Effect of Low Oxygen Tension Atmosphere and Maturation Media Supplementation on Nuclear Maturation, Cortical Granules Migration and Sperm Penetration in Swine In Vitro Fertilization

Abstract

The aim of this study was to evaluate the efficiency of low oxygen tension (5% CO(2) , 5% O(2) and 90% N(2) ) on in vitro oocyte maturation using defined media (0.1% polyvinyl alcohol - PVA) or 10% porcine follicular fluid (PFF)-supplemented media. To achieve this goal, oocytes were evaluated regarding cortical granules (GCs) migration, nuclear maturation and sperm penetration. Oocytes were in vitro matured under different conditions: 5% or 20% O(2) atmosphere and 0.1% PVA- or 10% PFF-supplemented media and evaluated at 0 and 44 h of maturation. To evaluate the migration of CGs and nuclear maturation, by confocal microscopy, oocytes were incubated with 100 μg of FITC-PNA/ml and 10 μg/ml of propidium iodide. To address sperm penetration, after maturation, in vitro fertilization for 6 h and in vitro culture for 18 h, zygotes were incubated with 10 mg/ml Hoechst 33342. Pronuclei and polar bodies were quantified using an epifluorescence microscope. Atmosphere conditions did not affect the CGs migration, but media supplementation did. Oocytes matured in 10% PFF media had a higher percentage of CGs in the oocyte periphery than oocytes matured in PVA-supplemented media. However, this fact did not have effect on in vitro sperm penetration levels. No effect of atmosphere conditions and media supplementation was observed on the rates of metaphase II oocytes. Therefore, the use of low oxygen tension in association with PVA maturation media does not improve the in vitro maturation system of porcine oocytes, because its use did not improve nuclear maturation, CGs migration and zygotes monospermic rates.

A new microfluidic concept for successfulin vitroculture of mouse embryos

“…In this work, we assessed the effect of the confinement of the embryos in a close compartment, completely surrounded by PDMS, which is permeable to gas [76][77]. Oxygen tension of 5% for embryo culture has been widely adopted in both animal and clinical human IVF laboratories and considered a more physiological concentration that can boosts blastocyst development with no detectable adverse effects [78][79][80][81][82]. While it is true that the diffusion of oxygen through the PDMS could be modelled and compared to that through mineral oil and media, we did not observed detrimental effects on the embryo development due to a different oxygen dynamic.…”

Oxidative stress in oocyte aging and female reproduction

“…Implantation, pregnancy, and survival rate of human oocyte were significantly higher in the hypoxia (5% O 2 ) group than in the normoxic (20% O 2 ) group, and there were more embryos of good quality for transfer and cryopreservation (Belli et al, 2019). The blastocyst development of fertilized embryos and parthenogenetic embryos was significantly increased under hypoxic conditions (5% O 2 ) compared with normoxic (20% O 2 ) in vitro (Kang et al, 2013; Marques et al, 2012). Therefore, the development of oocytes and early embryos can be encouraged by reducing the oxygen partial pressure to suppress oxidative stress in vitro.…”

Expression pattern of glucose metabolism genes correlate with development rate of buffalo oocytes and embryos in vitro under low oxygen condition

“…Our results indicated that 20 mM glucose at 5 % O 2 was better compared to 5.6 mM glucose for in vitro maturation of buffalo oocytes and development of resultant embryos. However, some studies have failed to demonstrate the beneficial effect of low O 2 on the development of pre-implantation embryos in-vitro [23,29]. The reason for such contradictions could be differences in basic culture systems used by different workers while manipulating the O 2 levels as interplay between culture systems and O 2 concentrations is a crucial factor [30].…”