Effects Of NGF Of Local Injection On OB Proliferation And Expression Of OC In Osteotylus Of Diabetic Rats With Fractures

Research objective:To establish the model of diabetic rats with fracture and investigate effects of NGF on fracture healing of diabetic rats by detecting OB proliferation and expression of OC in osteotylus tissues.Material and method:Forty eight2-month-old male SD rats were randomly divided into NGF-treated group, diabetes model group and normal control group. The rats in diabetes model group and NGF-treated group were given once intraperitoneal injection with streptozotocin at dosage of50mg/kg and the rats in normal control group with physiological saline of the same volume in the same way. After three days of injection,the rats whose random blood sugar exceeded16.8mmol/L were brought into diabetes model group and NGF-treated group.Tibia fracture model of rats was established in the right upper tibia of three groups.The rats in NGF-treated group were given a daily right gastrocnemius muscle intramuscular injection with NGF at dosage of2000AU (1.4μg) and the rats in normal control group and diabetes model group with physiological saline of the same volume in the same way,lasting1week. At1,2,4,6weeks post-fracture, the fracture healing of tibial bone was observed by X-ray plain films,the OB amount in the osteotylus tissues was performed under light microscopy,the Ki67index was detected by immunohistochemical staining and serum OC expression was detected by radioimmunoassay. Results:At the same time point post-fracture, X-ray films showed a large amount of osteotylus tissues produced in the NGF-treated group and normal control group, and the fracture healing was superior to that in the diabetes model group (P<0.05). Light microscopy observation displayed that the osteoblast number in the NGF-treated group was greater than that in the diabetes model group, and was slightly lower than that in the normal control group. The Ki67index of three groups were increasing, reached a peak value at2weeks, the Ki67index was at2weeks (17.76±0.20)%in the diabetes model group,that of the NGF-treated group was (27.56±0.65)%and that of the normal control group was (28.91±1.32)%,decreased at4weeks and further decreased at6weeks. The Ki67index of the diabetes model group was lower than that of the NGF-treated group and the normal control group (P<0.05).Although the Ki67index of the NGF-treated group was slightly lower than that of the normal control group,there were no significant differences (P>0.05).The serum OC levels of three groups were increasing, reached a peak value at2weeks, decreased at4weeks and further decreased at6weeks. The OC in the model control group was remarkably lower than that in the normal control group (P<0.05). There were no significant differences in the OC level between NGF-treated group and normal control group.Conclusion:1. The OC level and OB proliferation are reduced in the rats with diabetes mellitus during the process of fracture healing.2. NGF can increase OC levels,promote OB proliferation and facilitate fracture healing.