en Cell Biology Cell Biology Original Article Original Article <div style="text-align: justify;"><span style="font-size:12px;"><span style="font-family:Tahoma;"><span style="line-height:14.0pt"><span style="color:black">Cardiotoxicity represents a significant adverse effect associated with 5-fluorouracil (5-FU), a widely used chemotherapeutic agent. Melatonin (MLT), a powerful antioxidant and agent that prevents apoptosis, has shown promise in mitigating various toxicities. This study evaluated the cardioprotective effect of MLT on 5-FU-induced cardiotoxicity (5-FU-IC) in the H9c2 cardiomyoblast cell line. </span></span><br> <span style="line-height:14.0pt"><span style="color:black">The cells were grown in DMEM + FBS and divided into four groups: control (untreated), 5-FU-treated (varying concentrations for 48 hours), MLT-treated (varying concentrations), and 5-FU plus MLT-treated (combined treatment for 48 hours). The cell viability was evaluated using the MTT assay, while apoptosis was analyzed through flow cytometry following Annexin V staining and caspase-3/7 (Cas-3/7) activity assays.</span></span><br> <span style="line-height:14.0pt"><span style="color:black">Treatment with 5-FU led to a significant decrease in the viability of H9c2 cells in a dose-dependent fashion, with an estimated IC50 value of 400 &mu;M. Co-treatment with MLT at 100 and 200 &mu;M significantly enhanced cell viability and reduced apoptosis induced by 5-FU, as demonstrated by flow Cytometry and reduced Cas-3/7 activity. These results emphasize the protective effects of MLT against 5-FU-IC, primarily through its anti-apoptotic mechanisms.</span></span><br> <span style="line-height:14.0pt"><span style="color:black">These findings underscore the importance of MLT to protect against 5-FU-IC through its anti-apoptotic properties. MLT shows promise as a cardioprotective agent in mitigating 5-FU-IC, providing perspectives on its potential therapeutic application in mitigating cardiac risks linked to chemotherapy.</span></span></span></span><br> &nbsp;</div> Melatonin, 5-Fluorouracil, Apoptosis, Cardiotoxicity, Chemotherapy, H9c2 cells 843 855 http://ijmcmed.org/browse.php?a_code=A-10-5114-1&slc_lang=en&sid=1 Sama Torkashvand s.torkashvand1374@gmail.com 100319475328460035513 100319475328460035513 No Student Research Committee, Health Research Institute, Babol, Iran Sohrab Kazemi kazemi.msm@gmail.com 100319475328460035514 100319475328460035514 No Cellular and Molecular Biology Research Center, Health Research Institute, Babol, Iran Razieh Mansoori mansoorirazieh@gmail.com 100319475328460035515 100319475328460035515 No Student Research Committee, Health Research Institute, Babol, Iran Ali Akbar Moghadamnia aliamoghadamnia@gmail.com 100319475328460035516 100319475328460035516 No Pharmaceutical Sciences Research Center, Health Research Institute, Babol, Iran Manouchehr Ashrafpour mnrashrafpour@yahoo.com 100319475328460035517 100319475328460035517 Yes Mobility Impairment Research Center, Health Research Institute, Babol, Iran