Contribution of iNOS for neurodegeneration in ALS and Parkinson's disease

为了探讨诱导型一氧化氮合酶(INOS)在肌萎缩侧索硬化症(ALS)神经细胞变性中的作用，我们尝试了iNOS基因敲除(iNOS-/-)小鼠与突变型SOD1转基因小鼠(m SOD1Tg/W)杂交。为此，我们从美国杰克逊实验室购买了B6SJL-TGN(SOD1-G93A)1Gur株和B6.129P2-Nos2tm1Lau株。在对每只小鼠的运动功能、寿命和生育力进行3代观察后，将雄性mSOD1TG/W小鼠与雌性iNOS-/-小鼠杂交。将成功建立的雄性mSOD1TG/W II iNOS+/-小鼠与雌性mSOD1W/W II iNOS+/-小鼠进行再杂交。通过这些步骤，我们最终获得了6组不同的小鼠：mSOD1Tg/W II iNOS-/-、mSOD1Tg/W II iNOS+/-、mSOD1Tg/W II iNOS+/+、mSOD1W/W II iNOS-/-、mSOD1W/W II iNOS+/-、mSOD1W/W II iNOS+/+。每组随机抽取8~12只小鼠，严密观察其运动功能，直至每只mSOD1TG/W小鼠不能进食和饮水。观察者对老鼠的基因型别视而不见。通过临床检查、体重、握力和在旋转棒上的停留时间来评估运动功能。MSOD1Tg/WⅡiNOS+/+与mSOD1Tg/WⅡiNOS+/-、mSOD1Tg/WⅡiNOS+/+与mSOD1TG/WⅡiNOS-/-比较差异有统计学意义，后两组运动功能恶化时间明显早于前一组。这些结果提示，iNOS可能在mSOD1TG/W小鼠的神经退变过程中起到保护作用。

To investigate the roles of inducible nitric oxide synthase (iNOS) for neuronal cell degeneration in amyotrophic lateral sclerosis (ALS), we have attempted to cross iNOS knockout (iNOS -/-) mouse with mutant SOD1 transgenic (m SOD1 Tg/W) mouse. For this purpose, we purchased the B6SJL-TgN(SOD1-G93A)1Gur strain and the B6.129P2-Nos2tm1Lau strain from The Jackson Laboratory, USA. After observation of motor functions, life span, and fertility of each mouse for 3 generations, we crossed male mSOD1 Tg/W mice with female iNOS -/- mice. Successfully generated male mSOD1 Tg/W II iNOS +/- mice were re-crossed with female mSOD1 W/W II iNOS +/- mice. Through these procedures we finally obtained genetically different 6 groups of the mice; mSOD1 Tg/W II iNOS -/-, mSOD1 Tg/W II iNOS +/-, mSOD1 Tg/W II iNOS +/+, mSOD1 W/W II iNOS -/-, mSOD1 W/W II iNOS +/-, mSOD1 W/W II iNOS +/+. Eight to 12 mice from each genotype group were randomly selected and their motor functions were closely observed until the day when each mSOD1 Tg/W mouse was unable to eat and drink. The observers were blinded for genotypes of the mice. Motor functions were evaluated by clinical examination, by body weight, and by grasping power and the remaining time on the Rotarod. Significant differences were demonstrated between mSOD1 Tg/W II iNOS +/+ and mSOD1 Tg/W II iNOS +/-, and between mSOD1 Tg/W II iNOS +/+ and mSOD1 Tg/W II iNOS -/-; deterioration of motor function was significantly earlier in the latter 2 groups than the former one. These results imply that iNOS might play protective roles in processes of neurodegeneration in m SOD1 Tg/W mouse.