关键词: 脑外伤, 骨折愈合, 血管内皮生长因子, 酶联免疫吸附法, 免疫组织化学

Abstract: Objective To study the relationship between vascular endothelial growth factor(VEGF) and enhanced osteogenesis after cerebral trauma by investigating the level of VEGF in serum and the expression of VEGF in granulation tissue of fracture region in patients with fracture and cerebral trauma. Methods Totally 57 patients who were treated in our hospital were included(the position and type of fracture were similar, which were extremity long bone fractures). ELISA and immunohistochemical methods were used for determination of VEGF. The 57 patients were divided into two groups: group A, fracture group(n=31); and group B, fracture with cerebral trauma group(n=26), and the serum of all patients were collected at weeks 1, 2, 3, and 4. The concentration of VEGF in serum was detected by ELISA method. Immunohistochemical staining: The 31 patients of group A and the 26 patients of group B were further divided into A₁(n=10), A₂(n=11), A₃(n=10) and B₁(n=8), B₂(n=8), B₃(n=10) according to the time from injury to operation(3~7 d, 8~14 d, 15~21 d). Samples of granulation tissue of fracture site of each patient were collected during surgery, taking immunohistochemistry staining method to calculate positive cell rate and gray scale value of VEGF. Results 1) ELISA: The concentration of VEGF in serum of group A(fracture group) was low at the first week, and it reached the maximum value at the second week and decreased obviously at the fourth week; while it reached the maximum value at the first week in group B, after that although it decreased but still maintained a high level, and decreased obviously in the fourth week. The concentration of VEGF in serum of group B was significantly higher than that of group A at the same time-point(1-3 week)(P<0.05), and there was no significant differences between two groups at the fourth week(P>0.05). 2) Immunohistochemical staining: The expression of VEGF in group A was very low from 3~7 d, and it reached the peak at 14 d and decreased slightly during 15~21 d. The expression of group B started to increase on d 3 after injury, and it rose to the peak at 7 d and stained a high level through 15~21 d. At the same timespan, positive cell rate and gray scale value of VEGF in group B was significantly higher than that in group A(P<0.05). Conclusion The level of VEGF in serum and the expression of VEGF in granulation tissue of fracture region in patients with fracture and cerebral trauma was persistently higher than that in patients with fracture only in the progress of fracture healing, and the enhanced osteogenesis caused by cerebral trauma may be implemented mainly through promoting the expression of many growth factors, such as VEGF.

Key words: cerebral trauma, fracture healing, vascular endothelial growth factor, ELISA, immunohistochemistry