N-硝基-L-精氨酸甲酯在急性颅脑创伤后对诱导型一氧化氮合酶表达的影响

探讨一氧化氮合酶抑制剂Ｎ 硝基 Ｌ 精氨酸甲酯（Ｌ ＮＡＭＥ）在实验性大鼠脑损伤后对诱导型一氧化氮合酶（ｉＮＯＳ）表达的影响。方法：选取ＳＤ大鼠制备脑损伤模型。应用免疫组织化学技术和高清晰度彩色病理图像分析系统，对大鼠脑组织神经细胞中ｉＮＯＳ的表达进行了检测。结果：实验性大鼠脑损伤后，大脑局部损伤区及周围神经细胞中有ｉＮＯＳ阳性产物表达明显增强，伤后２ 小时平均积分光密度（ＯＤＩ）较０．５ 小时升高不显著（Ｐ＞ ０．０５），而伤后６、１２ 和２４ 小时ＯＤＩ较０．５ 小时升高非常显著（Ｐ 均＜ ０．０１）；伤前使用Ｌ ＮＡＭＥ则可使ＯＤＩ值下降。脑损伤组与用药组在０．５ 和２ 小时ＯＤＩ值差异不显著（Ｐ均＞ ０．０５），而在６、１２ 和２４ 小时ＯＤＩ值差异非常显著（Ｐ均＜ ０．０１）。结论：Ｌ ＮＡＭＥ对脑损伤后ｉＮＯＳ具有明显的抑制作用，脑损伤后ｉＮＯＳ被大量合成是造成机体一氧化氮升高的直接原因

The effect of N-nitro-L-arginine methy ester on inducible nitric oxide synthase expression in rats with acute cerebral injury

Objective:To assess the effect of NnitroLarginine methy ester(LNAME) on inducible nitric oxide synthase (iNOS) expression in rats with acute cerebral injury.Methods:SD rats were subjected to brain injury,and iNOS expression in nerve cells was determined by immunohistochemical staining and image analysis system.Results:After brain injury,positive iNOS expression was found in local cerebral tissue and nerve cells,but mean optical density was not markedly different at 2 hours compared with 0 5 hour postinjury ( P >0 05).However,mean optical density of iNOS expression was significantly increased at 6,12,and 24 hours compared with 0 5 hour following brain injury (all P <0 01).Pretreatment with LNAME could reduce iNOS expression,and significant differences in mean optical density of iNOS expression were found between treatment and control groups at 6,12,and 24 hours postinjury (all P <0 01).Conclusions:LNAME has inhibitory effect on iNOS expression,and iNOS activation may be related to excessive nitric oxide formation secondary to acute brain injury.