Basic Study
Effect and mechanism of magnesium on vascular calcification induced by hyperphosphate
Yaling Bai, Jinsheng Xu, Jingjing Jin, Junxia Zhang, Shenglei Zhang, Liwen Cui, Huiran Zhang
Published 2015-01-15
Cite as Chin J Nephrol, 2015, 31(1): 37-42. DOI: 10.3760/cma.j.issn.1001-7097.2015.01.007
Abstract
ObjectiveTo explore the effect and mechanism of magnesium on calcification induced by hyperphosphate.
MethodsVascular smooth muscle cells (VSMCs) were primarily cultured in vitro and induced calcification by β-glycerophosphate (β-GP). VSMCs were randomly divided into control group, high phosphorus group (10 mmol/L β-GP), magnesium intervention group(10 mmol/L β-GP+3 mmol/L MgSO4) and 2-aminoethoxy-diphenylborate (2-APB, an inhibitor of magnesium transporter) intervention group(10 mmol/L β-GP+3 mmol/L MgSO4+10-4 mol/L 2-APB). Calcium deposition and alkaline phosphatase (ALP) activity were measured by alizarin red staining, quantification of calcium and enzyme linked immunosorbent assay. RT-PCR and Western blotting were used to observe the expression of core binding factor α-1 (Cbfα-1) mRNA and protein, respectively. In vivo, male Sprague-Dawley rats (n=24) were randomly divided into control group (methylcellulose+high phosphorous diet), vascular calcification group (adenine suspension+high phosphorous diet), high magnesium intervention group(adenine suspension+high phosphorous and magnesium diet). The aortic pulse wave velocity (PWV) was measured, and vascular calcification was determined by von Kossa stain and quantification of calcium. Cbfα-1 in aortic was measured by immunohistochemistry.
ResultsIn vitro, compared with high phosphorus group, calcification, ALP activity (P<0.05) and Cbfα-1 expression in VSMCs were significantly decreased in magnesium intervention group after incubation for 14 days, but the addition of 2-APB might inhibit the protective effect of magnesium on VSMCs. Dynamic observation of Cbfα-1 showed that magnesium significantly inhibited the expression of Cbfα-1 (P<0.05) on the third day and the inhibitory role was obviously increased in a time-dependent manner. Consistent with the findings in vitro, the aortic PWV, calcification were all significantly reduced (P<0.05) in high magnesium intervention group with high serum magnesium level, when compared with vascular calcification group. Immunohistochemistry showed that hypermagnesemia down-regulated obviously the expression of Cbfα-1 induced by hyperphosphatemia(P<0.05).
ConclusionMagnesium protects against vascular calcification by inhibiting osteogenic differentiation of VSMCs.
Key words:
Magnesium; Calcification; Chronic renal failure; β-glycerophosphate; Core binding factor alpha 1
Contributor Information
Yaling Bai
Department of Nephrology, The Forth Hospital of Hebei Medical University, Shijiazhuang 050011, China
Jinsheng Xu
Jingjing Jin
Junxia Zhang
Shenglei Zhang
Liwen Cui
Huiran Zhang
