Postnatal development study of histomorphometrical structure of small intestine in female Wistar rat

    Quantitative and qualitative analysis of small intestine structure was performed during early postnatal development in female Wistar rats. For this purpose, tissue samples were taken from three segments; duodenum, jejunum and ileum of rats small intestine on birth day and 7, 14, 21, 28, 35, 42, 60 and 90 days of age and fixed in formal saline10%. For microscopic studies, following routine tissue processing, 5-6µm sections were made and stained with haematoxylin-eosin. The results showed that pronounced histological and histometrical changes occur during physiological growth. Mean number of villi were decreased, but their mean of height increased during maturation in all segments of small intestine. The mean height of villi were greatest in duodenum and decreased in jejunum and ileum, respectively (p<0.05). Number and depth of crypts increased in all segments of small intestine with the age. The thickness of tunica mascularis was increased with age significantly (p<0.05). It was most prominent in duodenum in compare to jejunum and ileum. Primary and secondary lymphoid follicles of the Peyer’s patches in jejunum and ileum were seen clearly at 21 and 28 days old rat, respectively.