Micro- and Nanoplastics as Disruptors of the Endocrine System-A Review of the Threats and Consequences Associated with Plastic Exposure.

Plastic overconsumption has emerged as a major environmental pollutant, with degraded micro- and nanoplastic (MNP) particles being consumed by a vast variety of species. MNPs, particles < 5 mm, contain endocrine-disrupting chemicals (EDCs), which can bind to hormone receptors and disrupt the proper endocrinological function of a variety of organs. This review explores the toxicological impact of MNPs on the hypothalamus, pituitary gland, thyroid, pineal body, ovaries, and testes, as well as the effects of the endocrinological regulatory axes, including the hypothalamic-pituitary-gonadal (HPG), hypothalamic-pituitary-thyroid (HPT), and hypothalamic-pituitary-adrenal (HPA) axes. The disruption of these hormonal feedback systems leads to reproductive dysfunction, neurotoxicity, cytotoxicity, immunotoxicity, and metabolic disorders. The gonads are particularly susceptible, with studies demonstrating oxidative stress, cellular apoptosis, and infertility due to MNP exposure. Given the widespread presence of MNPs and their impact on human health, further research is critical to understand their long-term effects and develop strategies to reduce exposure.