Experiment Of The Effect Of NGF On Rat's Bone Defect Healing

Objective:To investigate the effect of NGF on the segmental bone defect, and to study the role of BMP-2 inducing osteoblast formation.Methods:60 SPF Wistar rats, weight 200～220g, divided into 4 groups randomly with the envelope method,15 rats each group, established the bone defect model 4 mm in the right upper middle tibia, group A,B,C,D's bone defects were locally implanted with NGF/blank gelatin sponge, normal saline/BMP-2-gelatin sponge, NGF/BMP-2-gelatin sponge, normal saline/blank gelatin sponge respectively. Postoperation 4W,8W,12W time, took out five rats of each group, undergone a venous blood sampling for alkaline phosphatase, x-ray of the defect part, taken gross specimens, calcium content and histology examination.Results:At the same time point postoperatively, through general observation of the bone defect size, in group A, B and C the new tissues increasing in hardness mainly became cartilage and bone tissue, in group D, the new tissues were softer, in which granulation tissue and fibrous tissue were mainly seen. Through X-ray observation, group A, B and C showed increasing blurring of the bone defect parts vertically and horizontally, group D showed a clear defect. Through osteogenesis ashes value, the calcium content of the callus were higher in group A,B, and C, compared to group D, there were a significant differences of the calcium content of the callus in which group B compared to group C and group A compared to group D (P<0.05). The serum ALP content were increased in each group, reached its peak at 8th week, whereas group C was the highest, and there was significant differences of the serum ALP content compared to the other groups (P<0.01), the ALP level went down at the 12th week. From the same time points postoperatively, through histology examination, group A, B and C showed increased of the bone trabeculae maturity and density in which better than group D, the bone density was gradually increased longitudinally, in group D, fibrous tissues were mainly seen.Conclusion:NGF can promote bone growth in bone defect part, and can cooperate with BMP-2 to induce osteogenesis ability.