Aim: To investigate the stimulation to in vitro calcification of aorta by 25-hydroxycholesterol or beta-glycerophosphate, and the relationship of the calcification with the secretion of osteocalcin and expression of type X collagen mRNA.
Methods: Aortic medial cells were obtained by explantation. Von Kossa staining was performed to show the in vitro calcification. Insoluble calcium of cellular layer was determined by biochemical method. And osteocalcin in the media was analyzed with radioimmunoassay. RT-PCR was used to determine the expression of type X collagen mRNA.
Results: Passaged cells showed negative von Kossa after 28 days. While cells treated with 25-hydroxycholesterol or beta-glycerophosphate appeared many cell nodules with positive von Kossa staining, in witch much more insoluble calcium and supernatant osteocalcin were detected. Type X collagen mRNA was detected in cells treated with 25-hydroxycholesterol or beta-glycerophosphate but not in untreated cells.
Conclusion: 25-hydroxycholesterol and beta-glycerophosphate can accelerate the in vitro calcification of aortic media. Aortic medial cells secrete more osteocalcin and express type X collagen mRNA during calcification, which is similar to osteoblast, suggesting arterial calcification may share part of the same mechanism with the calcification of the bone.