Observed impacts of insulin therapy on callus cell transforming growth factor-beta 1 expression in diabetic rats

The expression of transforming growth factor-beta 1 (TGF-β1) inside the callus cells of diabetic rats and the impact of insulin therapy on its expression and biomechanics was investigated. The rats were randomly divided as follows: an insulin therapy group (IT), a diabetic model group (DM), and a non-diabetic control group (NC). Bone specimens from each group were extracted at different times for immunohistochemical observation of the expression of TGF-β1. Concurrently, the destruction torque and torsional stiffness were detected at different times. One to four weeks after fracture, TGF-β1 was widely expressed in fractured callus cells and periosteal proliferating cells, while the expression inside diabetic cells was significantly reduced. The expression of TGF-β1 decreased over the first 68 weeks, and the mature bone cells never expressed TGF-β1. The destruction torque (Nm) detected in the 6th week revealed that there was a statistically significant difference between the DM, NC, and IT groups (P < 0.01). In conclusion, TGF-β1 expression was significantly reduced inside the callus cells of diabetic rats. Insulin therapy increased TGF-β1 expression inside the callus cells of diabetic rats and improved the biomechanical characteristics of the callus.