Materials and Methods: We used 20 ileal samples from fetal sheep whose gestational ages range from 63 to 147 days. To visualize CB2 expression in ileum, we applied labeled Streptavidin Biotin method to paraffin sections.

Results: The majority of the intestinal epithelium showed a weak positive reaction for CB2. Interestingly, we observed intense intracytoplasmic staining in some epithelial cells of both intestinal villi and crypts. Moreover, CB2 immunoreaction was observed in ganglion cells in submucosal and myenteric plexus. We also determined positive staining in smooth muscle cells of lamina and tunica muscularis. Towards the end of the prenatal period, we found histologically mature Peyer’s patches. CB2 staining was detected in the majority of immune cells forming the follicle and dome region. Follicle associated epithelium also showed CB2 immunoreaction.

Conclusion: The present study is the first to describe CB2 expression in fetal sheep ileum. CB2 expression was determined in epithelial cells, smooth muscles, enteric neurons and Peyer’s patches in ileum fetal sheep under physiological conditions. Considering the morphology of epithelial cells with intense CB2 staining and previous findings, CB2 may be a possible marker for enteroendocrine cells during the prenatal period.