Investigation for TGF-β1 expression in type 2 diabetes and protective effects of TGF-β1 on osteoblasts under high glucose environment.

OBJECTIVE: The occurrence rate of delayed fracture healing in diabetes mellitus patients is high. Transforming growth factor β1 (TGF-β1) is an important regulatory factor in bone tissue repair and regeneration. However, TGF-β1 expression and its function in diabetic patient fracture have not been fully elucidated.

PATIENTS AND METHODS: Type 2 diabetes fracture patients (T2DM group), fracture patients without diabetes (non-T2DM group), and healthy volunteers (Control group) were selected for the research. TGF-β1 expression in peripheral blood was detected by using enzyme-linked immunosorbent assay (ELISA). Osteoblast cell line, MG-63 cells, were randomly divided into Control, high glucose group, and TGF-β1 group. TGF-β1 expression was evaluated by using Real Time-PCR (RT-PCR). Cell proliferation was evaluated by using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Cell apoptosis activity was determined with caspase-3 activity and flow cytometry assay. The effect of TGF-β1 on NF-κB was detected by using Western blot.

RESULTS: TGF-β1 was significantly reduced in patients of T2DM and non-T2DM groups compared with Control (p<0.05), while it was lower in T2DM group (p<0.05). TGF-β1 expression was declined, cell proliferation was inhibited, caspase-3 activity was enhanced, cell apoptosis was elevated, and NF-κB expression was reduced in MG-63 cells of high glucose group compared to Control group (p<0.05). TGF-β1 significantly promoted cell proliferation, suppressed caspase-3 activity, alleviated cell apoptosis, and elevated NF-κB expression in MG-63 cells compared with high glucose group (p<0.05).

CONCLUSIONS: TGF-β1 decreased in diabetes fracture patients. Up-regulation of TGF-β1 regulates cell apoptosis and caspase-3 activity, and it facilitates osteoblasts proliferation.