Summary
Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear hormone receptor expressed predominantly in adipose tissue, and it is implicated in energy homeostasis. In this study, by Western blotting and Immunofluorescence techniques, we demonstrated for the first time that pig spermatozoa express the PPARγ. To investigate the functional role of PPARγ in pig sperm, we evaluated its action on different events that characterize the biology of sperm cell as motility, capacitation, viability and acrosome reaction, using 15-deoxy-12,14-prostaglandin J2 (PGJ2) PPARγ-agonist. Responses to PGJ2 treatments on motility, cholesterol efflux and tyrosine phosphorylation were increased and this broadens the roles of PPARγ in the literature, since it also acts to ameliorate sperm functionality. To deepen PPARγ significance in pig sperm we focused its effects on lipid and glucose metabolism. The evaluation of the triglycerides content, lipase and acyl-CoA dehydrogenase as well as G6PDH activities, suggests that PPARγ induces energy expenditure in pig spermatozoa. These data represent a meaningful advance in the field of sperm energy metabolism since this is an intriguing issue at the beginning of the knowledge. Taken together, our results demonstrated for the first time that PPARγ is expressed by pig sperm improving its functionalities such as motility, capacitation, acrosome reaction, survival and metabolism. The use of PPARγ-agonists may be considered a strategy in the procedures of artificial insemination or other biotechnologies, including cryopreservation.