Transmission electron microscopical study of the developing colonic epithelia in fetuses and neonates in Korean native goat (Carpus hircus)

한국재래산양 태아 및 신생아의 결장상피 발달에 관한 투과전자현미경적 연구

The morphological development of colonic epithelia in fetuses between 60-. 90-, and 120-days gestation and neonates of Korean native goat were investigated by transmission electron microscopy. In the 60-day-old fetuses, the colonic epithelial cells contained nuclei, nucleoli, mitochondria, free ribosomes, and shoo granular and agranular endoplasmic reticula. The zonula occludens, zonula adherens, desmosomes, short microvilli, and masses of glycogen granules were also obsrved. The goblet cells contained a few secretory granules. In the 90-day-old fetuses, the cell organelles of the colonic epithelial cells were better developed than those in the 60 day old fetuses. Increased number of endoplasmic reticula, digitiform intercellular junctions, mitochondria, and Golgi complexes was observed. The goblet cells contained a lot of secretory granules. In the 120-day-old fetuses, the colonic epithelial cells contained long microvilli and well developed cell organelles. The nuclear cleft and large intercellular space were also appeared. Nunerous fibroblasts were seen in the basement membrane. The number of goblet cells was further observed. In the 120 day old fetuses, all colonic epithelial cells shape simple columnar cells. In newborns, the colonic epithelial cells were covered with extensive microvilli. There were many goblet cells with a lot of secretory granules protruding into the intestinal lumen, and some goblet cells secreted their secretory granules into the lumen. In the 60-and 90-day-old fetuses, the colonic epithelial cells appeared to be either simple columnar or stratified columnar depending on areas.