The Thai Journal of Veterinary Medicine


Fas ligand (FasL) and its receptor (Fas) are tumor necrosis factor (TNF) members which are involved in theimmune privileged organs, such as the cornea, testis and placenta, by triggering apoptosis in various cell types. Theappearance of a Fas-FasL system might specify the immune privileged status of the buffalo oviduct wherespermatozoa avoid eradication by female immune cells. The objective of this study was to scrutinize the FasL and Fasproteins by immunohistochemistry, FasL mRNA by RT-PCR and the apoptotic degrees by TUNEL analysis in theuterotubal junction (UTJ), isthmus, ampulla and infundibulum of swamp buffalo oviducts at follicular (n=5) and midluteal(n=5) phases. The Fas localization was scattered along the lining epithelium of all oviductal portions at bothestrous cycle stages, whereas the intensity of FasL immunostaining was more noticeable in the epithelial cells of UTJand isthmus at follicular phase and showed significant differences (p<0.05) compared to other segments and to themid-luteal phase. FasL mRNA expression was detected in the epithelial cells of all oviductal segments and the intenseof expression in UTJ and isthmus at follicular phase was greater than similar regions at mid-luteal phase and othersegments. However, the TUNEL-apoptotic cells were rarely detected in all oviductal segments of swamp buffalo atboth phases. The present results indicate that the appearance of Fas and FasL in the UTJ and isthmus which are thesite of sperm reservoir, at follicular phase can be involved in Fas-FasL system that mediate the survival ofspermatozoa and supports the immune privilege status in the swamp buffalo oviduct.



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