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Todd Glover

Improved In Vitro Oocyte Maturation For Feline Assisted Reproductive Technologies

Todd Glover and Charles R. Long

Department of Physiology and Pharmacology, Texas A&M University, College Station, TX

Todd Glover

Objective – Feline cloning is a valuable assisted reproductive technology (ART). Cloning can help preserve superior or unique animals and endangered species.  Increased cloning efficiency along with genetic engineering could be used to create biomedical models for animal and human research.  Improving the percentage of oocytes that mature to the metaphase II stage of meiosis could improve cloning and other ARTs.

Procedure – This experiment examined different strategies to increase the developmental competencies of feline oocytes.  In 3 replicates, Experiment 1 compared additives to the standard feline maturation media (MAT) oocytes were cultured for 24 hours in MAT with or without added 100 mM Cysteamine and 1 µg/ml Estradiol (Cys-E2).   Experiment 2 evaluated oocyte meiotic arrest prior to in vitro maturation. In three replicates, the oocytes were placed MAT (without hormones for 24 hours) containing either 25 nM roscovitine, 1mM dbcAMP or both for 24 h, then washed and matured as usual.  At the end of maturation, all oocytes were fixed and mounted for histological analysis of meiotic progression.

Results – Addition of Cys-E2 in Experiment 1, showed no effect on meiotic progression (67.1 vs. 68.3 %).  Addition of roscovitine alone or in combination with dbcAMP arrested oocytes at the germinal vesicle stage, whereas dbcAMP or no additive did not (90.6, 67.8, 25.0, 14.8%, respectively). More oocytes resumed meiotic maturation when arrested prior to maturation (86.9, 75.4, 87.0, and 65.0 for Combined, dbcAMP, roscovitine and non-arrested groups, respectively).

Conclusions and Clinical Relevance – Thus, oocyte meiotic arrest prior to in vitro maturation of cat oocytes not only improves maturation rates, it allows improved utilization of resources and scheduling of ART procedures.