RESUMO
This study evaluated the effect of the protocatechuic acid (PCA) as the sole antioxidant in the base medium for in vitro culture of ovine secondary follicles. Secondary follicles (200-230 µm) were isolated and cultured in α-minimal essential medium supplemented with BSA, insulin, glutamine and hypoxanthine (α-MEM: antioxidant-free medium) or α-MEM also added by transferrin, selenium and ascorbic acid (α-MEM+: with antioxidant) or α-MEM added by PCA (56.25; 112.5; 225; 450; or 900 µg/ml). Moreover, after culture, oocytes were matured and the chromatin configuration and DNA fragmentation were evaluated. After 12 days, the treatment containing 56.25 µg/ml PCA showed higher percentage of normal follicles than control medium or the other treatments (p < .05), except for 900 µg/ml PCA (p > .05). The antrum formation was significantly higher in treatments containing 56.25, 112.5 or 900 µg/ml PCA, compared to the α-MEM and similar (p > .05) to the other treatments. The rates of fully grown oocytes (≥110 µm) were similar (p > .05) among all treatments containing PCA and α-MEM+, and those were superior (p < .05) than α-MEM, except for 450 µg/ml PCA (p > .05). GSH levels and mitochondrial activity were higher (p < .05) in α-MEM+ than in α-MEM and similar (p > .05) to all PCA treatments. The rates of meiotic resumption and DNA fragmentation were similar (p > .05) among α-MEM+ and 56.25 µg/ml PCA. In conclusion, PCA at 56.25 µg/ml as the sole antioxidant added to the medium for ovine isolated secondary follicle culture maintains follicular survival, GSH and active mitochondria levels, meiotic developmental competence and DNA integrity of cultured oocytes.
