中文摘要：

目的：在离体钙化的血管平滑肌细胞上，观察内皮素受体阻断剂对血管平滑肌细胞（VSMCs）钙化的影响，探讨内皮素（ET）促进细胞钙化的信号转导和分子机制。方法：β-磷酸甘油制备钙化VSMCs；通过细胞钙含量，[^45Ca^2＋]摄取，碱性磷酸酶活性测定，判断钙化程度，[^3H]-胸腺嘧啶（[^3H]-TdR）和[^3H]-亮氨酸（[^3H]-Leu）掺入测定细胞DNA合成，竞争性定量RT—PCR测定VSMCs骨桥蛋白（OPN）mRNA水平，放射免疫法测定培养上清ET含量。结果：与正常对照VSMCs相比，钙化VSMCs内钙含量，[^45Ca^2＋]摄入及碱性磷酸酶活性分别增加119％、174％和7倍（P〈0．01），OPN表达增加86％；细胞生长活跃，[^3H]-TdR和[^3H]-Leu分别增加71％和35％；钙化细胞培养基中内皮素含量较对照组增加35％（P〈0．05）。而钙化加内皮素受体阻断剂BQ123组明显减轻VSMCs钙化程度，钙含量，[^45Ca^2＋]摄入及碱性磷酸酶活性分别较钙化组降低33％、37％、40％（均P〈0．01），OPN表达明显下调25％；细胞增殖活性明显降低。结论：BQ123可减轻VSMCs钙化程度，表明ET促进VSMCs钙化主要是通过内皮素A型受体（ET—A）途经。

英文摘要：

AIM： To observe the effect of endothelin receptor antagonist （BQ123） on calcification in rat vascular smooth muscle cells （VSMCs） in vitro. METHODS： Calcification of cultured rat VSMCs was produced by incubation with β - glycerophosphate. Calcium content, Ca^2＋ deposition and alkaline phosphatase activity were analyzed to estimate the extent of calcification. The DNA synthesis was detected by [^3H ] - TdR and [^3H ] - Leu incorporation. Osteopontin （OPN） mRNA was measured by competitive quantitative RT -PCR. Content of ET was measured by radioimmunoassay （RIA）. RESULTS： The results showed that compared with the control, the content of calcium, [^45 Ca^2＋ ] uptake and alkaline phosphatases activities in calcified VSMCs increased by 118% , 174% and 7 - fold （ all P 〈 0. 01 ） , respectively. The expression of OPN mRNA in calcified VSMCs was up - regulated by 86% （ P 〈 0.01 ）. The calcified VSMCs grew rapidly, in which [^3H] - TdR and [^3H] - Leu were elevated by 71% and 35%. The content of ET in calcified VSMCs medium was increased by 35% as compared with control. Furthermore, calcified VSMCs plus BQ123 groups obviously relieved degree of calcification, of which calcium content, Ca^2＋ deposition and alkaline phosphatase activities were 33% , 37% , 40% lower than those in calcified VSMCs （ P 〈 0. 01 ） , respectively. The expression of OPN mRNA was downregulated by 25% （P 〈 0. 01 ） and significantly inhibited VSMCs proliferation. CONCLUSION： BQ123 reduces VSMCs calcification, suggesting that ET promotes calcification in VSMCs mainly by ET/ ETA receptor pathway.