Microplastic exposure and its consequences for renal and urinary health: systematic review of <i>in vivo</i> studies

Microplastics (MPs) in the ecosystem have reached an alarming concern as they accumulate in various organs of living organisms, including the kidneys and urinary system. This systematic review aimed to explore the potential harmful effects of microplastics on renal and urinary organs. This study was conducted according to the PRISMA 2020 guidelines, and the SYRCLE tool was used to assess the risk of bias. This review included 77 studies that were published from 2017 to 2024 from various databases, such as PubMed, ScienceDirect, Taylor & Francis, SpringerLink, Wiley Online Library, and ProQuest with PECOS inclusion criteria: (1) Population: Animal; (2) Exposure: All types of exposure to microplastics and/or nanoplastics; (3) Comparison: placebo/control; (4) Outcome: Nephrotoxicity, oxidative stress, inflammation, deposition, and abnormal structure; and (5) Study design: in vivo experimental study. Studies have revealed that microplastics indeed contribute to renal toxicity in the form of deposition within organs; changes in the morphology of renal cells, tissues, and organs; alterations in renal function; and shifts in biomarkers related to injury, inflammation, oxidative stress, metabolism, genetic regulation, and immunity associated with renal health risks.