The subtle balance of insulin and thyroxine on survival and development of in vitro cultured caprine preantral follicles enclosed in ovarian tissue

• Published in: Theriogenology 2020-04, Vol.147, p.10-17
• Main Authors: Paes, V.M., Lima, L.F., Ferreira, A.C.A., Lobo, C.H., Alves, B.G., Rodrigues, A.P.R., Oliveira, A.C., Figueiredo, J.R., Feugang, J.M.
• Format: Article
• Language: English
• Subjects: Animals; Caprine ovary; Dose-Response Relationship, Drug; Estradiol - biosynthesis; Female; Gene Expression Regulation; Goats; Insulin; Insulin - administration & dosage; Insulin - pharmacology; Ovarian Follicle - physiology; Primordial follicles; Reactive Oxygen Species; Thyroxin; Thyroxine - administration & dosage; Thyroxine - pharmacology; Tissue Culture Techniques
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2020.01.013

Numerous studies have reported the importance of thyroid hormones on the development of later preantral and antral follicles, but their interactions with other hormones and effects in regulating early preantral follicle growth remain unclear. Here we investigated the in vitro effects of thyroxine combined with insulin on caprine preantral follicle survival and development. Sliced ovarian tissues were cultured for 1 or 7 days using 10 ng/mL (low) or 10 μg/mL (high) insulin in the presence of thyroxine at 0, 0.5, 1 or 2 μg/mL. Post-culture, we evaluated the follicular survival and development, assessed the expression of apoptotic-related genes (Bcl2/Bax) and receptors of insulin and thyroid hormones, and quantified the estradiol and reactive oxygen species (ROS) production levels. Follicular survival in low-insulin culture conditions was enhanced by the presence of 0.5 μg/mL thyroxine (P  0.05). Significantly higher ROS production was measured from Day 1 to Day 7 in low-insulin culture media containing 0.5 or 2 μg/mL thyroxine (P