Porcine follicular fluid derived from > 8 mm sized follicles improves oocyte maturation and embryo development duringin vitromaturation of pigs

Abstract

Summary The aim of the present study was to investigate the effects of porcine follicular fluid (pFF) from large-sized (LFF; >8 mm in diameter) and medium-sized (MFF; 3–6 mm in diameter) follicles on the maturation and developmental competence of porcine oocytes. Cumulus–oocyte complexes (COCs) were collected from follicles 3–6 mm in diameter. The collected COCs were incubated for 22 h with LFF or MFF (in vitro maturation (IVM)-I stage) and were incubated subsequently for 22 h with LFF or MFF (IVM-II stage). Cumulus expansion was confirmed after the IVM-I stage and nuclear maturation was evaluated after the IVM-II stage. Intracellular glutathione (GSH) and reactive oxygen species (ROS) levels were measured and embryonic development was evaluated. Relative cumulus expansion and GSH levels were higher in the LFF group compared with in the MFF group after the IVM-I stage (P < 0.05). After the IVM-II stage, the numbers of oocytes in metaphase-II were increased in the LFF group and GSH content was higher in all of the LFF treatment groups compared with in the MFF treatment groups during both IVM stages (P < 0.05). ROS levels were reduced by LFF treatment regardless of IVM stage (P < 0.05). Blastocyst formation and the total numbers of cells in blastocysts were increased in all LFF treatment groups compared with the control group (P < 0.05). These results suggested that pFF from large follicles at the IVM stage could improve nucleic and cytoplasmic maturation status and further embryonic development through reducing ROS levels and enhancing responsiveness to gonadotropins.

In vitro maturation using αMEM with reduced NaCl enhances maturation and developmental competence of pig oocytes after somatic cell nuclear transfer

“…Previous reports indicate that addition of PFF to IVM medium effectively inhibits polyspermy after IVF [ 32 ] and contributes to improving the normal monospermic fertilization [ 33 ]. In another study, oocytes matured in a medium containing PFF showed enhanced embryonic development [ 34 ]. Generally, PFF is aspirated from the antral follicles, and the composition of PFF differs depending on the size of follicles [ 35 ].…”

Alpha-linolenic acid enhances maturation and developmental competence via regulation of glutathione, cAMP and fatty acid accumulation during in vitro maturation of porcine oocytes

“…To evaluate effect of ALA on cumulus expansion, twenty to thirty COCs in each group were used to assess cumulus expansion at 22 h after IVM. Image J software (version 1.46; National Institutes of Health, Bethesda, MD, USA) was used to measure the area of each COCs, and all of cumulus expansion data were normalized to non-ALA group at 0 h (Park et al, 2020). Fulka, 1976;Park et al, 2020).…”

“…The cumulus cells were denuded by gently pipetting in maturation medium containing 0.1% (w/v) hyaluronidase and denuded oocytes were fixed in 4% (v/v) paraformaldehyde solution at room temperature for 7 min. Then, they were stained with 5 μM CellTracker TM for 30 min in a dark room (Park et al, 2020). Stained oocytes were washed three times with PBS-PVA and were observed under an epifluorescence microscope with optical filter (ex: 510-560 nm, em: 590 nm).…”

“…Fifty putative zygotes were placed in 4-well plates with 500 μL of porcine zygote medium-3 (PZM-3) supplemented with 0.3% (w/v) BSA and cultured for 48 h at 38.5℃ in 5% CO 2 . Then, the culture medium was changed for fresh medium and the putative zygotes were incubated for 5 days (Park et al, 2020). Cleavage rate and blastocyst formation were evaluated at 48 and 168 h after insemination.…”

Impact of preovulatory follicle maturity on oocyte metabolism and embryo development

“…Physiological maturity of the preovulatory follicle, indicating its readiness nurture the maturing oocyte, is positively associated with circulating estradiol concentration and follicle size ( 11 ). In cattle ( 11–13 ), humans ( 14 ), and swine ( 15 , 16 ) the maturity of the preovulatory follicle at the time of a gonadotropin releasing hormone (GnRH)-induced LH surge affects establishment and maintenance of pregnancy. Increased preovulatory follicle diameter and higher levels of circulating estradiol at GnRH administration were associated with improved embryo quality and increased overall embryo cleavage and blastocyst development rates ( 12 , 13 ).…”