大鼠额叶皮质损害后诱导型iNOS阳性细胞的变化

Change of inducible nitric oxide synthase cells after frontal cortex injury

目的 :一氧化氮在脑内的许多生理功能中起重要作用 ,并参与脑损伤的病理生理过程。本研究旨在探讨实验性脑损伤后的NOS阳性细胞的来源及成份。方法 :利用机械抽吸法制成大鼠额叶皮质损伤动物模型 ,应用NADPH d组织化学及GFAP免疫组化法观察损伤后 1、3、7、14、2 1、3 0及 60d皮质损害区NOS阳性细胞的类型和变化。结果 :损害后 1d即见皮质损害区底部和两侧nNOS阳性细胞增加 ,损害底部出现诱导型胶质细胞 ,尤以胼胝体中更为密集。这种反应 3～ 7d时逐渐增强 ,2周时最明显 ,以后随时间推移及损害的修复而降低 ,研究发现部分iNOS阳性细胞与GFAP者共存 ,提示系反应性胶质细胞 ,未见eNOS阳性细胞上调现象。结论 :皮质受损时 ,出现 2种不同表型的NOS阳性细胞且上调 ,即出现诱导型神经元nNOS和诱导型iNOS胶质细胞。究其来源各不相同 ,但均能合成NO ,NO主要集中在损伤部位的周围。

Objective:To investigate the cellular sources and com ponent of nitr ic oxide(NO)/nitric oxide synthase(NOS) after experimental brain injury in rats. Methods:Focal brain traumas were made by gentle aspirati on at the right frontal cortex on rats.Then these animals were killed at 1,3,7,14,21,30 and 60 days respectively after being injured.Brain sections were analyzed by NADPH-diaphor ase histochemistry and GFAP immunohistochemistry.Double staining assays were use d to determined which cells produced the inducible NOS.Result:At one day after l esion the NADPH-d positive neurons were seen surrounding the woud cavity with i ntense aggregated iNOS positive glial cells at the bottom of the wound cavity,an d in the corpus callosum iNOS expression was at its maximal intensity.These reac tions got more intense gradually from 3 to 7 days and reached most intense at tw o weeks,and were decreased with the wound being repaired.Part of the iNOS positi ve cell coexisted with GFAP,which suggested that these cells were reactive astro cytes.No upregulated eNOS positive cells were seen in the wound area.Conclusion: Two different isoforms of NOS positive cells (the neuronal and inducible glial i soforms) present around the wound cavity.The sources of these cells are differen t.These results suggests that NO may be an endogenous modulator that has a ben eficial affect on repairing the wound.