膳食钙对高血压大鼠血压的影响及其机理研究

EFFECTS OF DIETARY CALCIUM ON BLOOD PRESSURE AND PROPOSED MECHANISM IN HYPERTENSIVE RATS

方法：雄性ＳＤ大鼠经外科摘除左肾，按血压并参考体重随机分为三组：Ａ、Ｂ组饲料含钙（Ｃａ）０．７８％，Ｃ组含Ｃａ２．０％，Ｂ、Ｃ组每周皮下注射去氧皮质酮（ＤＯＣ）２５ｍｇ／ｋｇｂｗ，实验共持续７周。结果：Ｂ组血压从第４周开始显著高于Ａ、Ｂ组：Ｂ、Ｃ组血清亚硝酸根离子（ＮＯ－２）的浓度均显著高于Ａ组（Ｐ＜０．０１），Ｃ组亦显著高于Ｂ组（Ｐ＜０．０１）。依赖还原性辅酶Ⅱ－黄递酶（ＮＡＤＰＨ－ｄ）组织化学染色显示；Ｂ、Ｃ组主动脉内膜一氧化氮合成酶（ＮＯＳ）阳性反应较Ａ组增强，且中膜亦呈阳性反应；Ｃ组较Ｂ组阳性反应增强，其中膜亦呈阳性反应。

All rats were uninephrectomized and divided into three groups:in group A and B,the fodder contained 0.78% of calcium,and 2.0% in group C.Group B and C received deoxycorticosterone (DOC) (25mg/kg body weight,s.c.)once a week.The study lasted seven weeks.The results showed that blood pressure of group B was higher than the other two groups from the fourth week and lasted to the seventh week.The serum concentrations of NO - 2 in group B and C were higher than that of group A; and the plasma concentrations of group C were higher than that of group B.NADPH diaphorase histochemical staining method was used to investigate the distribution and expression of nitric oxide synthase(NOS) in aortic wall.As compared with group A,positive reactivity of NOS in group B and C not only exsited in aortic intima,but also in aortic media.Moreover,the positive reactivity of NOS in aortic intima of group B and C was stronger than that in group A;and intensive positive reactivity of NOS was shown in aortic media of group C.These data suggest that nitric oxide(NO) may play an important role in the effects of higher dietary calcium on blood pressure in DOC NaCl hypertensive rats.