Triclosan induces DNA damage in human ovarian granulosa cells via mitochondrial superoxide overproduction mediated by suppressed glutathione synthesis.

Abstract

Triclosan (TCS) is a broad-spectrum antimicrobial agent that has raised public health concerns due to its continuous environmental release and human exposure. Previous studies suggest that TCS may disrupt endocrine function. Nonetheless, the toxicological effects on the female reproductive system, notably on ovarian granulosa cells, and the underlying pathways remain poorly understood. This study was designed to examine the toxic effects of TCS on human granulosa cells and the related mechanisms. To this end, human granulosa cell lines (KGN and SVOG) were treated in vitro with varying doses of TCS. The results demonstrated that TCS exposure led to marked cytotoxicity and DNA damage in a dose-dependent manner. Transcriptomic profiling showed that TCS markedly affected pathways associated with mitochondrial respiratory chain function and DNA repair mechanisms within granulosa cells. Subsequent mechanistic studies revealed that TCS led to mitochondrial dysfunction, as evidenced by reduced activity of mitochondrial respiratory chain complex I and a marked increase in mitochondrial ROS levels. Application of the mitochondria-targeted antioxidant MitoTEMPOL significantly alleviated the ROS accumulation and DNA damage induced by TCS. Specifically, we found that TCS exposure suppressed the synthesis of glutathione (GSH), a key component of the endogenous antioxidant defense system. The decline in GSH synthesis was further confirmed to be an upstream initiating factor for TCS-induced mitochondrial ROS production and DNA damage in granulosa cells, as evidenced by glutathione monoethyl ester (GSH-MEE) pretreatment. These findings reveal a previously unrecognized molecular mechanism by which TCS impairs ovarian reserve function, thereby providing important theoretical insights for assessing the reproductive toxicity risk of TCS and suggesting that antioxidants targeting GSH and mitochondria may represent a potential intervention strategy.