Title: Effects and Mechanisms of Losartan on the Structure of Resistant Vessel in Spontaneously Hypertensive Rat
Abstract: Objective To evaluate the effects of Losartan on systolic blood pressure,the structure of resistant vessel and the changes of plasma angiotensinⅡ in spontaneously hypertensive rats (SHR). Methods six weeks male SHR and WKY were divided into three groups at random: SHR losartan group、SHR control group、WKY normal control group. Losartan 30 mg·kg 1 ·d 1 was administered by gavage to rats in SHR Losartan group. After 17 weeks treatment, Wall to lumen area ratios (W/L)of mesenteric arteries (3 rd grade branch ) were calculated by computer image analysis system. Systolic blood pressure(SBP) were measured. The level of vessel hypertrophy was assessed by means of transmission electron microscope. The plasma renin activity and AngⅡlevel was determined by RIA method. Results (1) After 17 weeks treatment, the blood pressure of SHR losartan group was decreased compared with SHR control group ( P 0 05). (2) The W/L in SHR losartan group was significantly decreased compared with SHR control group ( P 0 01). There was no remarkable difference in W/L between SHR losartan and WKY group( P 0 05).While the W/L in SHR losartan group is still remain in a higher level than that of WKY rats( P 0 05). The ultrastructures of mesenteric arteries in SHR losartan group were similar with those of WKY normal group; however, ultrastructure change in mesenteric arteries in SHR control group were pronouncedly. (3) The plasma renin activities had no significant differences ( P 0 05) between WKY normal group and SHR control group. The plasma renin activities in SHR losartan group increased compared with SHR control group ( P 0 05). AngⅡ level in SHR losartan group significantly increased compared with SHR control group ( P 0 01). The AngⅡ level in SHR losartan group was higher than that in WKY normal group ( P 0 05). Conclusion These results indicated that long term treatment with Losartan effectively reduced blood pressure、attenuated and regressed the resistant vessel hypertrophy during the development of hypertension in SHR.
Publication Year: 2001
Publication Date: 2001-01-01
Language: en
Type: article
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