Influence of aging on experimental gastrointestinal motility in extraction of rat molar teeth

The purpose of the present study was to determine whether different consistency of diet and malocclusion induced by the extraction of molar teeth on the masticatory organs modulated gastric acid secretion, gastric emptying and intestinal transit in young and elder rats. Male Wistar rats (young, 5 weeks; elder, 1.5 years) were used in this experiment, and were divided into 2 groups. Group one (G1) was maintained with solid diet, Group two (G2) with mud diet. Further, the mandibular molar teeth of G2 were extracted. The experimental period was 10 weeks. The effect of aging and malocclusion on the parameters of gastric secretion was examined using pylorus-ligated rats. The gastric emptying rate (GER) and small intestinal transit rate was determined in rats by evans blue from the stomach and charcoal from the small intestinal, respectively. In pylorus-ligated rats, Young-G2 rat of gastric juice volume, acid output and pepsin secretion remarkably showed significant decrease in comparison with Young-G1 group, but there was not significant difference between Elder-G1 and Elder-G2. GER of Young-G2 rat group was 44.2±7.9%, significantly lower than that of Young-G1 rat group (61.6±8.8%, P<0.01), but Elder-G1 rat group were not significantly different than those of rats of Elder-G2 group. In small intestinal transit rates of charcoal meals, G1 and G2 of young were 73.3±9.1 and 55.1±8.6%, respectively, and Elder groups were 61.7±9.8 and 52.6±7.7%, suggesting an insignificant effect on diet. These results suggest that the diet and malocclusion, induced by extraction of mandibular molar teeth of young rat groups, may have a great influence compared to elder rat groups.