Sex differences of short-term enriched environment on myelinated nerve fibers in the hippocampal formation of middle-aged rats / 第三军医大学学报

ABSTRACT

Objective To investigate the sex differences of the myelinated nerve fibers in the hippocampal formation of mid-aged standard and enriched rats. Methods Twenty 14-month Sprague-Dawley (SD) rats, 10 female and 10 male rats, were randomly divided into enriched group and standard group. Enriched rats were reared in enriched environment and standard rats were reared in standard environment for 4 months. Then, the total volume of the hippocampal formation and the myelinated nerve fibers in the hippocampus were quantitatively estimated by transmission electron microscopy and stereological methods. Results The total volume and mean diameter of the myelinated nerve fibers in the hippocampal formation of standard female rats were significantly bigger than those of standard male rats (P0.05). The mean diameter of the myelinated nerve fibers in the hippocampal formation of enriched female rats was significantly smaller than that of enriched male rats (P0.05). Conclusion The sex differences of the myelinated nerve fibers in the hippocampal formation of mid-aged standard and enriched rats are significantly different, which indicates the response to the enriched environment in the mid-aged male and female rats is different.