Objective: To study the effects of cigarette smoke on the oxidative damage of mice oocytes and developmental potential.
Methods: A total of 96 SPF grade 6-week-old ICR female mice were randomly divided into control group, low-dose group, middle-dose group and high-dose group according to the principle of similar body weight. Twenty-four mice in each group were placed in a cigarette-lighting containers with the volume of 60, 32 and 23 L respectively. The control group was fed normally twice a day for 1 hour for 4 weeks. Weight and record daily, draw weight change curve; use kit to detect the activity of superoxide dismutase(SOD) and glutathione peroxidase(GPX) in ovarian tissue; use tissue section, indirect immunofluorescence and in vitro maturation technology to detect the activity of each group. The ovarian organ index, the level of reactive oxygen species(ROS) in oocyte and the first polar body rate were measured. The t test was used to compare the mean values of the two groups, and one-way ANOVA was used to compare the mean values of the multiple groups.
Results: Compared with the control group, the weight gain of mice in the treatment group was significantly slower(the weight gain in the high dose group was only 1. 05%±0. 41%). The ovarian organ index, SOD and GPX activity in the ovarian tissue and litter size(the high dose group was reduced to 5. 20%±1. 48%) were significantly decreased. The ROS level in oocyte was significantly increased, and oocyte maturation in vitro was the first. The polar body rate decreased(high dose group decreased to 49. 34%±5. 78%), and the difference was statistically significant(P<0. 05).
Conclusion: Cigarette smoke exposure in mice can cause the decrease of ovarian organ index, SOD and GPX activity, the increase of ROS content in oocyte, the decrease of first polar body rate and litter size.
Keywords: cigarette smoke; mice; oocytes; oxidative damage; reproductive capacity.