en سم شناسی Toxicology پژوهشي Original Research <strong>Background</strong>: Heavy metal exposure usually causes harmful effects on the environment and human health.&nbsp;<br> <strong>Objectives</strong>: This study investigates the toxic effects of barium chloride (BaCl2) administered at graded doses to adult rats on kidney oxidative stress biomarkers and histological changes.&nbsp;<br> <strong>Methods</strong>: Animals were divided into four groups with six animals in each group. The control group did not receive any treatment, while groups 2, 3, and 4 were exposed to barium at doses of 67, 150, and 300 parts per million for 3 weeks. After recording 24 h urine volumes, samples were collected and stored at -20 ˚C for further analysis. At the end of the experimental period, plasma and kidney tissue were collected for biochemical and histological analysis.&nbsp;<br> <strong>Results</strong>: The treatment of barium can induce nephrotoxicity as evidenced by a significant increase of malondialdehyde (MDA), hydrogen peroxide (H2O2), and advanced oxidation protein product (AOPP). A significant increase in kidney levels of total metallothioneins (MTs) was also observed. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities, reduced glutathione, non-protein thiol, and vitamin C levels showed a significant decline. Plasma creatinine and urea levels showed a significant increase associated with a decrease in uric acid levels. Meanwhile, nephron-biochemical parameters were substantiated by histological examination, revealing disorganized kidney architecture.&nbsp;<br> <strong>Conclusion</strong>: The results highlight significant health concerns regarding environmental barium exposure.&nbsp; Antioxidant, Barium chloride (BaCl2), Metallothionein (MT), Nephrotoxicity, Rats 319 330 http://pbr.mazums.ac.ir/browse.php?a_code=A-10-1285-1&slc_lang=en&sid=1 Elwej Awatef awatefelwej@yahoo.fr 100319475328460010607 100319475328460010607 Yes Animal Physiology Laborator, Sfax Faculty of Sciences, Sfax University, Sfax, Tunisia. Mariem Chaabane mariamchaban1@gmail.com 100319475328460010608 100319475328460010608 No Animal Physiology Laborator, Sfax Faculty of Sciences, Sfax University, Sfax, Tunisia. Imen Ghorbel imengorbel@hotmail.com 100319475328460010609 100319475328460010609 No Animal Physiology Laborator, Sfax Faculty of Sciences, Sfax University, Sfax, Tunisia. Samira Jebahi samirajbehi3@gmail.com 100319475328460010610 100319475328460010610 No Biochemistry Laboratory, CHU Hedi Chaker, University of Sfax, Sfax, Tunisia. Rim Marrekchi rimmarrakch1@yahoo.fr 100319475328460010611 100319475328460010611 No Anatomopathology Laboratory, CHU Habib Bourguiba, Sfax University, Sfax, Tunisia. Tahia Boudawara tahiasallemi1@yahoo.com 100319475328460010612 100319475328460010612 No Animal Physiology Laborator, Sfax Faculty of Sciences, Sfax University, Sfax, Tunisia. Najiba Zeghal nejibazegal@gmail.com 100319475328460010613 100319475328460010613 No Animal Physiology Laboratory. Sfax Faculty of Sciences.BP1171, 3000 Sfax. Sfax University, Tunisia