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Published on: March 5, 2016
Structural Changes in Large Intestinal Aggregated Lymphoid Follicles in Wistar Rats During Postnatal Ontogeny
1Research Institute of Human Morphology, Russian Academy of Sciences, Moscow, Russia. genebio@mail.ru.
Insights
Aggregated lymphoid follicles in rat large intestines develop postnatally. Their size and number increase with age, particularly in the colon, indicating immune system maturation.
Area of Science:
- Immunology
- Gastrointestinal Biology
- Developmental Biology
Background:
- The large intestine harbors immune tissues crucial for gut health.
- Aggregated lymphoid follicles (ALFs) are key components of gut-associated lymphoid tissue (GALT).
- Understanding ALF development is vital for comprehending immune system maturation.
Purpose of the Study:
- To quantitatively assess the development of aggregated lymphoid follicles in the large intestine of Wistar rats across different age groups.
- To investigate age-related changes in the size and distribution of these lymphoid tissues.
Main Methods:
- Quantitative histological analysis of large intestinal tissue.
- Comparison of aggregated lymphoid follicle morphology and distribution in newborn, prepubertal, adult, and old Wistar rats.
- Statistical analysis of lymphoid patch area and follicle counts.
Main Results:
- No aggregated lymphoid tissue was observed in newborn rats.
- Solitary patches with 7-9 follicles were present in the cecum of prepubertal, adult, and old rats.
- The colon showed increased lymphoid tissue with age, characterized by larger patch areas and more follicles per patch, especially in younger animals.
Conclusions:
- Aggregated lymphoid follicles in the rat large intestine develop significantly after birth.
- Postnatal ontogenesis drives the enlargement and increased density of lymphoid follicles in the colon.
- Age-related differences in lymphoid tissue development are most pronounced in the transition from prepubertal to adult stages.
Abstract:
Quantitative evaluation of aggregated lymphoid follicles in various compartments of the large intestine was carried out in Wistar rats of different age: newborn (3-4 days), prepubertal (20-30 days), adult (2-3 months), and old (16-18 months). No aggregated lymphoid tissue was detected in the large intestinal mucosa of newborn animals. The cecum of prepubertal, adult, and old animals contained solitary patches with 7-9 follicles. Higher percentage of aggregated lymphoid tissue, associated with colonic mucosa, was explained by enlargement of the lymphoid patch area and of the number of solitary lymphoid follicles during the postnatal ontogenesis. The mean area of a patch in the distal part of the colon in prepubertal, adult, and old animals was 3.2, 2.5, and 2.2 times larger than in the medial part of the intestine, the number of follicles per patch was 2.8, 2.8, and 2.5 times higher, respectively. The differences were significant only for the two younger groups.
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