Electrophoretic profile of isthmic and ampullary oviductal fluid proteins at luteal and non-luteal stages of estrous cycle in buffaloes

Abstract

This study was undertaken to examine the electrophoretic profile of buffalo oviductal fluid proteins from different regions of the oviduct at different stages of estrous cycle. Oviducts were collected from apparently healthy buffalo genital tracts (nonIuteal and luteal stages ofestrous cycle) and separated into isthmus and ampulla. The total protein and albumin concentrations were assessed in isthmic and ampullary oviductal fluids at non luteal and luteal stages of estrous cycle. To study the electrophoretic profile, each segment of oviduct (nonluteal and luteal) was flushed with PBS (pH 7.4). The flushing obtained were centrifuged (3 000 rpm; 30 min), filtered (0.2/l) and frozen at -20°C. The proteins in pooled nonluteal and luteal oviductal fluids were precipitated overnight using ammonium sulphate, centrifuged (10 000 rpm; 30 min) and dialyzed (> 10kDa). After protein estimation, aIiquots of samples containing 10 mg proteins were lyophilized in cryovials and stored frozen at -20°e. The 'whole oviductal proteins, isthmic and ampullary proteins at nonluteal and luteal stages and follicular proteins were exposed to one dimensional sodium dodecyl sulphate polyacrylamide gel (SDS-PAGE) along with blood serum proteins. Results revealed that the total protein and albumin levels were higher at nonIuteal than the luteal stage of estrous cycle irrespective of region of oviduct. One dimentional SDS-PAGE separation revealed the protein pattern of oviductal fluid to be generally similar to that of blood serum and follicular fluid. However, 4 proteins (95, 43, 29 and 20 kDa) appeared to be oviduct specific. All the 4 proteins were observed in isthmic and ampullary fluid irrespective of stage of estrous cycle. No follicular fluid specific proteins could be observed in this study. This study indicates the existence of oviduct specific proteins in buffalo oviductal fluid besides the transudates from serum.