Maturation in vitro of pig oocytes in protein-free culture media: fertilization and subsequent embryo development in vitro

• Published in: Biology of reproduction 1998-05, Vol.58 (5), p.1316-1320
• Main Authors: Abeydeera, L.R, Wang, W, Prather, R.S, Day, B.N
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Blastocyst - physiology; Blastocyst - ultrastructure; Cell Nucleus - physiology; CERDO; CULTIVO DE EMBRIONES; CULTURE D'EMBRYON; CULTURE MEDIA; DESARROLLO EMBRIONARIO; DEVELOPMENTAL COMPETENCE; DEVELOPPEMENT EMBRYONNAIRE; Early stages. Segmentation. Gastrulation. Neurulation; EMBRYO CULTURE; Embryology: invertebrates and vertebrates. Teratology; Embryonic and Fetal Development - physiology; EMBRYONIC DEVELOPMENT; EXPERIMENTACION IN VITRO; EXPERIMENTATION IN VITRO; FECONDATION; FECUNDACION; Female; FERTILIZATION; Fertilization in Vitro; Fundamental and applied biological sciences. Psychology; IN VITRO EXPERIMENTATION; IN VITRO FERTILIZATION; In Vitro Techniques; MADURACION; MATURATION; MEDIO DE CULTIVO; Meiosis - drug effects; MILIEU DE CULTURE; NUCLEAR MATURATION; Oocytes - physiology; Oocytes - ultrastructure; OVA; OVULE; OVULO; PORCIN; Proteins - physiology; SWINE
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod58.5.1316

In the present study, attempts were made to develop a protein-free (PF) in vitro maturation (IVM) system for pig oocytes and to examine subsequent embryo development after in vitro fertilization. In experiment 1, four IVM media were tested: 1) control: North Carolina State University (NCSU) 23+10% porcine follicular fluid; 2) PF-NCSU: NCSU 23+0.1% polyvinyl alcohol (PVA)+1% amino acids; 3) PF-TCM: Tissue culture medium (TCM) 199+PVA; and 4) PF-WM: PF-Waymouth MB 752/1 medium (WM)+PVA. Oocytes were cultured in the respective media containing eCG and hCG (10 IU/ml each) for 20-22 h and then without hormonal supplements for an additional 20-22 h. After culture, the degree of cumulus expansion and frequency of nuclear maturation were determined. Some oocytes were coincubated with frozen-thawed spermatozoa for 5-6 h in modified Tris-buffered medium containing caffeine and BSA. In experiment 2, oocytes were matured in control, PF-TCM, and PF-WM, fertilized in vitro, and cultured for 144 h in NSCU 23+BSA. Fewer (p < 0.01) oocytes reached metaphase II stage in PF-NCSU (45% vs. 80-85%) than in the other media. Oocytes matured in control medium showed the most cumulus expansion, followed by those in PF-TCM and PF-WM; those in PF-NCSU showed very slight expansion. A lower (p < 0.05) penetration rate was obtained for oocytes matured in PF-NCSU than in the control medium (59% vs. 81%). In contrast to those in control (96%) and PF-TCM (93%), oocytes in PF-WM (65%) showed a lower male pronuclear formation. Compared to that in the control, a significantly lower (p < 0.05) cleavage rate was also observed for oocytes matured in PF-WM. Similar proportions of embryos developed to the blastocyst stage when oocytes were matured in control (22%) and PF-TCM (13%). These results indicate that pig oocytes can be successfully matured in a protein-free medium with subsequent development to the blastocyst stage.