皮质抑素调控钙化相关基因减轻大鼠动脉钙化

Cortistatin inhibits aortic calcification in rats by regulating calcification-related gene expression

目的探讨皮质抑素(cortistatin,CST)对大鼠主动脉钙化的影响及其可能的分子机制。方法利用维生素D3联合尼古丁(VDN)所致的大鼠动脉钙化模型,分别采用孔雀绿直接显色法、邻甲酚酞络合酮比色法和von Kossa染色法测定大鼠血浆磷、钙水平和主动脉组织的钙含量和钙沉积,应用RT-PCR方法检测主动脉组织钙化相关基因mRNA表达。结果与对照组相比较,VDN使大鼠主动脉的钙含量增加70.2%(P<0.05),引起弹力纤维紊乱、中断,von Kossa染色阳性的棕黑色颗粒明显增多。VDN+CST组与单独VDN组相比较,持续皮下泵入CST使主动脉的钙含量减少45.6%(P<0.05),弹力纤维紊乱中断减轻和棕黑色颗粒明显减少。而血钙、磷及钙磷乘积在各组间无显著性差异。RT-PCR结果证实VDN组主动脉组织的BMP-2 mRNA和Pit-1 mRNA表达分别增加53.2%(P<0.05)和34.0%(P<0.01),而MGP mRNA表达减少27.0%(P<0.05)。持续皮下泵入CST使主动脉组织BMP-2mRNA和Pit-1 mRNA表达较单独VDN组分别下降38.3%(P<0.01)和17.4%(P<0.05),而MGP mRNA表达增加34.9%(P<0.01)。主动脉组织OPG mRNA表达在各组间均无显著性差异。结论 CST能够减轻VDN所致的大鼠动脉钙化,可能与其纠正促\抑钙化相关基因表达失衡有关,从而为CST防治动脉钙化提供实验依据。

AIM To investigate the effect and the molecular mechanism of cortistatin （CST） on rat aortic calcification. METHODS In vivo rat model of arterial calcification induced with vitamin D3 and nicotine （VDN）, plasma calcium and calcium content of aortic tissue were determined by o-cresolphthalein complexion colorimetric method and von Kossa staining, respectively. Plasma phosphorus was measured by malachite green colorimetric method and calcification-related gene expression in aortic tissues was detected by RT-PCR. RESULTS Compared with those in the control group, VDN increased calcium content by 70.2% （P〈0.05）. Disorganized and broken elastic fibers were seen and von Kossa staining showed more positive brown/black particles in rat aortic tissues in VDN group. After chronic administration of CST 25 μg/kg, aortic calcium content was reduced by 45.6% （P〈0.05） and disorganized elastic fibers and brown/black particles decreased in the VDN＋CST group. No significant difference was observed in plasma calcium, phosphorus and calcium-phosphorus product between groups. Compared with those in the control group, expression of BMP-2 mRNA and Pit-1 mRNA increased by 53.2% （P〈0.05） and 34.0% （P〈0.01）, respectively, and MGP mRNA expression decreased by 27.0% （P〈0.05） in rat aortas in VDN group. After CST treatment, BMP-2 mRNA and Pit-1 mRNA expression were down-regulated by 38.3% （P〈0.01） and 17.4% （P〈0.05）, respectively, and MGP mRNA expression increased by 34.9% （P〈0.01） in aortic tissues of VDN＋CST group compared with those in the VDN group. The amount of BMP-2 mRNA, Pit-1 mRNA and MGP mRNA expression showed no significant differences between control group and VDN＋CST group. There was no significant difference in OPG mRNA expression of aortic tissue between groups. CONCLUSION CST alleviates rat arterial calcification induced by vitamin D3 and nicotine. Anticalcification of CST may be mediated by maintaining the expression homeostasis of calcification-related genes. These findings may provide some experimental evidence of using CST for the prevention and treatment of arterial calcification.