Abstract
There are only a few reports in the literature, concerning the aging changes of the alimentary canal from the stomach to the colon. For that reason, the author has investigated the histopathological changes of the gastro-intestinal tract of the various age group to elucidate the cytological features which are encountered in aging process. Ninety six fresh autopsy cases with no primary alimentary tract diseases were investigated light microscopically (LM). Besides, materials of the biopsy cases were taken from duodenum and colon by fiberscope, and examined by LM as well as scanning and transmission electron microscopic (EM) studies. Furthermore, a semi-quantitative analysis of DNA in the nuclei of the colonic mucosal epithelium was performed. Moreover, alteration of the intestinal absorption in the rat intestine with aging has been investigated in virtue of the tracers such as fesin and horseradish peroxidase (HRP).
The results were as follows :
1) Atrophy and intestinal metaplasia of the gastric mucosa became much more evident as the aging proceeds. The quantitative determination of the thickeness ratio between the mucosa and muscular layer is performed, revealing the result that the relative decrease of the mucosal thickeness in aging process.
2) The duodenal mucosa revealed gradual morphological evidence for atrophic process with aging.
3) Atrophy of the mucosal and muscular layers of the small intestine and the colon in autopsy materials became evident with aging and also fibrosis of muscular layer increased parallel to aging. Furthermore, in biopsy materials of the colon, increase of granular cells at the bottom of the crypts was observed with aging.
4) Arteriosclerosis usually began over thirty years of age and were observed more commonly and remarkably with aging. Therefore, it was postulated that arteriosclerosis should be responsible for the mucosal atrophy per se.
5) The transmission EM study showed no noticeable change of the mucosal basement membrane of duodenum and colon with aging, except for increasing of collagen fibrils in adjacent areas. The scanning EM study revealed decreased wrinkling pattern of the mucosal villi which was seemed to correspond to mucosal atrophy as seen with the LM examination.
6) The semi-quantitative analysis of DNA in colonic biopsy materials revealed the tendency of decrease in volume upon aging. The capability of DNA synthesis declined with aging in the bottom epithelium of the colonic mucosal pit.
7) There was no obvious differences concerning the absorption of fesin and HRP between young and aged rats, except for suckling stage.
