¹Dicle University, Faculty of Veterinary Medicine, Department of Anatomy, TR-21280 Diyarbakır - TÜRKİYE
²Dicle University, Faculty of Veterinary Medicine, Department of Histology and Embryology TR-21280 Diyarbakır - TÜRKİYE
³Sırnak University, Idil Vocational Scholl Department of Veterinary, Laboratory Assistant Training and Veterinary Laboratory Services PR, TR-73000 Şırnak - TÜRKİYE
⁴Fırat University, Faculty of Veterinary Medicine, Department of Anatomy, TR-23119 Elazığ - TÜRKİYE DOI : 10.9775/kvfd.2021.26875 Cytokeratins are intermediate fi lament proteins found in epithelial cells. Specifi c cytokeratin expression has been suggested to mark diff erent epithelial cell line and also to associate with mammary stem/progenitor cells. However, a comparative analysis of the expression of cytokaratins in the mammary gland during the late lactation and involution periods was limited. Here, the aim of the present study is to evaluate CK8, CK18 and CK19 expressions of the mammary gland in cows during late lactation and involution periods, immunohistochemically. Th e lobe and lobule structure were prominent in the mammary tissue in the late lactation period, but the amount of connective tissue started to increase, and epithelial cells found on the walls of the alveoli had diff erent appearances based on their secretion status. Th e walls of the ducts were covered by simple columnar epithelial cells during late lactation. CK8 and CK18 showed strong expressions in the epithelial cells of several alveoli and ducts inside the lobes and lobules in the late lactation and involution periods. In both late lactation and involution periods, there was no CK19 expression in the mammary gland tissue. In conclusion, it was demonstrated that CK8 and CK18 were expressed in the alveolar and ductal epithelial cells of the mammary gland in cows in the late lactation and involution periods, but CK19 was not expressed. Th us, our study fi ndings revealed the role of CK8 and CK18 in mammary epithelial diff erentiation and maintenance of the normal mammary epithelial layer. Keywords : Mammary gland, Cytokeratin, Cow, Immunohistochemistry