Atrial natriuretic peptide is an antiapoptotic factor for human granulosa luteinized cells with impact on the results of COH/IVF in women undergoing IVF program

Aim: To investigate human granulosa luteinized cells as a local source of atrial natriuretic peptide (ANP) and its relationship to cell viability, development of preovulatory follicles and fertilization rate of oocytes. Material and Methods: Indirect immunofluorescent technique, proANP kit, 4'6-Diamidino-2-phenylindole (DAPI)-DNA staining and Caspase-3 activity assay were used to examine localization patterns, concentrations in follicular fluids (FFl) and antiapoptotic role of ANP, respectively. Results: ANP is expressed on granulosa cells with membrane, submembrane and specific granular cytoplasmic localization. Significant differences in the mean concentrations of ANP in FFl and in the mean levels of apoptotic human granulosa luteinized cells (GLC) were found between women with high and low immunoreactive ANP expression (P < 0.05). Concentrations of ANP correlated inversely and significantly with the percentage of apoptotic GLC isolated from the same women (r = -0.2645; P < 0.05). Enhanced in vitro production of ANP by granulosa cells (after sodium nitroproside and 2Bu-cGMP treatment), as well as after treatment with human recombinant ANP was associated with significant suppression of Caspase-3 activity compared to control cells (P < 0.05). Concentrations of ANP in FFl correlated positively and significantly with the number of punctured follicles and oocytes retrieved (r = 0.44716, r = 0.57854; P < 0.05) and with the fertilization rate of oocytes in vitro (r = 0.59773; P < 0.05). Conclusion: Human granulosa luteinized cells are a local source of ANP in the preovulatory human follicle, which acts as a survival factor through cGMP signaling, and its levels in follicular fluids are positively associated with the number of punctured follicles, isolated oocytes and their fertilizability in vitro.