In vitro maturation and degeneration of domestic cat oocytes collected from ovaries stored at various temperatures

Abstract

Cat oocytes have the unique ability to mature in vitro after temporary storage at 4°C which can provide opportunities to rescue oocytes from the ovaries of endangered felids after sudden death or medical ovariohysterectomy. It has been demonstrated that factors such as season, culture conditions and morphological quality of oocytes influence the meiotic competence of domestic cat oocytes. In the present study we determined the meiotic maturation rate and incidence of apoptosis or necrosis in domestic cat oocytes collected from ovaries stored at different temperatures. Nuclear status and the presence of the first polar body were evaluated by fluorescence DAPI staining. Cell death was detected using Annexin-V, a phospholipid-binding protein that detects translocation of phosphatidyl-serine to the outer cytoplasmic membrane. Most oocytes (77.5%) collected from ovaries immediately after ovariohysterectomy (control group) resumed meiosis and reached metaphase II. A similarly high percentage of oocytes underwent nuclear maturation after recovery from ovaries stored for 6 h at 4°C (68.6%) or at room temperature (55.5%), but the rate of maturation after recovery from ovaries stored for 24 h at 4°C was greatly reduced (15.3%) Not surprisingly, the highest percentage of apoptotic oocytes were seen in Group 3, and the lowest frequency of apoptotic oocytes were observed in Group 1. Correspondingly, Group 1 had the highest percentage of necrotic oocytes. Thus, our results indicate that storage of domestic cat ovaries at room temperature, even for a short time, can negatively influence the competence of oocytes to undergo nuclear maturation in vitro.

The seasonal and ovarian status effects on in vitro production of domestic cat embryos between Equator and Tropic of Capricorn

“…However, only oocytes stored within the ovary for 24 h produced blastocysts, indicating that the ability to achieve nuclear maturation is an inadequate indicator of fertilization and developmental competence. Data obtained by Wlodarczyk et al (2009) indicated that storage of domestic cat ovaries at room temperature, even for a short time, can negatively influence the compe- tence of oocytes to undergo nuclear maturation. Freisted et al observed that after IVM/IVF, cleavage rates were significantly higher (P<0.05) during breeding season than during non-breeding season.…”

Total Cell Number and its Allocation to Trophectoderm and Inner Cell Mass in In Vitro Obtained Cats' Blastocysts

“…It was only hypothesized that cytoplasmic immaturity of oocytes, chromosomal abnormalities in blastomeres and suboptimal culture conditions could cause longer intermitotic periods and, consequently, slower embryo development (Wlodarczyk et al. ; Kovacic and Vlaisavljevic ).…”

Efecto de Temperatura y Tiempo de Almacenamiento de Ovarios de Alpacas sobre la Tasa de Maduración y División in vitro de Ovocitos

“…Esta situación se asemeja a otros estudios donde se reportaron bajas tasas de división y formación de blastocistos cuando los ovarios fueron guardados a 4 °C (Yang et al, 1990) o 10 °C (Shigeki y Yasuo, 1993, citado porWani y Nowshari, 2005). Esto puede ser posible debido a que la membrana lipídica de los ovocitos bovinos sufría cambios cuando se exponía a temperaturas inferiores a 20 °C (Arav et al, 1996); así como lesiones del huso meiótico y endurecimiento de la zona pelúcida que afectaba directamente la fecundación (Wlodarczyk et al, 2009). Sin embargo, la fase de transición lipídica no ha sido examinada para los ovocitos de alpaca.…”