mRNA expression of transforming growth factor β1 in inducing osteogenesis of bone morphogenetic protein

Objective Through observing the mRNA expression of transforming growth factor β1 (TGF-β1) in the course of bone morphogenetic protein (BMP) inducing osteogenesis, to investigate whether some other growth factors have taken part in the courses of inducing osteogenesis of BMP, so to expound the inducing mechanism of BMP. Methods An experimental model of 12 mm bone defect in the left ulna of 16 rabbits was adopted. These rabbits were divided into experimental group and control group at random. Specially treated bovine cancellous was adopted as a carrier of BMP. BMP 10 mg/carrier and carrier only were implanted into the bone defect area of experimental group and control group, respectively. Tissues in the bone defect area was extracted from both the experimental and control groups on the 3rd,7th,14th, and 21st day, respectively. An in situ hybridization method was used to detect the mRNA expression of TGF-β1, and to analyze the mRNA expression using image analysis. Results TGF-β1 mRNA expression was seen in both experimental and control group at the early stage after implantation. The peak mRNA expression of TGF-β1 of the experimental group appeared on the 14th day, accompanied by numerous chondrocytes and osteoblasts. Image analysis found that the TGF-β1 mRNA expression was significantly higher in experimental group than in control group at same time phases. Conclusions The mRNA expression of TGF-β1 is found in the course of BMP inducing osteogenesis. BMP has the effect of promoting the formation and secretion of TGF-β1. TGF-β1 and some other growth factors may be needed in inducing osteogenesis of BMP.