Expression and Localization of Aquaporin-1 Along the Intestine of Colostrum Suckling Buffalo Calves.

Aquaporin-1 (AQP1), a six-transmembrane domain protein, belongs to a highly conserved group of proteins called aquaporins known to regulate permeability across cell membranes. Although the role of AQP1 has been extensively studied, its specific activity along the gastrointestinal tract in animals during early postnatal development is poorly known. This study investigates the expression of AQP1 mRNA and protein in the small and large intestine of water buffalo calves after colostrum ingestion using reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and cellular localization of AQP1 by immunohistochemistry. Our results revealed AQP1 immunoreactivity and the presence of the corresponding mRNA in all the examined tracts of the intestine but with a different cellular localization. Western blotting confirmed the presence of AQP1, with a more intense band in colostrum-suckling animals. These findings offer insights into AQP1 expression in the small and large intestine, suggesting its involvement in osmoregulation in gastrointestinal physiology particularly during the first week after birth in relation to specific maturation of intestinal structures.