自发性高血压大鼠血浆一氧化氮水平的变化

背景有关高血压与一氧化氮关系的研究主要为单一时间的对照研究,但随着血压的改变一氧化氮如何变化的研究较少.目的观察自发性高血压大鼠(spontaneoulyhypertensive rats,SHR)血浆一氧化氮浓度的变化,探讨一氧化氮与高血压发生发展的关系,为判断高血压的预后提供理论依据.设计非随机对照的实验研究.地点、材料和干预实验在广州暨南大学完成.选择SHR30只,雌性6只,雄性9只(高血压组);大鼠WKY 30只,雌性7只,雄性8只(对照组).分别饲养3,6和12个月,测定血压,用硝酸银还原法测定两组大鼠血浆中一氧化氮的含量.主要观察指标观察随着高血压的不断发展,自发性高血压大鼠血浆一氧化氮浓度的变化.结果①血压变化各时期对照组大鼠血压差异无显著性意义,介于(135.0±9.8)～(147.8±11.3)mmHg;高血压组大鼠血压随着月龄增加逐渐升高,12个月达(197.3±7.5)mmHg,各时间点均明显高于对照组大鼠(t=4.132～7.921,P＜0.01).②血浆一氧化氮浓度的变化对照组大鼠血浆一氧化氮浓度各时间点差异无显著性意义(P＞0.05),维持在(11.5±3.9)～(14.4±3.4)μmol/L水平;高血压组大鼠血浆一氧化氮浓度在3,6个月分别为(16.6±4.5)和(18.5±4.2)μmol/L,明显高于对照组大鼠,但在12个月却明显较对照组大鼠低[(9.3±3.6)μmol/L](t=3.890,P＜0.01),同组内与3,6个月比较亦显著减少(t=3.890,P＜0.01).结论在高血压发生和发展过程中血浆一氧化氮存在反应性升高的变化,而在高血压的后期,一氧化氮的合成明显不足,这种变化可能与高血压的预后有关.

Changes of plasma nitric oxide level in spontaneously hypertensive rats

BACKGROUND: Most controlled studies on the relationship between hypertension and nitric oxide(NO) examine only the changes of NO at a certain time point, whereas NO changes in relation to the variation of the blood pressure in the development of hypertension are scarcely addressed in randomized studies.OBJECTIVE: To study the changes of plasma NO concentration in spontaneously hypertensive rats(SHR) to understand the relationship between NO and hypertension.DESIGN: Nonrandomized, matched control experiment.SETTING, PARTICIPANTS and INTERVENTION: The experiment was completed in Jinan University. After fed for 3, 6 and 12 months respectively, 15 SHRs(6 females, 9 males) and 15 Wistar-Kyoto(WKY) rats(7 females, 8males) were sacrificed to measure the blood pressure and determined plasma NO levels with the silver nitrate deoxidize method.MAIN OUTCOME MEASURES: The change of plasma NO concentration in SHRs with the development of hypertension was observed.RESULTS: The blood pressure of WKY rats varied insignificantly between (135.0 ±9.8) and(147.8 ± 11.3) mmHg in the course of 1-year observation, but in SHRs, significantly elevated blood pressure was observed in comparison with the WKY rats( t =4. 132-7.921, P ＜ 0.01), reaching the height of(197.3 ±7. 5) mmHg in the 12th month. Plasma NO concentration of WKY rats underwent slight variation between(11. 5 ±3. 9) and(14. 4 ±3.4)μmol/L, but was significantly increased in SHRs at the 3rd and 6th months [(16. 6 ±4. 5) μ mol/L and(18. 5 ±4. 2) μ mol/L] then lowered to(9.3 ±3.6) μ mol/L, which was below the level in WKY rats at the 12th months( t =3.890, P ＜ 0. 01) and those at the 3rd and 6th months in SHRs( t = 3. 890, P ＜0.01 ). There was a positive correlation between plasma NO concentration and the blood pressure at 3 and 6 months, but an inverse one in the 12th month.CONCLUSION: Plasma NO concentration is elevated in response to the onset and progression of hypertension, but in advanced stage of hypertension,NO synthesis is apparently insufficient, which may be indicative of the prognosis of hypertension.