Investigating the Effect of Atorvastatin on the Rate of Apoptosis in Mouse Oocytes

Optimizing cell culture conditions to improve oocyte growth and maturation in vitro culture conditions has been the focus of many researchers today, but the quality improvement mechanism is not fully understood. Apoptosis or programmed cell death is a process to remove old and damaged cells from tissues and plays a major role in the life of follicles and immature oocytes. Most of the defective reproductive cells as well as extra cells are removed from the ovaries through apoptosis. One of the ways to reduce oxidative stress in the laboratory culture of oocyte maturation is the use of antioxidants. Statins are drugs for the treatment of high cholesterol for which antioxidant and anti-apoptotic properties have been reported. Atorvastatin in high doses has side effects for the heart and kidneys, but in low concentrations, it has antioxidant and anti-inflammatory effects for cells, and no side effects have been reported for it.In this study, we investigated the effect of low-dose atorvastatin on the rate of apoptosis in mouse oocytes. 

24 h after PMSG (Pregnant Mare Serum Gonadotropin) inhection, 200 oocytes were obtained from adult female Wistar rats at the age of 4-5 weeks, were from were divided into 2 groups of 100 including the control group (MEM:Minimum Essential Medium culture+ Growth factor) and the atorvastatin group (MEM culture medium + 2 mg/kg atorvastatin+Growth factor) and cultured in the incubator(35 oC,CO2 %). After 24 hours of oocyte culture, Matured oocytes that met the standards of a healthy mature oocyte(oocytes that were in the first meiosis and had the first and mature polar body) were isolated the amount of apoptosis in each group was checked using tunnel staining and fluorescent microscope, the data were analyzed by variance analysis.

After 24 hours of oocyte culture, the amount of apoptosis in the group receiving atorvastatin in the culture medium and the control group was investigated. The rate of apoptosis in the atorvastatin group and the control group was 24% and 22%, respectively, In the atorvastatin group, apoptosis increased by 2% compared to the control group butt the difference between the two groups was not statistically significant (p =0.11).

According to the findings of this study, atorvastatin in low doses can have a pro-apoptotic effect and cause partial induction of apoptosis in mouse oocytes in a laboratory environment. Although this study was not conducted on other doses of atorvastatin, it is suggested that the effect of other doses of this drug on the rate of apoptosis induction should be investigated in order to make an evidence-based decision regarding its administration and use.