Effect of Aging on Histology and Ultrastructure of Gastric Fundic Gland in Beagle Dogs / 胃肠病学

ABSTRACT

Background:It has been demonstrated that acid secretion-related gastric fundic structures do not degenerate in elderly individuals. As specimens obtained from human body are greatly influenced by environmental factors,the results need to be further verified by standard animals. Aims:To investigate the aging-related changes of histology of gastric fundus and ultrastructure of fundic gland in beagle dogs. Methods:Nineteen healthy beagle dogs were divided into three age groups,8 in younger group(aged 1-5 years),5 in junior elderly group(aged 6-8 years)and 6 in senior elderly group (aged ≥9 years). Gastric specimens obtained from the fundus were examined by light microscope,the thickness of lamina propria and percentage of parenchymal area of fundic gland in lamina propria were measured,and the parietal cells,chief cells and endocrine cells were counted. Ultrastructure of fundic gland cells were observed by electron microscopy,and the area percentages of related organelles were calculated. Results:The thickness of lamina propria in gastric fundus of beagle dogs showed a decline tendency with aging,but no significant differences were found among the three age groups(P >0. 05);in senior elderly group,a marked decrease in density of fundic gland was observed and with an increase of interstitial tissues. The amount of parietal cells and the area percentages of mitochondria and tubulovesicle in parietal cells showed no aging-related reduction(P > 0. 05),while the amount of chief cells,area percentages of zymogen granule in chief cells,and mucous granule in mucous neck cells were significantly decreased in senior elderly group(P < 0. 05). The amount of endocrine cells increased gradually with aging(P < 0. 05). Conclusions:Aging-related degeneration is not existed in acid secretion-related parietal cells and organelles in gastric fundus of beagle dogs. Furthermore,endocrine cells which secret histamine,gastrin,and somatostatin,etc. for stimulating acid secretion even increased. These changes might be a compensatory mechanism for acid secretion in elderly individuals.