Morphological studies and immunolabeling of female hormonal receptors in Thai swamp buffalo oviducts at prepuberty.

The present study aimed to examine the general morphology of Thai swamp buffalo's oviducts by light microscopy (LM) and scanning electron microscopy (SEM) as well as the expression of estrogen receptor alpha (ER alpha) and progesterone receptor isoform B (PRB) by immunohistochemical technique at the prepubertal stage. The samples composed of the uterotubal junction (UTJ), isthmus, ampulla and infundibulum of prepubertal Thai swamp buffalo oviducts (n=6) were collected from a local slaughterhouse. The results showed that the epithelium of prepubertal Thai swamp buffalo oviducts was composed of ciliated and secretory cells but the feature of nuclear/cytoplasmic protrusions of secretory cells was prominent only in the ampullar and infundibular epithelia. In the UTJ and isthmus, the intensity of PAS staining was reasonably depicted in the secretory cells and the epithelial cell height increased significantly (p<0.05) compared to other segments. The distribution of intraepithelial immune cells was demonstrated to be higher (p<0.05) in the infundibulum and ampulla than the UTJ and isthmus. The SEM micrographs confirmed the differences between the secretory and ciliated cells as well as the characteristics of the nuclear/cytoplasmic protrusions. The intensity of ER and PR nuclear immunolabeling was stained more significantly (p<0.05) in the epithelial cells of the UTJ and isthmus than those of the ampulla and infundibulum. In conclusion, the general histological, SEM and immunolabeling of ER and PR results indicated that there are regional differences to be found in prepubertal Thai swamp buffalo oviducts, i.e. the UTJ and isthmus differing from the ampulla and infundibulum. Indeed, the structures and functional physiology of oviductal epithelial cells might rapidly change for reproduction processes when the ovaries reach to estrous cycle.