muscle cell (PASMC) apoptosis on the reversal of hypoxic pulmonary arterial remodeling during reoxygenation and its possible mechanism.METHODS: Male SD rats (n=24) were randomly divided into normoxia for 4 weeks group, hypoxia for 4 weeks group, reoxygenation for 1 week after hypoxia for 4 weeks group and reoxygenation for 6 weeks after hypoxia for 4 weeks group.Right ventricular systolic pressure (RVSP), right ventricular hypertrophy index, pulmonary arterial medial thickness (MT) and medial area (MA) as well as autophagy and apoptosis in the pulmonary arterial medial layer were examined during hypoxia-reoxygenation.The rat primary PASMCs were divided into normoxia for 48 h group, hypoxia for 48 h group, reoxygenation for 24 h after hypoxia for 48 h group and normoxia for 72 h group to explore the changes of PASMC autophagy and apoptosis following hypoxia-reoxygenation.Finally, primary PASMCs were divided into normoxia for 72 h group, reoxygenation for 24 h after hypoxia for 48 h group and reoxygenation for 24 h after hypoxia for 48 h + chloroquine (inhibitor of autophagy) group to investigate the effect of PASMC autophagy during hypoxia on the apoptosis during reoxygenation.RESULTS: After hypoxia for 4 weeks, the RVSP, during right ventricular hypertrophy index, MT and MA increased significantly compared with normoxia group (P<0.05), and gradually decreased during reoxygenation.The expression of LC3 in the pulmonary arterial medial layer increased evidently after hypoxia and gradually reversed during reoxygenation.Moreover, the P62 and cleaved caspase-3 expression decreased after hypoxia compared with normoxia group, and increased markedly following reoxyge-nation.The expression of cleaved caspase-3/PARP in rat primary PASMCs decreased significantly under hypoxia (P<0.05), and increased evidently during reoxygenation.The expression of P62 and LC3-II decreased markedly under hypoxia (P<0.05).After inhibition of PASMC autophagy under hypoxia, the expression of cleaved caspase-3/PARP decreased remarkably during reoxygenation (P<0.05).CONCLUSION: The PASMC apoptosis participates in the reversal of hypoxic pulmonary arterial remodeling, and the PASMC autophagy under hypoxia might facilitate its apoptosis during reoxygenation.