| Objective: To analyze the changes in the expression levels of serum Neuritin and Neuritin in callus of femoral fracture after brain injury in SD-rats, and to investigate the relationship and mechanism of central nervous system injury on fracture healing, in order to provide theoretical foundation for the treatment of refractoriness fracture for clinical selectivity.Methods:A total of ninety-six healthy male Sprague—Dawley(SD) rats were selected and were randomly divided into four groups:group A, negative control(n=8); group B, only femoral fractures in 40 rats(n=40); group C, cerebral trauma group(n=8); and group D, fracture with cerebral trauma group (n=40). The rat model of fracture was established by surgery: to expose one side of femoral, and Kirschner wire of 1.0mm in diameter was used for fixation after the middle of femoral were made fracture by saw and Using modified hydraulic equipment, the rat model of cerebral trauma was established.8 rats in each of group were randomly selected,2ml venous blood of the rats were taken at day 3,week 1,2,3and4after the operations and centrifugated to get the serums. The parts of fracture were examined with X-rays to observe the reparative process and effect and put to death at an estimate time. The changes in the expression levels of serum Neuritin were detected by enzyme linked immunosorbent assay (ELISA) method. Eight rats in each of group B and D were randomly selected at an estimate time and osteotylus samples were obtained. Tissues at one centimeter away form broken ends above and below the callus of femoral fracture were stained by HE and immunohistochemistry to observe the expressions of Neuritin in callus and the fracture healing.RESULTS:All 96 Sprague-Dawley rats were involved in the final analysis:①-ray and figure showed that fracture with cerebral trauma group accelerate the faster process of fracture than only femoral fracture.②The hematoxylin and eosin staining indicated that the process of fracture healing was classical in the simple fracture group, but D group, the callus formation and reforming were ahead of schedule in any time and the accelerated fracture healing was observed.③The immunohistochemical staining indicated that the positive expression of Neuritin was strong in the cytoplasms of the fibroblasts, the mesenchymal cells, the vascular endothelial cells, the early-stage chondrocytest and the osteoblasts, with a higher color intensity. The number of the positive cells was greater in Group D than in Group B. There was a statistical difference between Group D and other Groups(P<0.05)at 3d to 3w after surgery. At 4w after surgery there wasn't a statistical difference between Group D and other Groups(P>0.05).④The concentration of serum Neuritin:At the same time-point, it was higher D group than that in the normal control group simple fracture group and in sample brain injury, while it was similar C group and D group, and Neuritin was similar in A group and B group. Neuritin serum density value in A group (81.37±1.37),B group C group and D group increased to (94.94±3.77 107.28±3.46 118.35±1.43) at 3d after surgery, reached its maximum in two week(110.18±1.48 131.89±3.26 161.48±1.46), and then began to decline, and declined to (89.69±2.05 94.03±3.31 106.66±2.39) in the 4th weeks. There was statistical significance in the expression of the lever of Neuritin in serum is higher in fracture with brain injury group than other groups in certain periods. There was a statistical difference between Group D and other Groups (P<0.05) at 3d to 3w after surgery. At 4w after surgery there wasn't a statistical difference between Group D and other Groups (P>0.05).Conclusion:①More quick healing and more callus of rats fracture after central nerve injury shows that central nerve injury has promoted union of fracture.②The up regulation of Neuritin in callus by immunohistochemical and serums by ELISA may be able to accelerate the process of fracture healing after brain injury. |
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