Arsenic (As) is a toxic substance that can cause damage to liver and kidney tissues. Many studies showed that exposure to small amounts of this substance induces oxidative stress and causes kidney injury through the formation of free radicals. Accumulation of these non-essential metals can occur over many years, especially in the kidneys. Extracellular vesicles (EVs) facilitate intercellular communication and include exosomes, ectosomes, and apoptotic bodies. EVs are secreted through endosomes

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... nd carry genetic materials and proteins. Recently, EVs have become the focus as a novel molecular target in diagnosis and treatment. EVs cargo, including mRNA and miRNA, have a significant function in stabilizing and the identification of exosomes and their function. miRNA is a post-transcriptional gene suppressor that may act as an indicator and early warning in developing pathogenesis in heavy metal toxicity. Kidney EVs are execrated from podocytes. We collected random urine samples from 20 rats which were exposed orally to ArsenicV and evaluated the universal kidney function, including a novel molecular target in the diagnosis of glomerulonephritis. Results showed that medium to high doses of arsenic, prior to kidney damage, could elevate exosome-containing mRNA and miRNA. The primary effect of arsenic at the cellular level could increase oxidative defense gene expression, including nuclear factor erythroid 2–related factor 2 (NRF2) antioxidant system, which increases the novel miRNA biomarker miR-21 and miR-342. In conclusion, our findings shows that exposure to arsenic with initial effects can elevate exosomal miR-342 as well as miR-21.