Olfactory dysfunction induced by pesticides: Adverse outcomes, emerging mechanisms, and risk for neurodegenerative...

Pesticide pollution has recently emerged as a growing global concern. There is a broad consensus that environmental exposure levels of pesticides are neurologically toxic to animals. Olfaction, an integral component of the nervous system, comprises a peripheral system for detecting odors and a central system for electrical signal processing and plays a key role in food acquisition and reproductive behavior. The olfactory system is easily disrupted by pesticides, resulting in olfactory dysfunction (OD). This review systematically summarized the occurrence of OD and its adverse outcomes in humans, mice, fish and insects. Emerging mechanisms in model animals were also outlined, especially those involving calcium homeostasis and neuronal apoptosis. Given the evolutionary conservation of the olfactory system, findings from model animals provide valuable insights into the mechanisms underlying OD in humans. Epidemiological evidence has established that pesticide exposure not only induces OD but also exacerbates neurodegenerative diseases (NDs). Considering that OD-related biomarkers have been employed for the early diagnosis of NDs, this review aimed to expand our understanding of novel advances and directions in pesticide-induced OD and to highlight the critical role of model animals in laying a scientific reference for exploring novel OD-related biomarkers for the clinical diagnosis of NDs.