Objective To investigate the expression and distribution of leptin in pre-implantation embryo,and its effect on mouse embryo development in vitro. Methods Adult NIH female mice were superovulated and then mated with fertile males of the same strain. On the morning of 1st to 4th d of pregnancy,the oviduct and horn of uterus were dissected out and flushed with DMEM/F12 medium adequately. The embryos collected were subjected to the following procedures: ①Total RNA was isolated from embryos of each stage respectively and mRNA expression of leptin was detected by RT-PCR. ②Immunofluorescence staining was performed on blastocysts to analyze the expression and the distribution of leptin protein under laser confocal microscope. ③Eight-cell embryos were cultured in medium containing leptin antibody at various concentrations to observe the formation and hatching of blastocysts. Results ①Leptin mRNA expression was only detected in blastocyst,and no expression was detected in embryos in other stages. Leptin protein was detected in cytoplasma,membrane of trophoblastic cell and inner cell mass,however no expression was detected in cell nucleus. ②Leptin polyclonal antibody significantly inhibited formation of blastocysts (1∶400,P

Comparative,medicine is a branch of laboratory animal seiences which also cuts the first edge of the morden medical sciences.This article mainly discussed the origin of comparative medicine,its contributions to life sciences.relationships between it and laboratory animal science,its importance for life science and medical researches.Most of all.the necessarity and feasibity to teach comparative medicine for the undergraduate students were highlighted