The synergistic role of cysteamine and Citrus sinensis peel essential oil on the in vitro maturation of porcine oocyte

The combined use of Citrus sinensis essential oil (EOCS) and cysteamine (CYS) can improve oxidative changes in porcine oocytes, boosting in vitro maturation (IVM) rates. This study evaluated the synergistic effect of EOCS and CYS on oocyte IVM using different EOCS concentrations: (i) 100 µM CYS (control), (ii) 10 µg/mL EOCS (10EOCS + CYS), (iii) 30 µg/mL EOCS (30EOCS + CYS), and (iv) 50 µg/mL EOCS (50EOCS + CYS). The optimal EOCS concentration was then compared to its synergistic or substitutive effect with CYS: (i) CYS (CYS group), (ii) the best EOCS concentration with CYS (EOCS + CYS), and (iii) the best EOCS concentration (EOCS group). The 50EOCS + CYS group performed better than the control with higher cumulus cell viability (92.4±0.6% vs. 75.1±4.9%), improved mitochondrial pattern (85.7±11.1% vs. 63.0±3.03%), and lower reactive oxygen species (ROS) levels (0.62±0.17 vs. 1.00±0.44). In the second experiment, while cumulus cell expansion, nuclear maturation, and ROS levels showed no differences, 50EOCS (92.4±0.6%) achieved better cumulus cell viability. It was concluded that 50EOCS did not exhibit a synergistic effect with CYS but was a viable alternative for porcine IVM.