Imazamox‐Induced Hematotoxicity, Oxidative Stress, Inflammation, and DNA Damage in Rainbow Trout: Modulatory Effects of Borax

Imazamox (IMZMX) is an imidazolinone herbicide that may reach aquatic environments and affect non-target organisms. This study evaluated acute IMZMX toxicity and the potential modulatory effects of borax (BRX) in rainbow trout (Oncorhynchus mykiss) using hematological, stress, oxidative/antioxidant, inflammatory, DNA-damage, and apoptotic biomarkers. Fish were assigned to control, IMZMX, IMZMX + BRX, and BRX groups and sampled after 48 and 96 h. IMZMX exposure reduced red blood cell (RBC) count, hemoglobin (Hgb), and hematocrit (Hct), with associated changes in mean corpuscular volume (MCV), mean corpuscular Hgb (MCH), and MCH concentration (MCHC). Cortisol increased significantly in the IMZMX group at 48 and 96 h, consistent with an acute stress response. IMZMX also disrupted antioxidant homeostasis, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and reduced glutathione (GSH), and increased malondialdehyde (MDA) and myeloperoxidase (MPO), indicating enhanced oxidative injury. Changes in nuclear factor erythroid 2-related factor 2 (Nrf2), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α) further indicated redox-sensitive inflammatory modulation. In addition, IMZMX increased 8-hydroxy-2'-deoxyguanosine (8-OHdG) and caspase-3, supporting oxidative DNA damage and apoptosis. Co-exposure to BRX generally shifted several altered biomarkers toward control values, suggesting a protective or modulatory effect under the tested acute conditions. These findings support further investigation of boron compounds as context-dependent modulators of pesticide-induced oxidative injury in fish, while emphasizing the need to define dose-, route-, and duration-dependent safety limits.