长期规律维生素D干预对自发性高血压大鼠肾素及其受体的影响

Influence of long-term regular vitamin D intervention on renin and renin receptor in spontaneously hypertensive rats

目的探讨维生素D长期规律用药对自发性高血压大鼠肾素及肾素受体的影响。方法自发性高血压大鼠20只随机分成两组(n=10),实验组给予维生素D33μg/kg溶于0.5mL丙二醇中腹腔注射,每周两次,总计12周;对照组以等容积的丙二醇腹腔注射。每周以无创测压法监测大鼠血压变化。干预前后收集血清和尿液检测25-羟基维生素D3[25-(OH)D3]、钙、肾素和24h尿白蛋白的浓度;RT-PCR法检测实验组和对照组肾脏维生素D受体(VDR)、肾素及肾素受体mRNA的表达水平;免疫组化观察肾脏和心脏肾素受体的分布部位及分布强度;HE染色观察大鼠病理改变。结果与对照组相比,实验组收缩压降低[(156±9)比(170±8)mm Hg,P<0.05];血25(OH)D3和钙浓度升高[分别(117.5±13.7)比(68.2±12.2)μg/L,(2.34±0.10)比(2.15±0.16)mmol/L,P<0.05],肾素[(232.7±18.8)比(263.2±32.8)ng/L,P<0.05]和24h尿蛋白[(0.50±0.36)比(0.83±0.44)mg,P<0.05]水平减低。RT-PCR结果显示,实验组大鼠肾脏中VDR mRNA的表达量高于对照组[(0.595±0.053)比(0.461±0.048),P<0.05];肾素mRNA表达水平低于对照组[(0.133±0.007)比(0.316±0.012),P<0.05];两组间肾素受体mRNA表达差异无统计学意义(P>0.05)。免疫组化结果显示,肾素受体在心、肾和血管等分布广泛,肾素受体累积光密度值在两组表达差异无统计学意义(P>0.05)。HE染色显示,实验组高血压病理改变明显轻于对照组。结论维生素D能够抑制高血压大鼠肾素基因的表达,减轻高血压肾损害,但对肾素受体的调节作用不明显。

Objective To explore the influence of long-term regular vitamin D intervention on renin and renin receptor in spontaneously hypertensive rats. Methods A total of 20 spontaneously hypertensive rats were randomly divided into two groups （n= 10）. The experimental group received 3 μg/kg vitamin D3 dissolved in 0.5 mL propylene glycol by intraperitoneal injection （twice a week） for 12 weeks, and the control group was given equal volume of propylene glycol alone. Blood pressure was measured every week. The level of serum 25-hydroxy vitamin Da [25-（OH）D3 ], calcium, renin and 24 hours urinary albumin were determined. The mRNA expression of vitamin D receptor（VDR）, renin and renin receptor in kidney of the two groups were detected by RT-PCR. Distribution of renin receptor and pathological changes in kidney and heart were examined by immunohistochemical and HE staining. Results Compared with those of control group, the systolic blood pressure [（156±9） vs （170±8）mm Hg, P〈 0.05], serum renin [（232. 7±18. 8） vs （263.2±32.8）ng/L, P〈0.05] and 24 hours urinary albumin [（0.50±0.36） vs （0.83±0.44} mg, P〈0.05] of experimental group were lower, while the serum concentration of 25-（OH）D3 and calcium in experimental group were higher [（117.5±3.7） vs （68.2±12.2）μg/L, （2.34±0.10） vs （2.15±0. 16）mmol/L, all P〈0.05]. After the treatment with vitamin D, the VDR mRNA expression was significantly increased [（0. 595±0. 053） vs （0. 461±0. 048）, P〈0.05], but the renin mRNA expression in kidney was markedly decreased [（0. 1334±0. 007） vs （0. 3164±0. 012）, P〈0.05]. Renin receptor was widely distributed in heart, vessels and kidney, but there was no statistic significant difference of the receptor expression between the two groups （P〉 05]. HE staining showed that hypertensive pathological changes in control group was more obvious than that in experimental group. Conclusion Treatmemt with vitamin D could inhibit renin expression and attenuate the damage of kidney in spontaneously hypertensive rats, but exert no effects on renin receptor expression in the kidney.