Regulatory effect of adrenomedulin on pulmonary tissue oxidative stress in rats with pulmonary hypertension induced by high pulmonary blood flow / 中国病理生理杂志

ABSTRACT

AIM: To explore the regulatory effect of adrenomedullin (ADM) on pulmonary oxidative stress in the rats with pulmonary hypertension induced by high blood flow.METHODS: Healthy male SD rats (n=22) were randomly divided into control group, shunt group and shunt with ADM group.Abdominal aorta and inferior vena cava shunting was produced in the rats in shunt group and shunt with ADM group.After 8 weeks, ADM (1.5 μg·kg-1·h-1) was administered into the rats in shunt with ADM group subcutaneously by mini-osmotic pump for 2 weeks.Mean pulmonary artery pressure (mPAP) was evaluated by a right cardiac catheterization procedure.The ratio of right ventricular mass to left ventricular plus interventricular septal mass [RV/(LV+SP)] and relative medial thickness (RMT) in pulmonary muscularized arteries were calculated.The content of malonaldehyde (MDA), total antioxidative capacity (T-AOC), and activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in lung tissues were detected by colorimetry.The expression of NADPH oxidase 4 (NOX4) in the lung tissue was analyzed by Western blot.RESULTS: Compared with control group, the mPAP, RV/(LV+SP) and RMT in pulmonary muscularized arteries in shunt group were all significantly increased.The content of MDA and the expression of NOX4 in the lung tissues were significantly increased.The T-AOC, and activity of SOD and GSH-Px in the lung tissues were significantly decreased.However, mPAP, RV/(LV+SP) and RMT in pulmonary muscularized arteries in shunt with ADM group were significantly decreased as compared with shunt group.Meanwhile, ADM decreased the content of MDA and the expression of NOX4 in the lung tissues, but increased the T-AOC, and activity of SOD and GSH-Px in the lung tissue of shunt rats.CONCLUSION: ADM inhibits oxidative stress response in the development of pulmonary hypertension and pulmonary vascular structural remodeling induced by high pulmonary blood flow in the rats by down-regulating the NOX4 expression and strengthening the anti-oxidation response.