Dimethomorph Exposure Impairs Human Granulosa Cells and Mouse Ovarian Physiology
Dimethomorph (DMM) is a widely used fungicide recently classified as a reproductive toxicant, yet its effects on female reproductive function remain poorly understood. This study aimed to determine whether DMM reaches the human ovarian follicular environment and to investigate its effects on granulosa cell function and ovarian physiology. DMM was detected in both human plasma and follicular fluid, demonstrating that this fungicide can reach the ovarian follicular microenvironment. In vitro, primary human granulosa cells and KGN cells were exposed to DMM at 1, 10, 100, 400, and 4000 ng/mL for 24 h (proliferation, steroidogenesis, oxidative stress and gene expression) or for 24–72 h (cell viability). DMM had minimal effects on cell viability but significantly reduced granulosa cell proliferation, increased oxidative stress, impaired basal steroidogenesis, and selectively inhibited IGF-1-stimulated estradiol and progesterone secretion. RNA sequencing performed on primary human granulosa cells exposed to 1 and 100 ng/mL DMM revealed major alterations in steroidogenic pathways, cholesterol metabolism, and glucocorticoid signaling, including the downregulation of CYP11A1, CYP19A1, and HSD17B1. In vivo, female Swiss mice chronically exposed to DMM (1 µg/kg/day) exhibited disrupted estrous cyclicity, reduced LH and FSH concentrations, decreased ovarian expression of genes involved in folliculogenesis and steroidogenesis, and significantly fewer growing follicles and corpora lutea. Overall, these findings identify dimethomorph as a potential ovarian endocrine disruptor capable of impairing granulosa cell function and ovarian physiology, highlighting possible risks for female fertility following environmental exposure.
Dimethomorph (DMM) is a widely used fungicide recently classified as a reproductive toxicant, yet its effects on female reproductive function remain poorly understood. This study aimed to determine whether DMM reaches the human ovarian follicular environment and to investigate its effects on granulosa cell function and ovarian physiology. DMM was detected in both human plasma and follicular fluid, demonstrating that this fungicide can reach the ovarian follicular microenvironment. In vitro, primary human granulosa cells and KGN cells were exposed to DMM at 1, 10, 100, 400, and 4000 ng/mL for 24 h (proliferation, steroidogenesis, oxidative stress and gene expression) or for 24–72 h (cell viability). DMM had minimal effects on cell viability but significantly reduced granulosa cell proliferation, increased oxidative stress, impaired basal steroidogenesis, and selectively inhibited IGF-1-stimulated estradiol and progesterone secretion. RNA sequencing performed on primary human granulosa cells exposed to 1 and 100 ng/mL DMM revealed major alterations in steroidogenic pathways, cholesterol metabolism, and glucocorticoid signaling, including the downregulation of CYP11A1, CYP19A1, and HSD17B1. In vivo, female Swiss mice chronically exposed to DMM (1 µg/kg/day) exhibited disrupted estrous cyclicity, reduced LH and FSH concentrations, decreased ovarian expression of genes involved in folliculogenesis and steroidogenesis, and significantly fewer growing follicles and corpora lutea. Overall, these findings identify dimethomorph as a potential ovarian endocrine disruptor capable of impairing granulosa cell function and ovarian physiology, highlighting possible risks for female fertility following environmental exposure.