Aging-related dopaminergic neuronal loss and its motor phenotypes are well known. Excessive loss of dopaminergic neurons leads to Parkinson's disease (PD), the most common neurodegenerative disorder characterized by the loss of nigrostriatal dopamine-producing neurons. In mice, however, aging-related dopaminergic neuronal loss and its consequences for motor function are poorly understood. We observed the phenotype of wild-type C57BL/6 mice over an extended period of time. C57BL/6 mice exhibited age-dependent locomotor impairments, including hindlimb defects and the number of dopaminergic neurons decreased in aged mice, contributing to locomotor dysfunction. We observed a reduction in striatal dopamine levels in aged mice using high-performance liquid chromatography (HPLC). Thus, dopamine levels are affected by the loss of dopaminergic neurons. Furthermore, fragmented mitochondria were observed in dopaminergic neurons of aged mice but not in those of young mice. Aging-related dopaminergic neuronal loss and accumulation of damaged mitochondria may underlie the pathophysiology of aging.

中文翻译：

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C57BL / 6小鼠中与衰老相关的运动功能和多巴胺能神经元丢失。

衰老相关的多巴胺能神经元丢失及其运动表型是众所周知的。多巴胺能神经元的过度丧失会导致帕金森氏病（PD），这是最常见的神经退行性疾病，其特征是产生黑纹状体多巴胺的神经元的丧失。然而，在小鼠中，与衰老相关的多巴胺能神经元损失及其对运动功能的后果知之甚少。我们在延长的时间内观察到了野生型C57BL / 6小鼠的表型。C57BL / 6小鼠表现出年龄依赖性的运动功能障碍，包括后肢缺陷，并且老年小鼠的多巴胺能神经元数量减少，从而导致运动功能障碍。我们观察到使用高效液相色谱（HPLC）的老年小鼠纹状体多巴胺水平降低。因此，多巴胺水平受多巴胺能神经元损失的影响。此外，在老年小鼠的多巴胺能神经元中观察到线粒体破碎，而在年轻小鼠中则没有。与衰老相关的多巴胺能神经元丢失和线粒体受损可能是衰老的病理生理基础。