The effect of carvacrol on tramadol-induced oxidative renal injury in rats: biochemical and histopathological evaluation

Long-term treatment with tramadol is reported to be toxic to the kidneys. Research shows that tramadol reduces antioxidants and increases oxidants produced in renal tissue. This study aims to investigate the carvacrol effect on tramadol-induced renal injury in rats. The animals were divided into four groups: healthy (HG), individual tramadol (TR), individual carvacrol (CR), and tramadol + carvacrol (TC). Malondialdehyde (MDA), total glutathione (tGSH), glutathione peroxidase (GPO), superoxide dismutase (SOD), total oxidant status (TOS), total antioxidant status (TAS), blood urea nitrogen (BUN), and creatinine (Cr) were measured. Renal tissue was examined histopathologically. MDA, TOS, BUN, and Cr were significantly elevated in group TR and identified as low in group TC compared to group TR but higher than in the HG group. The tGSH, SOD, GPO, and TAS levels were low in group TR and higher in group TC than in group TR but lower than in the HG group. Histological examination of the TR group revealed diffuse necrosis and focal polymorphonuclear leukocytes (PMNLs) in the tubules. In the TC group, tubular atrophy and necrosis were minimal, and PMNL was rare. We observed that tramadol increases oxidants, decreases antioxidants, increases BUN and Cr, and examined whether the toxic effect on renal tissue regressed with carvacrol.