en Neurophysiology/Pharmacology Neurophysiology/Pharmacology Experimental research article Experimental research article <p><span style="font-size:12px;"><span style="font-family:Arial;"><span style="line-height:115%"><b>Introduction: </b>The molecular mechanisms underlying chemotherapy-associated hippocampal neurodegeneration, particularly following exposure to alkylating agents, remain poorly understood. This study investigated the association between melphalan- and chlorambucil-induced hippocampal injury and alterations in apoptosis-, autophagy-, and miR-204-related pathways.<br /> <b>Methods</b>: Adult male Wistar rats were treated daily for 30 days with saline (control), Mel, or Chl. Hippocampal tissue was analyzed using histological assessment of dark neurons and qRT-PCR analysis of apoptosis-related genes (Bax, Bcl-2, Caspase-3), autophagy-related genes (LC3&beta; and Beclin-1), and miR-204 expression.<br /> <b>Results</b>: Both Mel and Chl significantly increased the density of dark neurons in the hippocampus compared with the control group. Molecular analysis revealed increased expression of the pro-apoptotic genes BAX and Caspase-3 together with reduced expression of the anti-apoptotic gene BCL2. In addition, the expression levels of the autophagy-related genes LC3&beta; and Beclin-1 were significantly decreased following treatment. Furthermore, miR-204 expression was significantly upregulated in both Mel and Chl groups and was associated with hippocampal neurodegeneration, increased expression of apoptosis-related genes, and reduced expression of autophagy-related genes.<br /> <b>Conclusion</b>: These findings indicate that systemic exposure to melphalan and chlorambucil is associated with hippocampal neurodegenerative changes accompanied by altered expression of apoptosis- and autophagy-related genes. The consistent upregulation of miR-204 suggests that this microRNA may contribute to alkylating agent-associated hippocampal neurodegeneration; however, further functional studies are required to determine its mechanistic role and therapeutic relevance in chemotherapy-related cognitive impairment.</span></span></span></p> Hippocampal,Neurodegeneration,Melphalan,Chlorambucil,microRNA-204 0 0 http://ppj.phypha.ir/browse.php?a_code=A-10-2328-2&slc_lang=en&sid=1 Amirhossein Ebadi ebadi.amirhossein0282@yahoo.com 3200319475328460039339 3200319475328460039339 No Student Research Committee, Gonabad University of Medical Sciences, Gonabad, IR Iran. maryam moghimian moghimian2@yahoo.com 3200319475328460039340 3200319475328460039340 No Department of Physiology, Faculty of Medicine, Gonabad University of Medical Sciences, Gonabad, IR Iran Samira eyzi eziysamira@gmail.com 3200319475328460039341 3200319475328460039341 No Department of Anatomy, School of Medicine, Gonabad University of Medical Sciences, Gonabad, IR Iran zahra saadatian z.saadatian@yahoo.com 3200319475328460039342 3200319475328460039342 No Department of Physiology, Faculty of Medicine, Gonabad University of Medical Sciences, Gonabad, IR Iran Vida Alikhani vd.alikhani@gmail.com 3200319475328460039343 3200319475328460039343 No Department of Physiology, Faculty of Medicine, Gonabad University of Medical Sciences, Gonabad, IR Iran malihe soltani soltanimalihe@yahoo.com 3200319475328460039344 3200319475328460039344 Yes Malihe Soltani, Associate Professor, Department of Anatomy, School of Medicine, Gonabad University of Medical Sciences, Gonabad, IR Iran