Background: Gentamicin (GM) is one the aminoglycoside antibiotics which isroutinelyused to treatinfections gram-negative, either alone or insynergistic withbeta-lactamantibioticsused. However, frequent useleads toserious side effectssuch asrenal toxicity, ototoxicity. Coenzyme Q₁₀ has antioxidant, anti-inflammatory and vasodilatory properties. According to these properties of Coenzyme Q₁₀ and tissue damage mechanism in GM induced-nephrotoxicity, in this study, the effects of these two substances for the co-treatment and post -treatment on renal injury induced by gentamicin were investigated.

Materials and Methods:  Experiments has been done on 77 male Wistar rats in weight range of 200 to 250 g. Animals were divided randomly into 5 groups of 7 numbers. Renal nephrotoxicity induced by i.p injection of gentamicin (100mg/kg) Therapeutic effect of coenzyme Q₁₀ (10mg/kg)in the two protocols co-treatment  and post-treatmentwas investigated.The animals after the last injectionon the ninth day of co-treatment andthe seventeenth day of post-treatmentwere placed into individual metabolic cages so as to collection urine and urine volume was measured gravimetrically. Afteranesthesia, systolic blood pressure and renal blood flow was measured. Then blood sampling was done. Amount of urea, creatinin, sodium, potassium and osmolarity was measured in plasma and urine samples. Left kidney, for doing histological experiments in 10% buffered formaldehyde and right kidney for biochemical experiments in fluid nitrogen was preserved.

Results: Co-treatment with Coenzyme Q10 significantly decreased fractional excretion of sodium (6.37±1.33 %; p<0.001) and decreased fractional excretion of potassium(219.14±83.8 %; p<0.001) MDA levels (2.13 ±0.24µmol/gkw; p<0.001), and significantly increased renal blood flow (6.38 ±0.1ml/min: p<0.01) and FRAP levels (24.44±0.42mmol/gkw; p<0.001). Post-treatment with coenzyme Q10 significantly decreased fractional excretion of sodium (3.58 ±0.57 %; p<0.001), potassium (111.77±29.4%; p<0.001) and MDA levels (3.08 ±0.12µmol/gkw; p<0.001) and significantly increased renal blood flow (6.74±0.15ml/min: p<0.001) and FRAP levels (24.34±0.75mmol/gkw; p<0.001) that is reduced by gentamicin.

Conclusion: According to the results, this study showed thatpost- treatment with coenzyme Q₁₀more protective effect on the kidney tissue andAnda greater increase inantioxidant defensecreated.