Morphological changes in ovarian follicles, stromal cells, and extracellular matrix in cryopreserved cattle ovarian tissue and the beneficial effects of Croton argyrophyllus Kunth essential oil.

This study examined morphological changes in preantral follicles, stromal cells, and the extracellular matrix of cattle ovarian tissue vitrified in medium supplemented with Croton argyrophyllus Kunth essential oil (CaEO). Ovarian cortical slices were cryopreserved using solid surface vitrification in α-MEM+ alone (control) or supplemented with 0.01, 0.1, 1.0, or 10.0 μg/mL CaEO. After thawing, the ovarian fragments were cultured for 24 h. Then, follicular morphology, stromal cells, collagen distribution, thiol levels, and the activity of enzymatic antioxidants catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX) were analyzed. Histological analysis revealed an increased rate of healthy follicles in the ovarian tissues vitrified in medium supplemented with CaEO in comparison to the control group. However, no significant differences were found in the rate of primordial follicle activation (P < 0.05). Collagen fibers were more abundant in fragments vitrified with 0.1, 1, or 10 μg/mL CaEO than in those stored with 0.01 μg/mL CaEO or in the control medium (P < 0.05). A higher thiol content was observed in tissues cryopreserved with 1 or 10 μg/mL CaEO than in the control group (P < 0.05). Catalase activity was greater in samples stored in the presence of 0.01 or 0.1 μg/mL CaEO than in tissue cryopreserved with 10 μg/mL CaEO (P < 0.05). In conclusion, CaEO enhances the efficiency of cryopreservation by preserving follicular health, increasing collagen fibers, and regulating antioxidant enzyme activity.