大鼠脑出血后血肿周围脑组织p75NTR的表达及其与细胞凋亡的关系

目的研究大鼠脑出血后不同时期血肿周围组织中p75NTR的表达规律及与其细胞凋亡的相关性。方法采用自体动脉血注入右侧尾状核制备大鼠脑出血动物模型，分别于脑出血后6h、24h、72h和10d处死大鼠获取血肿周围脑组织标本，通过流式细胞仪检测细胞凋亡率，免疫组化法及实时荧光定量PCR检测p75NTR蛋白及mRNA的表达。结果脑出血后6hpp75NTR蛋白和nRNA表达水平即上升，24h继续升高，72h到达高峰，至10d仍维持在较高水平，与对照组相比均差异显著（P〈0．05）。脑出血后细胞凋亡率的动态变化趋势与p75NTR蛋白及mRNA表达变化一致，两者之间呈显著正相关（P〈0．05）。结论脑出血后p75NTR可能参与介导脑细胞凋亡。

Relationship between expression of p75NTR and cell apoptosis in rat cerebral tissues around hemotomas after intracerebral hemorrhage

Objective To investigate the relationship between expression of neurotrophin receptor p75 （p75NTR） and cell apoptosis in rat cerebral tissues around the hemotomas after intracerebral hemorrhage （ICH）. Methods Fifty SD rats were divided into 2 groups, i. e. control group （n=10） and ICH group （n=40）. The animals in ICH group were then re-divided into 4 subgroups, of which the animals were sacrificed 6 hours, 24 hours, 72 hours and 10 days after ICH respectively. ICH model was made by the injection of autologous arterial blood （80 μ1） into the right nuclei caudate in all the ICH subgroups. The cerebral tissues around the hemotomas were isolated from the brains and cell apoptosis was detected by flow cytometry in all the groups. The immunohistochemical technique and real-time PCR were used to assay the protein and mRNA expressions of p75NTR in the cerebral tissues around hemotomas. Results The levels of p75NTR protein and mRNA expressions and the rate of cell apoptosis significantly increased in all the ICH subgroups compared to those in the control group （P〈0.01）, and they reached the top 72 hours after ICH and then they gradually decrease, but they still were significantly higher 10 days after ICH than those in the control group （P〈0.01）. The levels of p75NTR protein and mRNA expressions were significantly positively correlated with the rate of cell apoptosis （P〈0.01） in the cerebral tissues around the hemotomas. Conclusion The cell apoptosis in the cerebral tissues around the hemotomas after ICH may be mediated by the increase in the expression of p75NTR.