The Protective Effect of Thiamine and Thiamine Pyrophosphate Against Linezolid-Induced Oxidative Liver Damage and Lactic Acidosis in Rats

Linezolid, an antimicrobial agent, has been linked to lactic acidosis, oxidative stress, and liver damage. Oxidative stress is considered to play a key role in this damage. Thiamine pyrophosphate (TPP), the active form of thiamine, may prevent lactate accumulation and enhance aerobic capacity. Therefore, this study aimed to evaluate the protective effect of TPP against possible linezolid-induced liver damage and lactic acidosis in rats. Twenty-four male Wistar albino rats were randomly assigned to four groups (n = 6): healthy control (HG), linezolid (LZD), thiamine plus linezolid (TLZD), and TPP plus linezolid (TPLZD). Thiamine and TPP (20 mg/kg, intraperitoneal (i.p.)) were administered once daily, while linezolid (125 mg/kg, per os (p.o.)) was given twice daily (250 mg/kg/day) for 28 days. Animals were euthanized under high-dose anesthesia (with 50 mg/kg, i.p. thiopental sodium). Liver tissues were analyzed for MDA, tGSH, SOD, and CAT, and examined histopathologically. Blood samples were collected prior to euthanasia to assess lactate, LDH, ALT, AST, and TPP levels. In the LZD group, MDA, lactate, ALT, AST, and LDH levels significantly increased, while tGSH, SOD, CAT, and TPP decreased (p < 0.001). Histopathology showed hydropic degeneration, necrosis, and mononuclear cell infiltration (p < 0.05). Thiamine did not prevent these alterations (p > 0.05), whereas TPP significantly prevented both biochemical and histopathological changes (p < 0.05), indicating its protective efficacy. TPP may offer significant protection against linezolid-induced hepatotoxicity and lactic acidosis. © 2025 by the authors.