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@#【Objective】The aim of this study is to investigate whether Fuzi polysaccharide（FPS）inhibits calcification of vascular smooth muscle cells（VSMC）and its underlying mechanism involving ceramide signaling.【Methods】We used Ox- LDL to induce in vitro model of human VSMC calcification in this study. FPS at different concentrations was used to treat human VSMC. Cell calcification was assessed by alizarin red staining. The mRNA expressions of osteogenic differentiation markers including Msx2，Osterix and BMP2，and contractile marker SMA were analyzed by qRT- PCR. The protein expressions of Msx2 and BMP2 were analyzed by western blot. Cell apoptosis was examined by TUNEL. Additionally，we investigated the effect of FPS on ceramide levels and N- SMase activity in VSMC. 【Results】We found that FPS inhibits Ox- LDL- induced VSMC apoptosis and calcification. Ceramide participates in Ox- LDL- induced apoptosis and calcification of VSMC. FPS reduces N- SMase activity and ceramide levels in Ox- LDL- treated VSMC. Collectively ， reducing N-SMase activity and ceramide levels could become a promising strategy for the treatment of vascular calcification.【Conclusion】We demonstrate that FPS attenuates VSMC calcification via targeting ceramide signaling.
RESUMO
Objective To observe the expression of Klotho and Na+/Pi cotransporter in high phosphorous-induced rats with 5/6 nephrectomy and its relationship with vascular calcification,as well as to investigate the effect of early intervention by sodium thiosulfate (STS) on the progression of vascular calcification.Methods Either 5/6 nephrectomy (n=21) or sham operation (n=14) was conducted on 35 Sprague Dawley rats,who were then fed with high phosphorus (HP) diet or normal phosphorus (NP) diet for 16 weeks respectively.The rats were divided into 5 groups as follows:(1) remnant kidney rats receiving HP diet (NHP,n=7),(2) remnant kidney rats receiving NP diet (NNP,n=7),(3) sham operation rats receiving NP diet (SNP,n=7),(4) sham operation rats receiving HP diet (SHP,n=7),(5) remnant kidney rats receiving HP diet with STS (THP,n=7).The treatment group was given STS intraperitoneally three times a week for 16 weeks.At the end of the 16th week,rats tail artery blood pressures were tested,serum creatinine (Scr),calcium (Ca2+),phosphorus (P3+),FGF23,iPTH and urine protein were examined.Throacic aorta and kidney were then removed.Vascular calcification was confirmed by Von kossa staining.Klotho and Pit-1 expression in aortas were determined by immunohistochemistry.Renal lesion was determined by PASM-Masson staining.Renal Klotho and NaPi-2a mRNA were determined by real time RT-PCR.Results After 16 weeks,Scr,p3+,FGF23,iPTH,uric protein and blood pressure were significantly higher in NHP than those in SNP rats (all P ＜ 0.05).PASM-Masson staining revealed typical renal pathology of chronic renal failure in NHP group.With the treatment of STS,THP rats showed significant decrease in Scr,t3+,FGF23,iPTH,uric protein and blood pressure by comparison with NHP group (all P ＜ 0.05).Significant vascular calcification was found in NHP group while NNP and SHP group occasionally had vascular calcification;THP group had marked alleviation of vascular calcification.The aorta and renal expression of Klotho decreased remarkably while expression of Pit-1 and NaPi-2a increased significantly in NHP compared with SNP group (all P ＜ 0.05).Accordingly,the aorta and renal expression of Klotho increased and Pit-1 and NaPi-2a decreased significantly in THP compared with NHP group (P ＜ 0.05).Conclusions The early intervention of sodium thiosulfate might regulate Klotho and Na +/Pi cotransporter expression in both aorth and kidney,decreasing serum phosphate,delaying progression of vascular calcification and improving renal function.