Effects of Melatonin and 3,5,3'-Triiodothyronine on the Development of Rat Granulosa Cells

Melatonin, as an endocrine neurotransmitter, can promote the development of the ovary. Meanwhile, it also has protective effect on the ovary as an antioxidant. Thyroid hormone (TH) is essential for normal human reproductive function. Many studies have shown that 3,5,3'-triiodothyronine (T₃) regulates the development of ovarian granulosa cells. However, little is known about the specific mechanisms by which melatonin combines with T₃ to regulate granulosa cell development. The aim of present study was to investigate the effects and the possible mechanisms of melatonin and T₃ on ovarian granulosa cell development. In the present study, cell development and apoptosis were detected by CCK8, EdU and TUNEL, respectively. The levels of related proteins were analyzed by Western blotting. The results showed that oxidative stress (OS) and reactive oxygen species (ROS) were induced by H₂O₂ in granulosa cells, and cell apoptosis was also increased accompanied with the decreased cellular proliferation and viability. Melatonin protects granulosa cells from H₂O₂-induced apoptosis and OS by downregulating ROS levels, especially in the presence of T₃. Co-treatment of cell with melatonin and T₃ also promotes the expression of GRP78 and AMH, while inhibiting CHOP, Caspase-3, and P16. It was demonstrated that melatonin alone or in combination with T₃ had positive effect on the development of granulosa cells. In addition, the AMPK/SIRT1 signaling pathway is involved in the process of melatonin/T₃ promoting granulosa cell development.