Molecular pathomechanism of amyotrophic lateral sclerosis

在本研究中，我们证明了17β-雌二醇及其生物活性不活跃的立体异构体17α-雌二醇能预防谷氨酸和一氧化氮诱导的大鼠脊髓原代培养选择性运动神经元死亡。通过与谷胱甘肽联合给药，运动神经元保护所需的雌二醇剂量大大减少。本研究结果表明，雌二醇在体外对脊髓运动神经元的兴奋性毒性损伤具有保护作用，可用于肌萎缩侧索硬化症(ALS)的治疗。此外，我们还研究了环状GMP对体外培养的胚胎大鼠脊髓神经元活性氧自由基(ROS)毒性的影响。用cGMP类似物预处理12-24小时可保护脊髓运动神经元和非运动神经元免受过氧化氢或谷胱甘肽耗竭药BSO的损伤。这种保护作用可被cGMP依赖的蛋白激酶(PKG)抑制剂逆转。有趣的是，当培养细胞暴露于BSO 24小时以允许不可逆转地抑制谷胱甘肽合成时，8BR-cGMP仅保护非运动神经元。我们的结果表明，cGMP可以减轻培养的脊髓神经元的氧化损伤，其机制与谷胱甘肽的合成有关。

In the present study, we demonstrated that 17β-estradiol and its biologically inactive stereoisomer, 17α-estradiol, prevented glutamate- and nitric oxide-induced selective motor neuronal death observed in primary cultures of the rat spinal cord. The dose of estradiols required for motor neuron protection was greatly reduced by co-administration with glutathione. The results of this study shows that estradiol protects spinal motor neurons from excitotoxic insults in vitro, and may have application as a treatment for amyotrophic lateral sclerosis (ALS).We also investigated the effect of cyclic GMP against reactive oxygen species (ROS)-induced toxicity in cultured neurons from embryonic rat spinal cords. Pretreatment with a cGMP analogue for 12-24 hours protected both spinal motor neurons and nonmotor neurons against injury induced by either hydrogen peroxide, or a glutathione depletor, BSO.This protective effect was reversed by coadministration with the cGMP-dependent protein kinase (PKG) inhibitor. Interestingly, when cultures were exposed to BSO for 24 hours to allow irreversible inhibition of glutathione synthesis, 8br-cGMP protected only nonmotor neurons. Our results indicate that cGMP attenuates oxidative injury to cultured spinal neurons, in a mechanism associated with glutathione synthesis.