Abstract:

BACKGROUND: It has been still unclear that whether recombinant human bone morphogenetic protein-2 (rhBMP-2) may inhibit production and activity of inflammatory factors, thereby inhibits molecular biomechanism of osteolytic reaction.
OBJECTIVE: To investigate the subcutaneous molecular biological reaction of rhBMP-2 slow-release delivery system in the rat air pouch model, and to analyze the possible mechanism of the inhibition of osteolysis indueced by rhBMP-2.
METHODS: Filtration air (3 mL) was subcutaneously injected into back of rats, once every two days, 6 times in total. One week later, 20 rats were randomly divided into 2 groups, with 10 rats per group. rhBMP-2 low-release formulation and saline were individually injected into air pouch of experimental and control groups. Air pouch tissue was obtained one or two weeks later to measure serum alkaline phosphatase level under optic microscope. Real-time PCR was used to detect extracellular matrix metalloproteinases mRNA level, and Western blotting was used to detect its protein expression.
RESULTS AND CONCLUSION: No tissular and cellular reactions were found in both experimental and control groups. Serum alkaline phosphatase level in the experimental group in 1 week was significantly greater than in experimental group in 2 weeks and control group (P < 0.05), while the level in the experimental group in 2 weeks was less than in the control group, but there was no significant difference (P > 0.05). Extracellular matrix metalloproteinases mRNA and protein expressions in the experimental group were significantly less than in the control group, while the level in 1 week was less than in 2 weeks. The results suggested that rhBMP-2 slow-release delivery system inhibited the production and activities of osteolytic cytokines, so as to inhibit osteolytic reaction.