Effects of spironolactone on aorta remodeling and plasma adrenomedullin levels in hypertensive rats

Objective To investigate the effects of spironolactone on aorta remodeling and the levels of plasma adrenomedullin in hypertensive rats.Methods The models of hypertensive rat were established by using the method of abdominal aortic construction.44 male Wistar rats were randomly divided into 4 groups,model group:hypertensive rats serving as controls,peri group:hypertensive rats subjected to perindopril treatment,2 mg·kg -1·d -1,spi group:hypertensive rats receiving spironolactone treatment,20 mg·kg -1·d -1,sham operation group:sham operative rats serving as controls.Ultrasonic diagnostics was used to detect the thickness and the diastolic and systolic diameter of aorta.The maximal dilatory response to cumulative doses of sodium nitroprusside (SNP;10 -9 to 10 -6 mol/L) was evaluated,and then aorta was detected by morphometry.Plasma adrenomedullin was detected by radioimmunoassay respectively.Results As compared with those in sham operation group,SBP and thickness of aorta in model group were significantly increased (P0.01);the media thickness of aorta,the ratio of media thickness vs diameter of lumen of aorta increased by 19.72%,36.84% respectively (P0.01);all the parameters above in spi group obviously decreased (P0.01);there was no significant difference between spi group and peri group.There was no significant difference in systolic and diastolic diameter of aorta among all the groups (P0.05).The maximal vascular relaxation responses to SNP were alike among four groups (P0.05).As compared with that in sham operation group,plasma ADM in model group was increased significantly (P0.01);both spironolactone and perindopril attenuated the increase of plasma ADM (P0.01).Conclusion Spironolactone could attenuate the increase of SBP,decrease the thickness of aorta,prevent aorta remodeling,its effects is the same as that of perindopril.After treatment of spironolactone and perindopril,plasma ADM decreases companying the decrease of aortic thickness,the action mechanism may be that plasma ADM plays a compensatory role in hypertension by inhibiting RAAS or (and) a direct effect to reverse aorta remodeling.