Development of small intestines and large intestines in rats and distribution of gastrin cells

Objective: The purpose of this study was to identify the changes within the small and large intestine of rats during their development and to describe the distribution of gastrin cells. Material and Methods: Small and large intestines obtained from the fetuses of 3 Wistar Albino rats for each group on the 14 th, 16th, 18th and 20th days of gestation, as well as from 10 rats on the 2nd, 5th, 11th, 15th, 20th and 30th days of the postnatal period were examined under the light microscope. Results: On the 14th and 16th prenatal days, there was no structural difference between small and large intestine, and the epithelium included 2-3 successive cuboidal epithelial cells. A circular muscle layer could be observed. On the prenatal 18th day, the small intestines manifested a villi consisting of a single layer of prismatic cells, which included goblet and gastrin cells. There were villi-like structures in large intestine as well. After the prenatal 20th day, the length of the villi and the depth of crypts in the small intestine began to increase, and the villi attained the general characteristics seen in adults by postnatal day 15. The villi-like structures observed in large intestine disappeared by postnatal day 11 and were replaced by simple tubular glands. The number of goblet cells in small and large intestine increased with age. Gastrin cells in the small intestine showed a considerable increase in number especially after weaning. Conclusion: As a conclusion, the morphology of small and large intestine was observed to change with increasing age in the prenatal and postnatal periods. The differences between small and large intestine were identifiable during the early postnatal period. Increasing age and nutrition with solid food appear to be instrumental in determining structural differences. Copyright © 2005 by Türkiye Klinikleri