CD-1小鼠海马H3K9三甲基化水平的年龄化改变 及其与认知功能改变的相关性研究

探讨年龄对CD-1小鼠海马组蛋白H3K9三甲基化(H3K9me3)含量的影响及其与空间学习记忆能力改变的相关性。结果发现,18月和12月龄鼠在放射状水迷宫中学习期和记忆期的潜伏期、错误数均高于6月龄鼠(P_s0.05);18月龄鼠学习期及记忆期的错误数还高于12月龄鼠(P_s0.05)。18月龄鼠海马DG和CA1区H3K9me3水平高于12月龄鼠(P_s0.05),12月龄鼠也高于6月龄鼠(P_s0.05)。DG和CA1区H3K9me3相对含量与学习期的潜伏期和错误数以及记忆期错误数呈正相关(P_s0.05),而CA3区H3K9me3相对含量与学习期和记忆期的错误数、潜伏期之间无明显相关性(P_s0.05)。以上结果提示,CD-1小鼠年龄相关空间学习记忆损害可能与海马组蛋白H3K9me3升高有关。

Changes of age-related H3K9 trimethylation in hippocampus and its correlation with cognitive impairment in CD-1 mice

In this study,we explored the effect of age on trimethylation of histone 3 in the lysine 9 site (H3K9me3) and its correlation with the impairment of spatial learning and memory in CD-1 mice.The results showed that the number of errors and latency during learning and memory phases in the radial arm water maze (RAWM) in the mice aged at 18-and 12-month old was significantly longer or more than those in the 6-month old mice (Ps ＜0.05),with more number of errors in the learning and memory phases in the 18-month old mice compared to the 12-month old mice (Ps ＜0.05).A significantly higher level of H3K9me3 in the hippocampal DG and CA1 subregions was found in the 18-month old mice relative to the 12-month old mice (Ps＜0.05),and so did in the 12-month group relative to the 6-month group (Ps ＜0.05).The H3K9me3 levels in the DG and CA1 were positively correlated with the learning errors and latency,and the memory errors in the RAWM (Ps ＜0.05).There was no significant correlation between the performance of RAWM and the levels of H3K9me3 in CA3 (Ps ＞0.05).Our results suggested that the increased hippocampal H3K9me3 might be involved in the age-related impairment of spatial learning and memory in CD-1 mice.