Effect Of Heat Pretreatment On Early Pregnant Mouse

In this experiment, mice were divided into six groups based on heat temperature and exposure time, In control group, mice were housed at 25℃and normal relative humidity(air RH).In a group treated with a acute heat stress , mice were exposed to a ambient temperature of 43℃for 1h with normal relative humidity. In four groups pre-treated with a same mild heat stress including a successive heat-stressed group and three discontiguous heat-stressed groups, mice were exposed to a ambient temperature of 37℃for 1 hour, and then recovered from 0 to 6 hours(0,2,4,6 hours) , immediately exposed to a ambient temperature of 43℃for 1 hour again. Mice with vaginal plug were heat-stressed on day 1 of pregnancy from 8:00 am to 9:00 am by my experimental protocol(coitus was verified by the presence of a vaginal plug),and the same treatment were used for successive 4 days. To study the effect of a mild heat pretreatment on mice during early pregnancy ,we carried out a measurement on rectal temperature, weight loss, embryos'shape , development stage and competence, GSH level, ROS activity and lymphocyte rates in blood, expressed an uncertain protein with a molecular weight of 70kDa.The results showed as follows: 1 Effect of pre-treatment with a maternal mild heat stress on mice exposed to actue heat environment link to recovery time .the optimal time range to achieve a protective reaction is about 4 hours post heating. 2 The GSH level in three discontiguous heat-stressed groups is lower than that in contol group,acute heat-stressed group and successive heat-stressed group,and ROS activity increased distinctively after pre-treatment with a mild heat stress,the difference was significant(p﹤0.05). 3 When the bad damage on early pregnant mouse and pre-implantation embryos is unavoidable,after the early pregnant mouse is treated with a mild heat stress, the proportion of embryos that developed to morulae or blastocysts and the number of mice embryos was significantly increased , abnormality rates of mice embryos was decreased distinctively,the stage ,the cleavage rate of mice embryos was accelerated obviously.(comparison with that in control group) 4 An uncertain protein with a molecular weight of 70kDa was largely expressed in three discontiguous heat-stressed groups compared to that in acute heat-stressed group and successive heat-stressed group. 5 After pre-treatment with a mild heat stress, the core temperature reduced from 2 hours to 6 hours post heating,the lowest temperature of mice rectum occurred 4 hours post heating,and the weight loss increased after 2 hours post heating. 6 Effect of pre-treatment with maternal heat stress on weight of ovary and uterus had no significant difference with that of control group. 7 Effect of pre-treatment with maternal heat stress on lymphocyte rates of blood had no significant difference with that of control group.