Effect of cigarette smoke and alpha-tocopherol (vitamin E) on fertilization, cleavage, and embryo development rates in mice: An experimental in vitro fertilization mice model study

Abstract 

Objective

The objective was to elucidate the effects of cigarette smoke per se or vitamin E on mice exposed to cigarette smoke, with regard to fertility and cleavage rates, and embryo development in an experimental in vitro fertilization (IVF) mice model.

Study design

Female and male mice, weighing 18–25g and aged 14–16 weeks, were separated and divided into cigarette smoke-exposed (SE) and non-smoke-exposed (NSE) groups. A specially designed cage with a cigarette smoking machine was constructed. The SE (20cigarettes/day) group was put in the cage for 10 weeks. SE and NSE female and male mice were given 50mg/kg of vitamin E intraperitoneally for 10 weeks and were cross-mated thereafter so as to produce seven different subgroups of mice population as follows: group I-NSE male and female mice (control); group II-SE female mice and NSE male mice; group III-NSE female with SE male mice; group IV-SE male and SE female mice; group V-SE female mice treated with vitamin E and SE only male mice; group VI-SE only female and male mice treated with vitamin E; and finally group VII-vitamin E-treated SE male and female mice.

Following superovulation with FSH, follicles of female mice were obtained via laparotomy under high-dose ether. Male mice testicles were retrieved via the same surgical procedure. Both gametes were obtained and used for IVF. Fertilization, cleavage rates, and day 3 embryo grading were assessed in four groups.

Results

With regard to fertilization rate, group II (36%) significantly differed from group I (85%, p=0.002), group III (68.7%, p=0.04), but not from group IV (20.6%, p=0.34). Taking embryo development rate into consideration, group II (32%) had a lower percentage of embryo development compared with group I (75%, p<0.01) and group III (62.5%, p<0.001), but not group IV (17.2%, p=0.42). Percentages of embryo cleavage, embryo development, and day 3 grade I embryos did differ among four of the groups (p>0.05).

Conclusions

Fertilization and cleavage rates were mainly affected in the SE female mice population. The impact of vitamin E on fertilization, cleavage, and embryo development rates was not relevant among SE male and SE female mice.

Keywords: Cigarette smoke, Vitamin E, In vitro fertilization, Mice model