IGF-I und TGF-β1 stimulieren die Osteoblastendifferenzierung und nicht deren Proliferation

Abstract

Growth factors are known to stimulate bone regeneration and fracture healing. Previous studies revealed a stimulating effect of locally applied IGF-I and TGF-βI from Poly(d, l-lactide) coated titanium implants on fracture healing in rat and pig [1, 2]. The purpose of this study was to evaluate the effect of the growth factors IGF-I and TGF-βI and the PDLLA-coating on osteoblasts in cell culture. The human osteoblast cell line hFOB 1.19 was used in the study. The cells were incubated for 10 days in total and the implants (n = 6 each group and time point) were added for 12 h, 24 h, 2 d, 4 d, or 10 d. To analyze a possible effect of the growth factors or the coating, cell proliferation, metabolism and differentiation were investigated. The collagen I production was chosen as an indicator for differentiation. All experimental groups showed comparable cell vitality and no changes in the pH of the medium was detectable between the analyzed groups. Comparing the effect of the titanium implant and the PDLLA coating with the control culture no differences in proliferation, metabolic activity and collagen I production were detectable. The osteoblasts treated with IGF-I and TGF-βI released from PDLLA revealed a significantly enhanced collagen I production with a decrease in proliferation and metabolic activity compared to the control. No significant differences in collagen I production were seen due to the incubation time points. None of the experimental groups evoked an immunological response on mouse macrophages. In conclusion, the PDLLA-carrier showed no negative effect on osteoblasts, whilst the incorporated growth factors stimulated osteoblast differentiation.