Structure of preantral follicles, oxidative status and developmental competence of in vitro matured oocytes after ovary storage at 4 °C in the domestic cat model

Abstract

BackgroundStorage conditions during transportation of explanted ovaries are a critical step in setting up fertility preservation protocols in both animal and human fields. Here, we evaluated the effects of ovary storage at 4 °C on the preservation of preantral follicles and oocytes retrieved from antral follicles using the domestic cat as model.MethodsOvaries were harvested from fifty-five healthy domestic queens during ovariectomy and stored at 4 °C for 0 (control), 24, 48, 72 and 96 h. In Experiment 1, the effects of the storage period at 4 °C on the morphology, cytoskeleton (α/β tubulin) and DNA integrity (phosphorylation of histone H2AX) of preantral follicles were investigated. In Experiment 2, oocytes recovered from antral follicles were matured and fertilized in vitro to evaluate their meiotic and developmental competence. Reactive oxygen species (ROS), glutathione (GSH) and lipid peroxidation were measured in matured oocytes.ResultsThe results showed that: a) storage up to 24 h did not affect the morphology and the DNA integrity of preantral follicles; b) extended storage times caused progressive morphological abnormalities, disassembling of microtubules and DNA damage; c) storage up to 48 h did not influence in vitro meiotic maturation of oocytes nor cleavage after in vitro fertilization. However, only oocytes stored within the ovary for 24 h produced blastocysts in a percentage similar to control oocytes; d) GSH levels of in vitro matured oocytes did not change at any time during ovary storage; a progressive increase in ROS levels was detected from 48 h associated with elevated lipid peroxidation at 72 and 96 h of storage.ConclusionsStorage of cat ovaries for up to 24 h caused minimal alteration of preantral follicles and oocytes. The extension of the storage period beyond 24 h progressively impaired the structure of follicles, and modified the oxidative status of in vitro matured oocytes and their developmental competence after in vitro fertilization. This information may help when setting up programs for fertility conservation, especially for wild feline species which die in geographic areas located far away from ARTs centers.

Ovarian tissue transportation: a systematic review

“…Only one (Naoi et al 2007) reported higher rates of meiosis resumption when storage was done at 4°C. At this temperature, these authors found decreased MII rates after 48 hours of storage (Naoi et al 2007, Evecen et al 2009, Piras et al 2018, but they all agreed that with PBS or saline solution, cat ovarian tissue can be stored for up to 24 hours at 4°C. Use of superoxide dismutase increased the viability of cumulus-oocyte complexes, embryo production and expression of the antiapoptotic gene Bcl-2, while reducing expression of Bax, an apoptosis regulator (Cocchia et al 2015).…”

“…Four studies were conducted in humans (Isachenko et al 2009, Isachenko et al 2013, Klocke et al 2014, Kyoya et al 2014, six in bovines (Nakao and Nakatsuji 1992, Lucci et al 2004, Matsushita et al 2004, Nagao et al 2010, Wang et al 2011, Vilela et al 2020, seven in cats (Jewgenow et al 1997, Naoi et al 2007, Evecen et al 2010, Cocchia et al 2015, Martins et al 2018, Piras et al 2018, six in goats (Silva et al 2000, Carvalho et al 2001, Santos et al 2002, Chaves et al 2008, Correia et al 2017, six in dogs (Lee et al 2006, Tas et al 2006, Hanna et al 2008, Lopes et al 2009, Evecen et al 2010, Lima et al 2010, five in sheep (Goncalves et al 2015, Barberino et al 2016, Henry et al 2016, Cavalcante et al 2017, Goodarzi et al 2018, five in horses (Love et al 2003, Pedersen et al 2004, Ribeiro et al 2008, Gomes et al 2012, Gastal et al 2017, four in pigs (Wongsrikeao et al 2005, Lucci et al 2007, Tellado et al 2014…”

“…Regarding DNA/RNA analyses, one study applied polymerase chain reaction (PCR) (Cocchia et al 2015) and one evaluated chromatin configuration (Pedersen et al 2004). DNA fragmentation (using TUNEL, ISEL or other techniques) was performed in ten studies (Jewgenow et al 1997, Wongsrikeao et al 2005, Goncalves et al 2015, Kamoshita et al 2016, Cavalcante et al 2017, Gastal et al 2017, Barberino et al 2018, Piras et al 2018, Vilela et al 2020. Four studies used embryo analyses (Wongsrikeao et al 2005, Naoi et al 2007, Ribeiro et al 2008, Wang et al 2011 and five assessed isolated follicles (Lucci et al 2007, Lopes et al 2009, Lima et al 2014, Correia et al 2017, Raffel et al 2020.…”

“…At the time of writing this review, no studies had been completed in humans. IVM of oocytes followed by IVF was performed after transport of bovine (Nakao and Nakatsuji 1992, Matsushita et al 2004, Nagao et al 2010, Barberino et al 2016, feline (Naoi et al 2007, Cocchia et al 2015, Piras et al 2018, ovine (Goodarzi et al 2018) and porcine (Wongsrikeao et al 2005, Tellado et al 2014) ovarian tissue. IVM was also done in four studies in dogs (Lee et al 2006, Tas et al 2006, Hanna et al 2008, Evecen et al 2010, two in horses (Love et al 2003, Ribeiro et al 2008, one in goats (Correia et al 2017) and one in cats (Evecen et al 2009) after ovarian tissue transportation.…”

“…In cats, three studies evaluated oocyte meiotic competence (Naoi et al 2007, Evecen et al 2009, Piras et al 2018. Only one (Naoi et al 2007) reported higher rates of meiosis resumption when storage was done at 4°C.…”