摘要
目的通过研究丹参酮ⅡA对压力超负荷大鼠肥厚心肌一氧化氮(NO)及内皮型一氧化氮合酶(eNOS)基因表达和细胞内游离钙离子浓度([Ca2+]i)的影响,探讨丹参酮ⅡA抑制高血压左心室肥厚的分子生物学机制。方法SD大鼠行腹主动脉缩窄术建立压力超负荷左室心肌肥厚模型,术后4周将手术大鼠随机分为手术对照组(B组)、丹参酮低剂量组[C组,10mg/(kg·d),腹腔注射]、丹参酮高剂量组[D组,20mg/(kg·d),腹腔注射]及缬沙坦组[E组,10mg/(kg·d),灌胃],另有8只SD大鼠作为假手术组(A组)。用药8周后检测各组尾动脉压,取左心室组织检测左心室质量指数(LVMI),采用苏木精-伊红染色法测量心肌纤维直径(MFD),硝酸还原法测定心肌组织NO的含量,逆转录-聚合酶链式反应(RT-PCR)、免疫印迹法(Western blot)分别检测eNOS的mRNA和蛋白表达水平,利用激光共聚焦显微镜测定心肌细胞[Ca2+]i浓度的变化。结果①B、C、D组的血压显著高于A、E组(均P<0.01),C、D组与B组间血压的差异无显著性意义(均P>0.05)。②C、D、E组LVMI、MFD均高于A组(均P<0.05),显著低于B组(均P<0.01)。③C、D、E组的NO含量明显高于B组(均P<0.01),但仍低于A组(均P<0.05)。④B组eNOS蛋白和mRNA表达水平明显低于其他各组(均P<0.01);E组eNOS蛋白和mRNA表达水平显著低于A、C、D组(均P<0.05);C、D组eNOS蛋白和mRNA表达水平与A组比较,差异无显著性意义(均P>0.05)。⑤B组细胞内[Ca2+]i明显高于其他各组(均P<0.01);E组和C组[Ca2+]i仍高于A、D组(均P<0.05);D组[Ca2+]i与A组比较,差异无显著性意义(P>0.05)。结论丹参酮ⅡA对心肌肥厚的抑制作用是非血压依从性的,丹参酮ⅡA通过降低心肌细胞[Ca2+]i浓度,促进心肌局部NO的产生及eNOS基因表达,起到对高血压心肌肥厚的防治作用。
Objective To observe the effect of tanshinone Ⅱ A on nitrogen monoxidum （NO） content, intracellular Ca^2＋ （[-Ca^2＋ ]i） level and the expression of endothelial nitric oxide synthase （eNOS） in hypertrophic cadiocytes of pressure-overloaded rats and to further explore the molecular biological mechanism by which tanshinone Ⅱ A reverses left ventricular hypertrophy in hypertension. Methods Pressure overload-induced myocardial hypertrophy model was established by abdominal aorta constriction in SD rats, Four weeks after surgical intervention, the rats were divided into myocardial hypertrophy group （group B）, low dose tanshinone Ⅱ A group [-10 mg/（kg · day）, ip, group C], high dose tanshinone Ⅱ A group [-20 mg/（kg · day）, ip, group D] and Valsartan group [-10 mg/（kg · day）, ig, group E] randomly, Another 8 rats （group A） underwent sham operation. Eight weeks later, caudal arterial pressure was detected and the left ventricular mass index （LVMI） was measured. HE staining was used for the measurement of myocardial fiber dimension （MFD）, The content of NO was determined by using Griess method. RT-PCR and Western blot were employed for the detection of the expression of eNOS mRNA and protein respectively. [Ca^2＋ ]i in single cardiac myocyte was assayed by laser-scanning confocal microscope. Results （1） Blood pressure in groups B, C and D was higher than that in groups A and E （P〈0.01） ; There was no significant difference between groups C, D and group B; （2） LVMI and MFD in groups C, D and E were increased as compared with those in group A, but significantly lower than that in group B （P〈0. 01）, （3） The NO content in groups C, D and E was higher than that in group B （P〈0. 01）, but lower than that in group A （P〈0.05） ; （4） The expression of eNOS mRNA and protein in group B was decreased as compared with that in other groups （P〈0. 05）. No significant difference was found in the expression of eNOS mRNA and protein between groups C,D and group A （P〉0.05） ; （5） The [Ca^2＋ ]i level was substantially up-regulated in group B, but accordingly down-regulated in groups C, D and E （P〈0.05）. Conclusion The inhibitory effect of tanshinone HA on myocardial hypertrophy was not blood pressure-dependent. Tanshinone IIA reversed myocardial hypertrophy by blocking the inflow of calcium ion in cadiocytes and promoting the expression of eNOS mRNA in local myocardium and the production of endogenous NO.
出处
《华中科技大学学报（医学版）》
CAS
CSCD
北大核心
2008年第3期286-289,共4页
Acta Medicinae Universitatis Scientiae et Technologiae Huazhong
基金
国家自然科学基金资助项目(No30500657)
