Small intestinal development in the young chick: crypt formation and enterocyte proliferation and migration

Area of Science:

• Gastroenterology
• Developmental Biology
• Cell Biology

Background:

• The chick small intestinal epithelium undergoes significant development post-hatching.
• Understanding the dynamics of epithelial cell proliferation and migration is crucial for comprehending gut development.

Purpose of the Study:

• To investigate the post-hatch development of the chick small intestinal epithelium.
• To characterize the changes in cell proliferation and crypt morphology during early post-hatch development.

Main Methods:

• Immunostaining using proliferating cell nuclear antigen (PCNA) and 5-bromo-2-deoxyuridine (BrdU) to assess cell proliferation.
• Microscopic examination of jejunal crypts and villi at various time points post-hatch.

Main Results:

• Jejunal crypts were small and single at hatching, rapidly developing branching and increased cell numbers/size within 108 hours.
• Initially, nearly all epithelial cells proliferated; by 108 hours post-hatch, over 80% of proliferation was localized to crypts.
• Villus cell transit time, estimated using BrdU, was 72 hours at 48 hours post-hatch and increased to 96 hours by 336 hours.

Conclusions:

• A rapid transition occurs within 108 hours post-hatch from widespread epithelial cell proliferation to a defined proliferative zone in the jejunal crypts.
• This transition involves the establishment of constant cell division and migration within the crypts, leading to mature intestinal architecture.