Leptin Enhances Maturation and Development of Calf Oocytes In vitro

Contents We investigated the effects of leptin on the in vitro maturation (IVM) and development of calf oocytes. Cumulusoocyte complexes were matured in IVM medium containing 0100 ng/ml leptin. Experiment 1 showed that exposure of calf oocytes to IVM medium containing 1 or 10 ng/ml leptin significantly increased rates of development to the metaphase II stage compared with the control (81.7 +/- 3.0% and 83.3 +/- 2.1% for 1 and 10 ng/ml leptin, respectively, vs 64.1 +/- 5.1% for control; p < 0.05). Experiment 2 showed that 1 or 10 ng/ml leptin significantly improved cleavage rates after in vitro fertilization when compared to control (58.6 +/- 3.3% and 59.3 +/- 2.9% for 1 and 10 ng/ml leptin, respectively, vs 48.5 +/- 2.6% for control; p < 0.05); in addition, when compared to control medium, the addition of 10 ng/ml leptin to the IVM medium resulted in more presumptive zygotes reaching the 4- to 8-cell stage after 48 h of in vitro culture (30.3 +/- 2.3% vs 20.1 +/- 2.3%; p < 0.05) and developing into blastocysts after 8 days of culture (20.4 +/- 1.6% vs 11.7 +/- 1.7%; p < 0.05). Experiment 3 showed that the addition of 1 or 10 ng/ml leptin significantly increased the total number of blastocyst cells on day 8 of culture (114.6 +/- 7.8 and 117.4 +/- 5.9 for 1 and 10 ng/ml leptin, respectively, vs 92.7 +/- 8.3 for control; p < 0.05) and trophectoderm (TE) cells (88.5 +/- 5.5 and 90.6 +/- 3.7 for 1 and 10 ng/ml leptin, respectively, vs 70.1 +/- 5.9 for control; p < 0.05). In summary, these results indicate that the addition of leptin to IVM medium enhances meiotic maturation and embryo development from calf oocytes and improves the quality of embryos derived from these oocytes.