During corpus luteum formation, impressive biological events take place to guarantee the transition from original follicular to luteal cells and to support required massive angiogenesis. It has been demonstrated that these phenomena resemble those essential for wound healing. After ovulation, blood vessels release their content in the antral cavity and coagulation takes place. Involvement of platelets in corpus luteum growth has been hypothesized both in human and in rat. On this basis, using platelet lysate (PL), a blood derivative with a higher platelet concentration, we aimed to assess a potential involvement of platelets in swine granulosa cell luteinization and on new blood vessel growth. Our results demonstrate, for the first time in the swine, that platelets could be directly involved in granulosa cell physiological luteinization, since the treatment with PL shifted steroid production from estradiol 17β to progesterone. Moreover, PL stimulated angiogenesis. Nitric oxide could be involved in these effects. These results are important to clarify complex intrafollicular molecular machinery. A better understanding of these mechanisms can be useful to develop more focused therapeutic strategies to contrast sow infertility. In addition, since the pig represents a model for translational studies, collected data could be of interest for human medicine because reproductive pathologies such as Polycystic Ovary Syndrome (PCOS) and endometriosis are often accompanied by platelet dysfunctions.
Keywords: Angiogenesis bioassay; Estrogen; Nitric oxide; Ovarian follicle; Progesterone.
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