Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerova Str., 5a, Moscow 117485, Russia.
Int J Mol Sci. 2023 Aug 26;24(17):13276. doi: 10.3390/ijms241713276.
Brain aging is associated with a progressive decrease in learning abilities, memory, attention, decision making, and sensory perception. Age-related cognitive disturbances may be related to a decrease in the functional capacities of the hippocampus. This brain region is essential for learning and memory, and the lifelong neurogenesis occurring in the subgranular zone of the dentate gyrus may be a key event mediating the mnemonic functions of the hippocampus. In the present study, we investigated whether age-related changes in hippocampal neurogenesis are associated with learning and memory disturbances. Four- and 24-month-old rats were trained to find a hidden platform in a water maze. Though the older group showed higher latency to search the platform as compared to the younger group, both groups learned the task. However, the density of proliferating (PCNA-positive), differentiating (Dcx-positive), and new neurons (pre-labeled BrdU-positive) was significantly lower in the hippocampus of aged rats as compared to young ones. This inhibition of neurogenesis could be related to increased local production of nitric oxide since the density of neurons expressing neuronal NO-synthase was higher in the aged hippocampus. Thus, we can suggest that an age-related decrease in neurogenesis is not directly associated with place learning in aged rats.
大脑衰老与学习能力、记忆力、注意力、决策能力和感官感知的逐渐下降有关。与年龄相关的认知障碍可能与海马体功能能力下降有关。这个大脑区域对学习和记忆至关重要，而齿状回颗粒下层发生的终身神经发生可能是介导海马体记忆功能的关键事件。在本研究中，我们研究了海马体神经发生的年龄相关性变化是否与学习和记忆障碍有关。4 个月大和 24 个月大的大鼠被训练在水迷宫中寻找隐藏的平台。尽管老年组与年轻组相比，寻找平台的潜伏期更高，但两组都学会了这项任务。然而，与年轻大鼠相比，老年大鼠海马体中增殖（PCNA 阳性）、分化（Dcx 阳性）和新神经元（预先标记的 BrdU 阳性）的密度明显降低。这种神经发生的抑制可能与局部产生的一氧化氮增加有关，因为老年海马体中表达神经元一氧化氮合酶的神经元密度更高。因此，我们可以假设，与年龄相关的神经发生减少与老年大鼠的位置学习没有直接关系。
