Melatonin ameliorates the toxic effects of 2,6-Dichloro-1,4-benzoquinone on mouse oocytes by restoring subcellular structures.

2,6-Dichloro-1,4-benzoquinone (2,6-DCBQ) is a disinfection by-product (DBP) formed during the disinfection of drinking water. Due to its frequent detection and high concentrations, it has garnered significant attention. However, the effects of 2,6-DCBQ on oocyte meiosis remain poorly understood. In this study, we demonstrate that 2,6-DCBQ exposure disrupts nuclear maturation in oocytes by damaging the spindle and chromosome structure. Additionally, exposure to 2,6-DCBQ impairs cytoplasmic maturation by altering actin dynamics, disrupting cortical granule distribution, and compromising the function of key organelles, including the mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes. Supplementing melatonin during meiotic maturation reverses these effects, enhancing organelle function, reducing reactive oxygen species (ROS) levels, alleviating DNA damage, and inhibiting apoptosis. Together, these findings show that 2,6-DCBQ causes organelle dysfunction and meiotic disruption in oocytes, while melatonin provides protective effects against these disruptions during meiotic maturation.