Human granulosa cells express proteins of the paraoxonase family

Free radicals are necessary in female reproduction, but at high concentrations they are associated with reproductive diseases and infertility. To maintain these species in non-harmful stationary concentrations, antioxidants act coordinately in reproductive tissues. Paraoxonases (PONs) are hydrolytic enzymes with a wide range of substrates capable of protecting against lipid peroxidation. Recently, PON1, PON2, and PON3 have been localized in follicular fluid (FF), a fluid that is constituted by components of the blood that freely diffuse through the hematofollicular barrier and by products of the local synthesis of ovarian cells. In this work, we describe for the first time the expression of PON1, PON2, and PON3 proteins at the transcriptional and protein levels in human granulosa cells. The proteins were localized intracellularly by confocal microscopy and quantified by western blot using commercial human recombinant PON proteins as standards. The expression of PONs in these cells indicate that their presence in FF is not exclusively due to simple diffusion from the blood and that these proteins have a role in reproduction.