脑出血大鼠脑内转化生长因子β_1表达的研究

The research on expression of transforming growth factor β_1 protein and mRNA in rat brain with intracerebral hemorrhage

目的 探讨脑出血大鼠脑内转化生长因子β1（TGF-β1）蛋白和mRNA表达的规律.从而为脑出血后神经功能的修复提供理论依据.方法 将75只SD大鼠随机分为3组：正常对照组（5只）,假手术组（35只）,模型组（35只）,通过立体定位向脑内苍白球注入Ⅶ型胶原酶,以建立大鼠脑出血模型,用免疫组织化学及原位杂交法检测脑出血后大鼠脑内的TGF-β1表达变化.结果 TGF-β1在脑出血3 h已明显表达,6 h表达进一步明显增强,但在12h表达下降,而在1天后第2次升高达到高峰,4～7天减少,14天后消失.在脑出血6 h,TGF-β1主要在神经元表达,部分在小胶质细胞,但没有发现在星形胶质细胞表达.TGF-β1在脑出血早期是全脑普遍性表达,以海马CA1和CA3及3～5层的皮质锥体细胞明显,后期则主要是在血肿周围表达.结论 脑出血后大鼠脑内TGF-β蛋白和mRNA表达的增强,这可能是神经功能修复的主要机制之一.

Objectives To explore the expression of transforming growth factor β1 （TGF-β1）protein and mRNA in rat brain with intracerebral hemorrhage （ICH） and to supply theoretic evidence of rehabilitation of neural function. Methods Seventy-five Sprague-Dawley （SD）rats were randomly divided into three groups, normal group, sham operation group and model group. The ICH model was established by injecting collagenase type-Ⅶ stereotaxically into right globus pallidus. The distribution of TGF-β1 expression was investigated using immunohistochemistry and in situ hybridization. Results The expression of TGF-β1 began obviously at 3 h, increased at 6 h, but decreased at 12 h. It reached the peak for the second time after 1 day, decreased after 4 to 7 days, and disppeared after 14 days. Expression of TGF-β1 protein was found mainly in neurons, partly in microglia, but not in astrocytes before 6 h of ICH. Later the expression became more and more obvious in microglia and existed only in intact neurons. The TGF-β1 expression was distributed in whole brain,especially in the areas exhibiting sensitive vulnerability to cerebral ischemia such as CA1, CA3 of hippocampus and 3 to 5 cortical pyramidal cell layers in the early ICH phase, but in the later phase its expression was mainly located in hematoma and perihematoma regions. Conclusions The increased expression of TGF-β1 in rat brain after ICH is probably one of the main mechanisms for rehabilitation of neural function.