大鼠液压冲击脑损伤TGF-β1及其受体TβR I的表达

目的观察脑损伤后TGF-β1及其受体TβRI蛋白表达及其时序性变化,探讨脑损伤的分子机制及法医学脑损伤时间推断。方法用免疫组织化学方法观察大鼠液压冲击脑损伤后TGF-β1及其受体TβRI蛋白在伤后不同时间(30 min、1 h、3 h、6 h、12 h、1 d、3 d、7 d)的表达情况,以正常大鼠及手术大鼠作为对照。结果 (1)正常及手术对照组大鼠脑组织内有低水平的TGF-β1及TβRI表达;(2)脑损伤后1～3d,大脑皮质和脑干TGF-β1/TβRI蛋白表达逐渐增加,7 d时仍维持在高表达水平;(3)海马冲击后12 h～1 d逐渐增加,3 d时仍处于高表达水平,7 d时已开始下降。结论脑损伤可诱导TGF-β1/TβRI基因在脑内表达,其时序性改变可望用于法医学脑损伤时间推断。

The expression of TGF-β1 and type I receptor following moderate lateral fluid percussion brain injury in rats

Objective Study on the pattern of changes of TGF-β1 and type I receptor occurred in the experimental fluid percussion brain injury model for the purpose of providing the scientific basis for molecular pathological diagnosis, forensic identification, clinical treatment as well as further ascertaining the molecular mechanism of brain injury. Methods Male Sprague-Dawley rats were divided into normal control, sham operation control and injury groups. The rats of injury groups were subjected to moderate lateral fluid percussion brain injury (0.2 MPa). The injury groups were then subdivided into 30min, 1h, 3h, 6h, 12h,1d, 3d and 7d sub-groups according to the time elapsed after injury. Immunohistochemistry SP method was used for studing the immunoreactivity of both TGF-β1 and TβR I factors. Results (1) In the brain of normal control and sham operation control groups, the low expression levels of TGF-β1 and TβR I were observed; (2) The gradual increase of TGF-β1 and TβR I immunoreactivity could be observed 1 to 3d after injury both in cortex and brain stem, and sustained at the high level up to 7d; (3) In hippocampus, the gradual increase occur during 12h to Id after brain injury, and sustained the high level at 3d, then declined at 7d. Conclusion The results suggested that brain injury induced the gene eypressions of the TGF-β1/ TβR I . The TGF-β1/ TβR I may contribute to maintance of nerve cell survival and the repair of damaged neural tissues after CNS injury and the patterns of their level change were quite regular and can be used for timing of injury in forensic medicine aspect.