Invited review
Potential roles of poly (ADP-ribose) polymerase in male reproduction

Poly (ADP-ribose) polymerase (PARP) is an abundant nuclear enzyme involved in DNA repair and transcriptional regulation. It is now recognized as a key regulator of cell survival and cell death in response to noxious stimuli. Poly (ADP-ribose) polymerase becomes activated in response to oxidative DNA damage and depletes cellular energy pools, leading to cellular dysfunction in various tissues. Poly (ADP-ribose) polymerase over-activation depletes its substrate nicontinamide adenine dinucleotide, slowing the rate of glycolysis, electron transport and adenosine triphosphate formation. Eventually this leads to functional impairment or cell death, as well as upregulation of various pro-inflammatory pathways. Therefore, novel antioxidants and PARP inhibitors have entered clinical development as experimental therapies for various diseases and possibly defective spermatogenesis. This review focuses on the data available on the pathophysiological relevance of the PARP in various stages of spermatogenesis ranging from testicular to ejaculated spermatozoa.