The effect of the cAMP analogue, dbcAMP, on proliferation and apoptosis of rabbit oviductal cells.

It was previously documented that cyclic AMP (cAMP)-dependent intracellular mechanisms can be involved in control of reproductive processes, and pharmacological regulators of these mechanisms could be practically used to improve rabbit fertility (Sirotkin et al. 2008; Sirotkin et al. 2010a; Chrenek et al. 2012). Changes in fertility could be due to changes in oviductal functions. The aim of our study was to examine the involvement of cAMP-dependent intracellular mechanisms in control of oviductal cell functions, in particular the influence of dbcAMP, a cAMP agonistic analogue, on proliferation and apoptosis of cultured oviductal cells. For this purpose, we compared the expression of markers of proliferation (PCNA, cyclin B1) and apoptosis (bax and bcl-2) in the oviduct epithelial cells isolated from rabbits, whose ovarian and oviductal cycle was induced by gonadotropins alone or in combination with dbcAMP (50 microg/animal) by using immunocytochemistry. It was observed that dbcAMP administration caused an increase in the proportion of cells containing PCNA, but not cyclin B1, bax or bcl-2. Higher expression of PCNA, but not cyclin B1, in the dbcAMP-treated group suggests that the dbcAMP administration can stimulate oviductal cell proliferation, probably promoting transition of cells from G0 to G1 and S-phase of the cell cycle. No influence of dbcAMP administration on regulators and markers of apoptosis (pro-apoptotic - bax and anti-apoptotic - bcl-2) suggests that dbcAMP is probably not involved in the control of apoptosis in rabbit oviduct epithelial cells. The involvement of cAMP-dependent intracellular mechanisms in control of oviduct functions is assumed in this study. This is the first demonstration that dbcAMP can stimulate proliferation of the oviduct epithelial cells without influencing their apoptosis.