The after-effect of short-term use of losartan on blood pressure and myocardium in prehypertension rats / 重庆医学

ABSTRACT

Objective To observe the influence of losartan on rats′blood pressure and myocardium.Methods To randomly divide 24 4-year-old spontaneously hypertensive male rats into 3 groups.Group A is given normal saline(NS);group B is given losartan 20 mg/kg in 4-week-old;group C is given the same dose in 1 2-week-old;To take another 4-week-old male wistar rats to form group D,feed NS served as normal comparison.Each group was given NS or losartan one time each day through intragastric administration for 4 weeks.Follow up 24 weeks after stopping the medicine.Rats’SBP were measured through tail cuff method respectively when at 4,8,12,16,20 and 24 weeks’ time.After 24 weeks,cut off the head to take the sample,the RVW/BW,HW/BW,LVW/BW were measured through weighing method.To observe the morphologic change of the cardiac muscles and measure the area of myocardium cell cross section through HE stain method.Ra-dioimmunoassay was used to measure the AngⅡand Aldo level of the blood plasma and myocardium.Results At the age of eight-week,the SBP of group A and C are higher than those of group D(P0.05).About LVW/BW,HW/BW and the ar-ea of myocardium cell cross section,group A increased significantly in comparison with group D (P<0.05),group B and C decreased in comparison with group A(P<0.05),group B decreased significantly in comparison with group C(P<0.05).Through the observation of the area of myocardial cell cross section under the microscopy,group A increased significantly in comparison with group D about myocardial cell fattened and the gap between cells are widened,the fibers of mesenchyma proliferates.group B and D are similar,group C is between group B and A.The level of AngⅡand Aldo in plasma and myocardium of group A increased significantly in comparison with group D (P<0.05),group B decreased significantly in comparison with group A and C(P<0.05).Conclusion To use losartan for a short time in trea-ting rats with prehypertension can get the after-effect of reducing blood pressure and anti-ventricular-remodeling.