Effects of insulin-like growth factor on expression of osteopontin in rat vascular smooth muscle cells

AIM To explore whether or not the function of insulin like growth factor (IGF I) in promoting osteopontin gene expression and protein synthesis of rat vascular smooth muscle cell (VSMC). METHODS Cultured cells were incubated with different concentration of IGF I for different hours, then RT PCR and Western blotting analysis were used to observed the effects of IGF I on osteopontin expression of rat vascular smooth muscle cells RESULTS IGF I (20 μg·L -1 ) could obviously induce the gene expression and protein synthesis of osteopontin, RT PCR results showed that the ratio of mRNA of osteopontin and β actin in cells incubated with IGF I (20 μg·L -1 ) for 3, 24 and 48 h increased by 39 70%,40 44% and 54 05% respectively, as compared with that of the control ( P 0 05), and Western blotting analysis also showed that protein synthesis of osteopontin in cells incubated with IGF I for 3, 24 and 48 h increased by 53 30%,1 15 times and 1 25 times respectively, as compared with that of the control ( P 0 05) CONCLUSION IGF I could stimulate osteopontin gene expression and protein synthesis of rat vascular smooth muscle cells