Curcumin Delays Oocyte Apoptosis Through Overexpression of BCL-2 Gene in Young and Middle-Aged Mouse Models

Oxidative stress can initiate the process of apoptosis which affects the oocyte quality and reduces development competency in the ovarian follicles. Accordingly, the present study determined the effects of curcumin as a well-known antioxidant on the apoptosis prevention of mature oocytes during the natural increasing age in female mice.

In this case-control, interventional, and quantitative applied research, 21-day-old NMRI (Naval Medical Research Institute) female mice were used as control, vehicle, and curcumin groups. The mice in the curcumin group received 100 mg/kg/d curcumin intraperitoneally. After initial interventions, the Annexin-V-FLUOS staining was applied to evaluate the oocyte apoptosis rate in the three groups at 6, 12, and 33 weeks of age. The expression of oocytes apoptosis-related genes (Bcl2 and Bax) was also assessed by the real-time polymerase chain reaction (PCR) technique, followed by measuring oxidation-reduction markers in the ovaries.

Our results showed that oocyte apoptosis and necrosis in the curcumin group decreased in comparison with the control and vehicle groups at 12 and 33 weeks (P < 0.001). Moreover, the use of curcumin led to the upregulation of Bcl2 and downregulation of Bax genes at 6, 12, and 33 weeks (P < 0.001). In addition, the superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities increased in the curcumin group compared with control and vehicle groups at 12 and 33 weeks (P < 0.001) while malondialdehyde (MDA) decreased in the curcumin group at 12 (P < 0.001), in the control at 12 (P < 0.01), and in the vehicle at 33 weeks (P < 0.01).

In general, curcumin could suppress oocyte apoptosis through upregulating Bcl2 and the downregulating of Bax gene, as well as suppressing oxidative stress pathways involving oocyte apoptosis and necrosis.