Effects Of Insulin-Like Growth Factor I On Bone Formation Of Cultured Osteoblast Of Cow In Vitro

Objective: To observe the effect of IGF-I on bone formation of cultured osteoblast obtained from the rib of newborn cow in vitro.Methods: To obtain osteoblasts from neonatal cow's rib adopting the method of tissue culture, conduct primary culture and sub-culturing, take the second generation cells as experimental model after identification, and then respectively culture these cells with different concentrations of the IGF-I together. Function of cell proliferation was measured by MTT method (OD value at wave-length 490nm), function of cell differentiation was measured by Golden's method (ALP activity), and function of cell mineralization (mineralized nodes/field of vision) was measured by alizarin red staining method:Results: The tissue mess method is the ideal method to obtain and culture osteoblasts and can be used for the corresponding study. Relatively rarefied osteoblasts could be obtained by means of cell culture in vitro using the method of tissue culture. Five days after communal cultivation, certain concentrations of IGF-I could stimulate the proliferation of the osteoblasts, and the former acted in dose-dependent manner in field of 10μg/L -100μg/L. Contrast with the control group, IGF-I groups could promote the proliferation of the osteoblasts in the concentration of 1μg/L whereas it had insignificant difference with control group (P>0.05). 10μg/L, 50μg/L and 100μg/L groups had significant difference (P<0.05), especially the 100μg/L group(P<0.01), 200μg/L group showed descending tendency. Five days later, the activity of alkaline-phosphotase was increased in experimental groups which were compared with control group respectively, 1μg/L group had insignificant difference (P>0.05) but 10μg/L and 50μg/L group had significant difference (P<0.01). Eighteen days later, contrast with the control group, 1μg/L group had insignificant difference (P>0.05), 10μg/L group had significant difference (P<0.05), 50μg/L group had even significant difference (P<0.01) according to the effect on mineralization.Conclusions: IGF-I can promote bone formation by accelerating the proliferation , the differentiation and mineralization of osteoblasts in vitro. Promoting bone formation of cultured osteoblasts is one of the mechanisms by which IGF-I effectively treat the osteoporosis.