Histological and histomorphometrical changes of different regions of oviduct during follicular and luteal phases of estrus cycle in adult Azarbaijan buffalo

In this study the reproductive organs of adult and apparently healthy female Azarbaijan buffaloes werecollected after slaughter from abattoir. Through observation of the ovaries, the luteal and follicular phases ofeach buffalo were specified. A total number of 36 oviducts at follicular phase and 36 oviducts at luteal phasewere collected and 3 tissue samples were taken from 3 regions of infundibulum, ampulla and isthmus of each oviduct. Sections were stained through the use of H&E, PAS, verhoffe and toluidine blue methods.Histological observations revealed that the oviduct consists of 4 layers of mucosa, submucosa, tunicamuscularis and serosa. The primary and secondary folds decreased both in number and in height frominfundibulum to isthmus. Epithelium of folds was composed of simple columnar, although seemspseudostratified in some areas, and contains ciliated and secretory cells. Histomorphometric examinations of three regions demonstrated that the mean height of primary folds increase and the mean thickness of tunica muscularis decrease at follicular phase. The mean thickness of mucosa-submucosa at follicular phase was slightly similar to luteal phase. More visibility of the ciliated cells and mucosal folds in infundibulum and the increase of their height at follicular phase facilitate the capture of the oocyte; the thick tunica muscularis in isthmus transports sperm cells up; and both require promoting fertilization to occur in ampulla.