[Effects of leptin on development of mouse preimplantation embryos in vitro].

Objective: To investigate the effects of leptin on development of mouse preimplantation embryos in vitro.
Methods: (1) Groups of 2-cell stage embryos randomly selected were placed in drops of CZB medium with or without recombinant leptin (10, 50, 100 and 500 ng/ml) and were cultured to the hatched blastocyst stage, and then embryo-transfer was carried out and the implantation rate was observed and determined. (2) Groups of 2-cell stage embryos randomly selected were placed in drops of leptin free CZB medium and cultured to morula stage. Then we changed the medium, randomized the embryos into CZB medium with or without recombinant leptin (10, 50, 100 and 500 ng/ml), and cultured them to the hatched blastocyst stage.
Results: Addition of leptin to embryo culture media promoted the development from 2-cell stage embryo to morula, blastocyst and hatched blastocyst and improved the implantation rate. Leptin at 0, 10, 50 ng/ml concentrations caused a dose-dependent promotion, nevertheless Leptin at even higher concentrations (100 and 500 ng/ml) only brought on the same promotion as what the Leptin at concentration of 50 ng/ml did (P>0.05). Addition of leptin to embryo culture media seemed to have no effects on the in vitro development from morula to blastocyst and hatched blastocyst.
Conclusion: Leptin plays an important role in the development of preimplantation embryo. It can promote embryo development and embryo implantation.