Stereological and biochemical effects of thymoquinone on ovarian tissue toxicity induced by silver nanoparticles in NMRI mice: An experimental study

Background: The toxicity of silver nanoparticles (AgNPs) has been proven in the female reproductive system. Thymoquinone (TQ) is a natural antioxidant and bioactive component of Nigella sativa. Objective: We evaluated the efficacy of TQ on ovarian tissue following toxicity induced by AgNPs in female mice. Materials and Methods: 24 female NMRI mice (5-6 wk, an average weight of 33 gr) were randomly divided into 4 groups (n = 6/each): control, AgNPs (500 mg/kg, gavage), TQ (2.5 mg/kg, intraperitoneal injection), and TQ+AgNPs. Mice were treated every day for 35 days. Serum levels of malondialdehyde (MDA), total antioxidant capacity (TAC), luteinizing hormone, and follicle-stimulating hormone were measured. The optical disector and stereological techniques were utilized to estimate the follicular count, their volume at different developmental stages, and the structure of ovarian tissue. Results: In the AgNPs group, the serum concentrations of TAC (p = 0.01), luteinizing hormone (p 0.001), follicle-stimulating hormone, the volume of corpus luteum (p 0.001), and the number of follicles decreased significantly compared to the control group. Nevertheless, AgNPs significantly increased the MDA level. In the TQ+AgNPs group compared to the AgNPs group, a significant decrease in MDA level (p 0.001) and a significant improvement in TAC (p = 0.03), and hormonal levels, the number of primary, preantral, and antral follicles (p = 0.04), and the volume of corpus luteum (p = 0.01) were observed. Conclusion: TQ improved the number of follicles by reducing oxidative stress and lipid peroxidation in AgNPs-damaged ovarian tissue.