Investigation of Mast Cell Distribution in the Ovine Oviduct During Oestral and Luteal Phases of the Oestrous Cycles

Mast cells are heterogeneous cell populations that play significant roles in many organs and systems and involve various physiological processes. We aimed to evaluate mast cells in the ovine oviduct mucosa by means of their staining and ultrastructural characteristics. The ovine oviduct samples of Akkaraman breed were collected from the slaughterhouse and they are categorized as luteal and oestral phases. They were fixed either with 10% formalin or IFAA and stained with Toluidine blue and Alcian blue and Safranin O (Ab/SO). Mast cells were located near blood vessels and basal membrane. Compared to 10% formalin fixed tissues, the number of mast cells were higher in IFAA fixed tissues (P=0.003). Importantly all mast cells Ab(+) and SO(-) so that they were categorized as mucosal type. The number of mast cells did not differ between luteal and oestral phases (P>0.05). However, there were significant differences among different regions of the oviduct with a less count in the isthmus regions (P=0.006). Transmission electron microscopy revealed that the oviduct mast cells contained two types of granules: an electron lucent, electron dense. Some electron lucent granules contained an eccentrically located crystal-like structure. The significance of less mast cell counts in the isthmus and the eccentrically located single crystal-like structure should be further investigated in future studies.