Immunofluorescence localization of cannabinoid receptor type 2 in the ileum of juvenile and adult chickens (gallus domesticus) and its association with gga-mir-200a-3p and oxidative stress

While Cannabinoid Receptor Type 2 (CB2R) is known to influence mammalian gastrointestinal function, its distribution in avian guts and associations with gga-miR-200a-3p and oxidative stress remain understudied. This study aimed to immunohistochemically map the cellular distribution of CB2R in the ileum of healthy chickens and to explore its correlation with gga-miR-200a-3p expression. Ileal samples were collected from 32 male and female chickens. The tissues were analyzed to evaluate the localization and expression of CB2R and gga-miR-200a-3p. The findings revealed an age-related difference in the distribution of CB2R throughout the ileum. In the juvenile epithelial cells, components of the lamina propria, enteric neuronal plexus, ileal crypts, smooth muscle cells of the tunica muscularis, and serosal cells exhibited predominantly intense immunoreactivity for CB2R, in contrast to the older age group. While significant differences were observed between juveniles and adults, with higher distribution levels in juveniles, no significant differences were noted between males and females regarding CB2R distribution. Furthermore, in both age and gender groups, the CB2R levels correlated negatively with gga-miR-200a-3p and malondialdehyde, and positively with total antioxidant capacity levels. This study indicates that CB2R is strategically positioned to influence intestinal motility and immune functions, and is associated with gga-miR-200a-3p expression and markers of oxidative stress.