Objective The aim of this study was to investigate the differences of the cell ultrastucture of normal mouse hatched blastocysts and their dormant ones cultured in vitro after freezing-thawing, and to explore whether the dor-mant embryos have a better anti-freezing shock property than the normal hatched mouse embryos .Methods By transmis-sion electron microscopy , the ultrastructure of these two types of mouse embryos was observed and analyzed .Results By comparative analysis of their ultrastructure , the results showed that the dormant embryos before freezing are being austerity and with lower energy metabolism at a ‘ground state ’ .After freezing-thawing and culture , their cellular structure seemed to be similar to that of the normal embryos cultured in vitro before freezing.However, after freezing-thawing and culture, the number of mitochondria decreased , the nuclei were loose , and their heterochromatin also increased .Conclusions From the ultrastructural observation , compared with the normal mouse hatched embryos , the cellular state of dormant mouse em-bryos after freezing-thawing is more favorable for material storage and energy metabolism , thus, indicating that they have a better anti-freezing property than normal hatched embryos .

Objective The aim of this study is to explore the changes of expression of integrin αvβ3 in bovine u-terine epithelial cells in vitro induced by estrogen or/and progesterone alone or in combination,and to provide a new refer-ence marker for determining bovine uterine receptivity state. Methods RT-PCR was used to analyze the transcriptional changes of αvβ3 expression in bovine endometrium treated by different concentrations of estrogen,progesterone alone or in combination. Results The expression of integrin αvβ3 reached the highest level when the culture medium was added with progesterone at the concentration of 10 -7mg/mL,and the expression of αv and β3 in the 10 -7mg/mL concentration group was significantly higher than that of the control one(P<0.05). Moreover,the expression of αv was highest in the 10 -10 mg/mL E2group,but the expression of β3 was the lowest in that one. In addition,adding with both estrogen and progester-one,the transcriptional level of integrin αvβ3 was significantly higher than that in the control one. The transcriptional level of αv in the treatment group was significantly higher than that in the control group(P<0.05),but the transcriptional level of β3 in this group was not(P>0.05). Conclusions It can be concluded that integrin αvβ3 can be used as a new poten-tial reference marker gene for detecting the bovine uterine receptive status.