The Effect Of Bone Morphogenic Protein 2 On Senescence And Calcification In Vascular Smooth Muscle Cells Of Hypertension

Objectives:To study the role of bone morphogenic protein 2(BMP2)in senescence and calcification of thoracic aortic vascular smooth muscle cells(VSMCs)from spontaneously hypertensive rat(SHR)in vitro.Methods: 12 weeks old SHR and wistar-kyoto normotensive rats(WKY)thoracic aorta VSMCs were cultured in vitro.Starting from the third passages of VSMCs,the cells were divide into three group,based on the different mediums which were added with or without rhBMP2 or rm Noggin,set up as follows: the group of SHR-rhBMP2(Group BMP2),the group of SHR-rhBMP2-rmNoggin(Group BMP2+Noggin),Group SHR and Group WKY.Group BMP2 and Group BMP2+Noggin were the experimental groups,Group SRH and Group WKY was the control groups.The levels of senescence and calcification of VSMCs were detected respectively by Senescence ?-Galactosidase Staining and von kossa Staining.The expressions of BMP2?MGP?Runx2 of VSMCs by each passage were detected by immunocytochemistry dynamically and western blot.Results:(1)VSMCs senescent level in every group became more and more serious as time went on.From the 5th passage to the 7th passage,Group WKY were lower than Group SHR(the 5th passage P=0.031,the 7th passage P=0.000).VSMCs from SHR tended to be aged more quickly than those from WKY.(2)The calcification of VSMCs in every group became more and more serious as time went on.Group WKY were lower than Group SHR in each passage(the 3rd passage P=0.006,the 5th passage P=0.033,the 7th passage P=0.000).VSMCs from SHR tended to be calcified more quickly than those from WKY.(3)The expressions of BMP2 in every group increased as time went on.Group SHR washigher than the Group WKY in each passage by immunocytochemistry dynamically(the third passage P=0.007,the 5th passage P=0.000,the 7th passage P=0.000).The level of BMP2 in Group SHR were higher than Group WKY.(4)From the 5th passage,Group BMP2 became higher than Group SHR in the level of senescence(the 5th passage P=0.002,the 7th passage P=0.001),while Group BMP2+Noggin were lower than Group SHR(the 5th passage P=0.036,the 7th passage P=0.007).The rhBMP2 increased the senescence in SHR VSMCs,and Noggin decreased the senescence.(5)From the 3rd passage,Group BMP2 became higher than Group SHR in the level of calcification(the 3rd passage P=0.002,the 5th passage P=0.000,the 7th passage P=0.000).By the 7th passage,Group BMP2+Noggin were lower than Group SHR in the level of calcification(P=0.000).The rhBMP2 increased the senescence and calcification in SHR VSMCs,while Noggin decreased the calcification.(6)The expressions of MGP in every group decreased as time went on.In the 7th passage,Group WKY were higer than Group SHR(P=0.000),Group BMP2 were lower than Group SHR(P=0.001),Group BMP2+Noggin were higher than Group SHR(P=0.000),by immunocytochemistry dynamically.The level of MGP in VSMCs from WKY were higer than from SHR.The rhBMP2 decreased the level of MGP in SHR,while Noggin increased the level.(7)The expressions of Runx2 in every group increased as time went on.In the 7th passage,Group WKY were lower than Group SHR(P=0.001),Group BMP2 were higher than Group SHR(P=0.000),Group BMP2+Noggin were lower than Group SHR(P=0.004),by immunocytochemistry dynamically.The level of Runx2 in VSMCs from SHR were higer than from WKY.The rhBMP2 increased the level of Runx2 in SHR,while Noggin decreased the level.Conclusions:VSMCs from SHR tended to be aged and calcified more quickly than from WKY.BMP2 promoted senescence and calcification in SHR thoracic aortic VSMCs in vitro.Its mechanism may be related to BMP2/Smads/Runx2 signaling pathways and inhibition of MGP expression.