BACKGROUND: Recently, there are some researches show that the nutrition and control of nervous system play an important role in the growth of bone and healing of bone fracture.OBJECTIVE: To probe into the effects of brain-derived neurothophic factor on bone fracture healing and its biomechanic features.DESIGN: Randomized controlled study of experiment animals.SETTING: Traumatic orthopaedic and hematology department of a military medical university.MATERIALS: There were 16 SD rats with transverse fracture of shin,which were set up as intramedullary nail internal fixation. They were randomly divided into experiment group and control group with each of 8 mice.INTERVENTIONS: Rats in the experiment group were taken subcutaneous injection of brain derived neurotrophic factor(BDNF) every other day while control group was injected of saline. The shin of mice was collected to observe in the 2nd, 3rd, 4th and 5th weeks.MAIN OUTCOME MEASURES: Gross comparison of fracture healing of each group, biomechanical test and electro microscopic observation.RESULTS: It can be seen by gross observation 2 weeks after operation that the fracture area was linked by connective tissue in both groups and there was obvious movement. In the 3rd week, woven like bone healing could be seen in the experiment group whereas there was obvious fracture end movement in the control group. In the 4th week, bone healing could be seen in both groups, but the bone callus in the experiment group was much smaller with mild angled malformation. In the 5th week, the fracture line in the experiment group already disappeared and the molding of bone fracture was good while there was bigger bone callus in fracture end of the control group. The angle formed by sagittal planes of fracture in the 3rd, 4th and 5th week was(25.00 ± 1.82)°, (24.75 ± 2.50)°, (23.25 ± 3.77)° respectively in the experiment group and(32.00 ±2.45)°, (33.00 ±5.72)°, (29.25± 2.22)° respectively in the control group( P ＜ 0. 05) . The anti-fracture stress in each stage of the experiment group was better than that of the control group( P ＜ 0.05).CONCLUSION: Applying BDNF early and incessantly can stimulate all the stages of bone fracture healing.

Objective To study the expression of nerve growth factor (NGF) in sensory and motor Schwann cells and its significance in the nerve specific regeneration Method Sensory and motor Schwann cells were prepared in vitro,and each group of cells were cultured in common media and IL 1 media respectively The expression of NGF was measured by Sangwich ELISA Result Generally speaking,the expression level of sensory Schwann cells is higher than that of motor cells And the expression modes of the two types of cells are different,according to the timing and peak numbers Conclusion The NGF expressions of sensory and motor Schwann cells are different,such a difference may partly explain the mechanism of the nerve specific regeneration

Objective:To observe the effect of allogeneic MHC Ⅰ gene modification on the immunologic character in bone marrow cells and to investigate the mechanism of induce immunologic tolerance of MHC Ⅰ.Methods:The retroviral expression vector of BALB/C mice H 2D d gene was constructed and transducted into C57BL/6 mice bone marrow cells And the expression of H 2D d on the infected cells was detected by FACS technique Then observe the MLR between the BALB/C mice spleen T cells and the C57BL/6 mice bone marrow cells modified with H 2D d gene by MTT assay The cytotoxic activity of BALB/C mice NK cells to the C57BL/6 mice bone marrow cells modified with H 2D d gene was detected by LDH release assay Results:Either stimulation or response ability of the C57BL/6 mice bone marrow cells to the T cell from BALB/C mice spleen was significantly decreased after modified with H 2D d gene The cytotoxic activity of BALB/C mice NK cells to the C57BL/6 mice bone marrow cells modified with allogeneic MHC Ⅰ gene was significantly lower than which to the C57BL/6 mice bone marrow cells non modified Conclusion:It's maybe a way to induce immunologic tolerance in bone marrow transplantation by the means of modify the bone marrow cells with the MHC Ⅰ gene of the recipient