目的探讨高钙血症对血管钙化的影响。方法用维生素D3加尼古丁诱导大鼠血管钙化模型,von Kos-sa染色、钙含量测定、^45Ca^2+聚集及碱性磷酸酶活性测定判断钙化程度,用竞争性半定量逆转录聚合酶链反应方法测定血管钙化标志分子骨桥蛋白和pactin mRNA水平。结果钙化组大鼠血压升高,收缩压较对照组高28%(P〈0.05);血管von Kossa染色见血管中膜弹性纤维间可见大量棕黑色颗粒沉积。主动脉钙含量、^45Ca^2+沉积及碱性磷酸酶活性分别较对照高3.7倍、1.3倍和1.4倍(P〈0.01)。钙化血管组织骨桥蛋白mRNA表达上调46%(P〈0.01)。与对照组比较,高钙摄入增加血钙而降低血磷水平(2.49±0.14比2.20±0.12;1.25±0.05比1.40±0.07,P〈0.01),单纯高钙摄入组主动脉钙含量、^45Ca^2+沉积及碱性磷酸酶活性与对照组比较差异无显著性(P〉0.05)。而诱导钙化后给予高钙饮食可增加血管钙化程度,与单纯钙化组比较,主动脉钙含量、^45Ca^2+沉积及碱性磷酸酶活性分别升高了12%(P〉0.05)、38%(P〈0.01)和15%(P〈0.01);骨桥蛋白表达上调34%(P〈0.01)。结论高钙摄入可以加重大鼠血管钙化。
Aim To study the effects of hypercalcinemia on vascular calcification of rat. fication of Sprague-Dawley rats was induced by vitamin D3 plus nicotine (VDN). Calcification was confirmed by von Kossa staining, measurerment of calcium content, ^45Ca^2+ accumulation and alkaline phosphatase (ALP) activity of intracellular and vascular tissue. Semi-quantitative-reverse transcription polymerase chain reaction(RT-PCR) was used to determine osteopontin (OPN, a marker of calcification) and β-actin mRNA level. Results The results showed that VDN treated rat showed a higher systolic pressure by 28 % (P〈0.05) than that in control rat. Von Kossa staining for calcification, showed strong positive staining as black/brown areas among the elastic fibers of the medial layer in calcified aorta. The aortic calcium content, ^45Ca^2+ accumulation and ALP activity in calcified arteries were increased by 3.7-fold, 1.3-fold and 1.4-fold respectively ( P 〈 0. 01 ), compared with control. The amotmt of OPN mRNA in calcified aorta was elevated by 46% (P〈0.01) compared with that of control. High dose calcium uptake increased plasma calcium content and decreased phosphate level (2.49±0.14 vs 2.20±0. 12 and 1.25±0.05; 1.40±0.07, P〈0.01) compared with control . There are no significant changes in aortic calcium content, ^45 Ca^2+ accumulation and ALP activity in high dose calcium treatment alone. However, high dose calcium can aggravate vascular calcification ot rat treated with VDN. The aortic calcium content, ^45Ca^2+ accumulation, ALP activity and OPN mRNA level were increased by 12% (P〉0.05), 38% (P〈0.01), 15%(P〈0.01), and 34% (P〈0.01 ), respectively, in rat treated with VDN and high dose calcium, compared with that in rat treated with VDN alone. Conclusions High dose calcium uptake can aggravate vascular calcification of rat.