神经元型一氧化氮合酶在缺氧缺血新生大鼠脑组织的表达变化及其抑制剂7-NI的脑保护作用

目的　探讨神经元型一氧化氮合酶 (nNOS)及其选择性抑制剂 7 硝基吲唑 (7 NI)在新生大鼠缺氧缺血性脑损伤 (HIBD)中的作用。方法　制备新生大鼠HIBD模型 ,用RT PCR的方法测定HIBD组缺氧开始后 0h、1h、2h、6hnNOSmRNA的表达 ,同对照组相应时点比较。测定HIBD组、7 NI组缺氧开始后 1h、2h、6h、8h以及对照组一氧化氮合酶 (NOS)、一氧化氮 (NO)、丙二醛(MDA)、超氧化物歧化酶 (SOD)的含量并作相应比较 ,另用TUNEL法比较 3组缺氧结束后 2 4h神经细胞凋亡的情况。结果　在缺氧开始后 2h和 6hHIBD组nNOSmRNA表达高于对照组 (P <0 0 5 ) ,且以 6h表达更高 (P <0 0 5 )。HIBD组各时点与对照组比较NOS、NO、MDA值升高 (P <0 0 1) ,SOD值下降 (P <0 0 1) ,而 7 NI组各时点MDA、NOS和NO值较HIBD组下降 (P <0 0 5 ) ,SOD值升高 (P <0 0 5 ) ,1h时点测定值接近对照组水平。对照组未见明显细胞凋亡情况 ,7 NI组比HIBD组凋亡减少 ,差异具有显著性 (P <0 0 0 1)。结论　nNOS参与了新生鼠HIBD的形成 ,其抑制剂 7 NI通过抗氧化和抑制凋亡发挥了神经保护作用。

Expression of neuronal nitric oxide synthase in brain tissue of hypoxic-ischemic neonatal rat and the cerebral protective effect of neuronal nitric oxide synthase inhibitor 7-nitroindazole

Objective To explore the effect of nNOS and its selective inhibitor 7-NI in neonatal rats with hypoxic-ischemic brain damage (HIBD). Methods The model of HIBD in neonatal rat was made and the expression of nNOS mRNA was measured at different time points and compared with the control group. The levels of NOS?NO?MDA?SOD were also assayed at different time points after aderministering 7-NI, and compared with the HIBD group and the control group. In addition, we observed the degree of apoptosis after 24 h of HIBD. Results Expression of nNOS mRNA was higher at 2 h and 6 h after hypoxia than those in the control group ( P <0.05)and reached more at 6 h ( P <0.05). Concentrations of NOS?NO?MDA increased after HIBD, but concentration of SOD decreased ( P <0.01); 7-NI reduced the levels of NOS?NO?MDA, and level of SOD was higher than those in the HIBD group ( P <0.05). There was no apoptosis in the control group, 7-NI could effectively inhibit the degree of apoptosis after HIBD ( P <0.001). Conclusion nNOS has an important role in the pathogenesis of neonatal rats with HIBD , its specific inhibitor 7-NI can protect brains from hypoxic-ischemic damage through anti-oxidation and prohibiting apoptosis.