The therapeutic effects of BMP-2 and IGF-1 on fracture healing in diabetic rats

Our objective is to explore the effects of BMP-2 and IGF-I in promoting fracture healing in diabetic rats. First 30 rats were made into fracture model with diabetes and randomly divided into 2 experimental groups, the rats in group A ́ received insulin growth factor-1 (IGF-1) combined with fibrin glue and the rats in group B ́ received bone morphogenetic protein-2 (BMP-2) combined with fibrin glue. The rats without any treatment after model establishment were set as control (group A). At 2, 4 and 6 weeks after the surgery, the X-ray of left lower limb was taken, the bone mineral density (BMD) of local fracture site and callus was detected, the fracture healing was observed, the tissue from the end of fracture was observed by hematoxylin-eosin (H&E) staining, the blood glucose and alkaline phosphatase (ALP) were detected, the osteocalcin (OC) was detected by radioimmunoassay, the local BMP-2, IGF-1 and OC were detected by immunohistochemistry and the collagen type I expression was detected by real time polymerase chain reaction (RT-PCR). All the data were analyzed. In the results, Compared with group A, in group A ́ and B ́ the ALP and OC were significantly increased, which was highest in the 2nd week, and there was no difference in the 6th week; X-ray results showed that the callus was increased, the BMD values were slightly increased; RT-PCR results showed that the collagen type I in local callus was increased which was most significantly in 2nd week and there was no difference in 6th week. Compared with group B ́, the collagen type I in local callus tissue in group A ́ was slightly higher which was most significant in 2nd week and there was no difference in 6th week. In conclusion, under the same condition, IGF-I or BMP-2 combined with fibrin glue applying at the end of fracture can significantly improve the fracture healing, and IGF-1 has better effects. Local application of fibrin glue combined with BMP-2 or IGF-I for treating fracture in diabetic rats cannot effectively increase the BMD values in the fracture end and callus.