Long-life triclosan exposure induces ADHD-like behavior in rats via prefrontal cortex dopaminergic deficiency

Abstract

In recent years, exposure to triclosan (TCS) has been linked to an increase in psychiatric disorders. Nonetheless, the precise mechanisms of this occurrence remain elusive. Therefore, this study developed a long-life TCS-exposed rat model, an SH-SY5Y cell model, and an atomoxetine hydrochloride (ATX) treatment model to explore and validate the neurobehavioral mechanisms of TCS from multiple perspectives. In the long-life TCS-exposed model, pregnant rats received either 0 mg/kg (control) or 50 mg/kg TCS by oral gavage throughout pregnancy, lactation, and weaning of their offspring (up to 8 weeks old). In the ATX treatment model, weanling rats received daily injections of either 0 mg/kg (control) or 3 mg/kg ATX via intraperitoneal injection until they reached 8 weeks old. Unlike the TCS model, ATX exposure only occurred after the pups were weaned. The results indicated that long-life TCS exposure led to attention-deficit hyperactivity disorder (ADHD)-like behaviors in male offspring rats accompanied by dopamine-related mRNA and protein expression imbalances in the prefrontal cortex (PFC). Moreover, in vitro experiments also confirmed these findings. Mechanistically, TCS reduced dopamine (DA) synthesis, release, and transmission, and increased reuptake in PFC, thereby reducing synaptic gap DA levels and causing dopaminergic deficits. Additional experiments revealed that increased DA concentration in PFC by ATX effectively alleviated TCS-induced ADHD-like behavior in male offspring rats. These findings suggest that long-life TCS exposure causes ADHD-like behavior in male offspring rats through dopaminergic deficits. Furthermore, ATX treatment not only reduce symptoms in the rats, but also reveals valuable insights into the neurotoxic mechanisms induced by TCS.

Keywords

• Triclosan
• Dopamine
• ADHD
• Atomoxetine hydrochloride