A study on calcification of cultured aortic medial cells in vitro

Objective To investigate calcification of cultured aortic medial cells in vitro and acceleration by 25 hydroxycholesterol or β glycerophosphate. Methods Aortic medial cells were obtained by explantation, and the calcification was observed by von Kossa staining. Insoluble calcium precipitation in cellular layer was determined by biochemical method , and osteocalcin in the media was analyzed with radioimmunoassay. Results Two different types of primary cells were shown from culture: one with parallel cellular growth and being negative by von Kossa staining, the other cell type formed cellular nodules with positive von Kossa staining. After 28 days of cell passages, cell growth appeared no nodule formation. However, many cellular nodules and positive von Kossa staining were observed in the passaged cells treated with 25 hydroxycholesterol or β glycerophosphate, and both insoluble calcium 〔(57 80±18 50)μg/pool, (67 50±15 30)μg/pool〕and osteocalcin 〔(0 886±0 063)μg/L, (0 895±0 061)μg/L〕in the medium were significantly increased than that of the untreated cells. Conclusions Cultured aortic medial cells could be divided into two subtypes, one with the characters of smooth muscle cells, the other with the micro vascular pericytes which could calcify the extracellular matrix. 25 hydroxycholesterol and β glycerophosphate promoted the in vitro calcification, and osteocalcin secretion was increased in the process of calcification of aortic medial, suggesting that osteocalcin might participate in the aortic calcification.