枸橼酸镁激活钙敏感受体抑制高磷诱导的血管平滑肌细胞钙化

Magnesium citrate inhibits hyperphosphorus-induced VSMCs calcification through activating calcium-sensitive receptor

目的探讨枸橼酸镁(magnesium citrate,MgCit)抑制高磷诱导的血管平滑肌细胞(vascular smooth muscle cells,VSMCs)钙化的作用及其机制。方法VSMCs分为正常对照组、高磷组、低剂量MgCit组、高剂量MgCit组和高剂量MgCit+NPS2143(钙敏感受体抑制剂)组;茜素红染色半定量分析VSMCs钙化情况并利用试剂盒检测VSMCs内的钙含量;检测各组细胞成骨样转分化指标,包括碱性磷酸酶(alkaline phosphatase,ALP)活性,以及平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)、平滑肌22α(smooth muscle 22α,SM22α)、核心转录因子(runt-related transcription factor 2,RUNX2)和骨形态蛋白2(bone morphogenetic protein 2,BMP2)的mRNA和蛋白表达水平。结果与对照组相比,高磷组VSMCs的钙含量增加,ALP活性、RUNX2和BMP2的mRNA和蛋白表达增加,SM22α的mRNA表达降低(P<0.05);MgCit能降低高磷诱导的VSMCs的钙化,同时降低ALP活性,降低RUNX2和BMP2的mRNA和蛋白表达,增加SM22α的mRNA表达(P<0.05);当同时给予NPS2143时,MgCit的以上作用被削弱(P<0.05)。结论MgCit能降低高磷诱导的VSMCs的钙化和成骨样转分化程度,该作用与MgCit激活钙敏感受体(CaSR)有关。

Objective To investigate the inhibitory effect of magnesium citrate(MgCit)on hyperphosphorus-induced VSMCs calcification and its mechanisms.Methods VSMCs were divided into the following groups:normal control group,high-phosphorus group,low-dose MgCit group,high-dose MgCit group and high-dose MgCit+NPS2143(calcium-sensitive receptor inhibitor)group.Alizarin red staining was used for semi-quantitative analysis of VSMCs calcification and the calcium content in VSMCs was detected by the commercial kit.The osteogenic transdifferentiation parameters including alkaline phosphatase(ALP)activity,as well as mRNA and protein levels of smooth muscle 22α(SM22α),runt-related transcription factor 2(RUNX2)and bone morphogenetic protein 2(BMP2),were detected in each group.Results Compared with those in the control group,the calcium content of VSMCs in the model group was increased,ALP activity,and the mRNA and protein expressions of RUNX2 and BMP2 were increased,and the mRNA expression of SM22αwas decreased(P<0.05).MgCit could reduce VSMCs calcification,decrease ALP activity,decrease mRNA and protein levels of RUNX2 and BMP2,and increase mRNA levels of SM22αinduced by high-phosphorous(P<0.05).The above effects of MgCit were reduced when NPS2143 was administered simultaneously(P<0.05).Conclusion MgCit can reduce VSMCs calcification and osteogenic transdifferentiation induced by high phosphorus through activating of CaSR.