Effects of long-term in vitro exposure to phosphodiesterase type-3 inhibitors on follicle and oocyte development

Abstract

Germinal vesicle (GV)-stage oocytes retrieved from antral follicles undergo nuclear maturation in vitro, which typically occurs prior to cytoplasmic maturation. Short-term culture with meiotic inhibitors has been applied to arrest oocytes at the GV stage aiming to synchronize nuclear and ooplasmic maturity. However, the results obtained are still far from the in vivo situation. In order to acquire competence, immature oocytes may require meiotic arrest in vitro for a more extended period. The phosphodiesterase type 3-inhibitor (PDE3-I) is a potent meiotic arrester. The effects of a prolonged culture with PDE3-I on oocyte quality prior to and after reversal from the inhibition are not known. This study tested the impact of long-term in vitro exposure of two PDE3-Is, org9935 and cilostamide, on oocytes using a mouse follicle culture model. The results showed that PDE3-I (maximum of 10 mM) during a 12-day culture of follicle-enclosed oocytes did not alter somatic cell proliferation, differentiation or follicle survival. In addition, the steroid production profile was not significantly modified by a 12-day exposure to PDE3-I. The recombinant human chorionic gonadotrophin/recombinant human epidermal growth factor stimulus induced a characteristic normal progesterone peak of luteinization and normal mucification of the cumulus cells, while the enclosed oocyte remained blocked at the GV stage. In vitro maturation of denuded or cumulus-enclosed oocytes derived from org9935-or cilostamide-exposed follicles progressed through meiosis and formed morphologically normal meiotic spindles with chromosomes properly aligned at the equator. In conclusion, long-term culture with PDE3-I was harmless to somatic cell function, differentiation, oocyte growth and maturation. Our results suggested that PDE3-I can be applied when extended oocyte culture is required to improve ooplasmic maturation.

Duration of fertility after fresh and frozen ovary transplantation

“…But what can be done with frozen ovarian tissue of the leukemia survivor if there happen to have been leukemic cells in that tissue? Culturing that tissue to obtain mature follicles for IVF in these patients is currently the subject of intense research efforts (61)(62)(63). Culturing of primordial follicles may still be a distant goal (64)(65)(66)(67)(68), but progress is now being made with threedimensional culturing of secondary follicles, because one mechanism controlling follicle maturation in the ovarian cortex may be physical pressure and tissue rigidity (69)(70)(71)(72).…”

Isolation of Ovarian Components Essential for Growth and Development of Mammalian Oocytes <i>In Vitro</i>

“…Similarly, a high concentration of hypoxanthine promoted the survival and growth of oocyte-granulosa cell complexes in mice [70], pigs [51], and cattle [25,27]. Other phosphodiesterase inhibitors such as 3-isobutyl-1-methylxanthine [2], org9935, and cilostamide [71] have also been used for long-term culture of mouse preantral follicles. Moreover, mouse granulosa cells require cAMP-dependent pathways to maintain meiotic arrest of oocytes after the acquisition of meiotic competence in vitro [66].…”

Phospho-Signaling at Oocyte Maturation and Fertilization: Set Up for Embryogenesis and Beyond Part II. Kinase Regulators and Substrates

“…The PDE3A activity in the regulation of oocyte maturation of several species has been studied extensively e.g. in rodent (Wiersma et al 1998), rat (Richard et al 2001), mouse (Masciarelli et al 2004;Nogueira et al 2003b;Nogueira et al 2005), monkey , porcine (Sasseville et al 2006;Sasseville et al 2007), bovine (Mayes and Sirard 2002;Thomas et al 2002), and human (Nogueira et al 2003a). Various PDE3 inhibitors were used like org9935, cilostamide, or milrinone.…”