Citrinin exposure disrupts organelle distribution and functions in mouse oocytes

Citrinin (CTN) is a secondary fungal metabolite produced by several species of Aspergillins and Penicillins, and it is widely found in vegetable-derived foods such as cereals and fermented rice-based food supplements. Previous studies indicated that CTN had immunotoxicity, hepatotoxicity, nephrotoxicity, and reproductive toxicity, which caused severe effects on human and animal health. However, the potential toxicity of CTN on the organelles of mouse oocytes is still unclear. In this study, we showed that the exposure to 30 μM CTN significantly reduced the developmental capacity of mouse oocytes. Our results revealed that mitochondria exhibited abnormal distribution and mitochondrial membrane potential decreased under CTN exposure. And the endoplasmic reticulum (ER) failed to accumulate to the spindle periphery, which is accompanied by the occurrence of ER stress, showing with increased GRP78 expression. We also found that similar with ER, the Golgi apparatus showed homogenous localization pattern after CTN exposure, and the vesicle transport was disturbed, showing with aberrant expression and localization of Rab11a. Moreover, our results indicated that CTN exposure increased the expression of LAMP2, indicating the induction of lysosomal damage. In summary, our study showed that CTN exposure to mouse oocytes was toxic to the distribution and functions of organelles, which further led to a decrease of oocyte quality.