en Cell, Stem Cell and Cancer Cell, Stem Cell and Cancer Experimental research article Experimental research article <div style="text-align: justify;"><strong><span class="fontstyle0">Introduction: </span></strong><span class="fontstyle2">Diethylhexyl phthalate (DEHP) is leaching form polyvinyl chloride to cause animal toxicity. In our previous study, DEHP caused osteoblasts mortality </span><span class="fontstyle3">in vitro</span><span class="fontstyle2">, since rat bone marrow mesenchymal stem cells (MSCs) is the cellular back up for osteoblasts; therefore its effect on MSCs was investigated. </span><strong><span class="fontstyle0">Methods: </span></strong><span class="fontstyle2">MSCs were extracted from Westar rats and treated with 0.5 to 2500&mu;M of DEHP for 12, 24 and 48h to study the viability. Then further investigations, including proliferation, cell morphology, sodium and potassium level, concentration of calcium, total protein, activity of metabolic enzymes (ALT, AST, ALP, LDH), malondialdehyde (MDA) level, total antioxidant capacity, activity of superoxide dismutase (SOD) and catalase (CAT) were measured using selected concentration (100, 500 and 1500&mu;M). </span><span class="fontstyle0"><strong>Results:</strong> </span><span class="fontstyle2">The 100&mu;M of DEHP did not change the viability and biochemical factor after 48h but colony forming assay and population doubling number was significantly affected. Th 500&mu;M only reduced the viability at 24 and 48h, while 1500&mu;M caused the significant reduction at all the periods. These two concentrations, caused significant proliferation reduction as well as significant increase in calcium and sodium level, LDH activity and MDA level. In addition, we observed decrease in potassium, total protein, activity of metabolic enzymes and activity of CAT and SOD significantly. </span><span class="fontstyle0"><strong>Conclusion:</strong> </span><span class="fontstyle2">DEHP has reduced viability and proliferation of MSCs through metabolic change, alteration in cellular ultrastructure, ionic imbalance and induction of oxidative stress.</span></div> Mesenchymal Stem Cell, Diethylhexyl phthalate, Oxidative stress, Cell survival, Enzymes assay. 88 100 http://ppj.phypha.ir/browse.php?a_code=A-10-432-2&slc_lang=en&sid=1 Mohammad Hussein Abnosi m-abnosi@araku.ac.ir 3200319475328460030502 3200319475328460030502 Yes Department of Biology, Faculty of Sciences, Arak University, Arak, Iran Zahra Aliyari Babolghani 3200319475328460030503 3200319475328460030503 No Department of Biology, Faculty of Sciences, Arak University, Arak, Iran