Nephrotoxicity and oxidative stress of single large dose or two divided doses of gentamicin in rats

Gentamicin (GS) is a potent antimicrobial exhibiting concentration dependent bacterial killing. A high dose ofgentamicin (10 mg kg(-1)) is required to reach sufficient concentrations in specific fluids as cerebrospinal fluid and to be effective on antibiotics resistant bacteria as well as treatment of acute and dangerous illness. Using a rat model, the renal toxicity and oxidative stress of administering gentamicin (10 mg kg(-1) daily for 7 days) either in a single dose or divided into 2 doses was investigated. The safety of dose regimens was assessed through oxidant-antioxidant parameters as well as renal function tests. Typical renal damage and high oxidative stress were evident in the control group receiving 100 mg kg(-1) gentamicin daily for 7 days. This was verified by high serum urea, uric acid, creatinine as well as increase in the levels of oxidative stress biomarkers as malondialdehyde, NO, total antioxidant capacity and decrease in reduced glutathione level. At any of the used regimen, 10 mg kg(-1) gentamicin did not provide high compromise for renal functions nor significantly increased the oxidative stress and tissue damage. Based on microscopic lesions scores and biochemical analysis, there were no significant differences between single or two divided dosages of gentamicin at dose rate of 10 mg kg(-1) day(-1). Further studies are required for applications in other animals of human subjects.