Comparative investigation of the expression level of autophagy ‎genes (Atg5 and Beclin-1) in mouse MII oocytes after vitrification ‎with two different freezing solutions by cryotop method

Freezing is a long-term egg storage method that plays an important role in assisted reproductive methods. The aim of the present study is to investigate the effect of freezing solutions and docetaxel on the expression changes of autophagy genes such as Atg5 and Beclin-1 in mouse MII oocytes after glass freezing by cryotop method. To achieve this goal, mouse MII oocytes were collected and frozen in two different concentrations of 15% ethylene glycol, 15% dimethyl sulfoxide and 0.5 M sucrose in group A (VS1) and 7.5% ethylene glycol, glycerol. 7.5% and 0.5 M sucrose were frozen in group B (VS2) and some groups were affected by docetaxel before freezing. After thawing, the eggs were fertilized.The percentage of survival and fertilization of frozen and thawed oocytes was evaluated and the expression changes of genes (Atg5 and Beclin-1) were investigated by RT-PCR method. The results showed that there are significant differences between the percentage of survival and the percentage of fertilization in the freezing groups compared to the control group (P<0.05). The percentage of survival and fertilization in the VS1 group decreased compared to the VS2 group. Also, the percentage of survival and conception of the groups pre-incubated with Docetaxel was higher than the non-incubated groups. This study showed that vitrification with cryotop changes the transcript levels of autophagy genes in frozen-thawed MII oocytes, and pre-incubation of oocytes with docetaxel before vitrification can decrease the transcript levels of Atg5 and Beclin-1 in the experimental groups and above Increase the percentage of survival and the percentage of formation of two-celled embryos.