Abstract: To elucidate compositional changes of the brain regions with aging, the authors investigated age-related changes of elements in the corpus callosum, anterior commissure, and fornix of white matter and the pineal body, olfactory bulb and tract, mammillary body, hippocampus, and dentate gyrus of gray matter by direct chemical analysis. In addition, the authors investigated whether there were gender differences in the element contents in their brain regions or not.
After ordinary dissections at Nara Medical University were finished, the corpora callosa, anterior commissures, fornices, pineal bodies, olfactory bulbs and tracts, mammillary bodies, hippocampi, and dentate gyri were resected from the cerebra cut at median line. The brain samples were treated with 99.5% ethanol three times to remove lipids. After ashing with nitric acid and with perchloric acid, the seven element contents of Ca, P, S, Mg, Zn, Fe, and Na were determined by inductively coupled plasma-atomic emission spectrometry (ICPS-7510; Shimadzu, Kyoto, Japan).
With regard to age-related changes of elements, it was found that the Ca and Mg contents increased significantly in the hippocampi with aging; the Ca content increased significantly in the mammillary bodies with aging; the P and Na contents increased significantly in the dentate gyri with aging; and the Mg content increased significantly in the fornices with aging. However, the seven element contents did not change significantly in the corpora callosa, anterior commissures, pineal bodies, and olfactory bulbs and tracts with aging.
Regarding the gender differences in the element contents, it was found that the Zn content was significantly higher in the anterior commissures of men than in those of women. In the olfactory bulbs and tracts, it was found that the Ca, P, and Zn contents were significantly higher in men than in women. In contrast, it was found that the S content was significantly higher in the dentate gyri of women than in those of men. However, no gender differences were found in the hippocampus, mammillary bodies, and fornices.