Oxidative Stress and Antioxidant Response in Gentamicin-Treated Rats – Role of Green Tea Extract on Renal Malondialdehyde (MDA) Levels

Open Access

Abstract

Background: Gentamicin is an effective aminoglycoside antibiotic, but its use is limited by nephrotoxicity caused by oxidative stress. Malondialdehyde (MDA) reflects oxidative damage, while enzymes like SOD, CAT, GPx, and GSH indicate antioxidant status. Green tea extract (GTE), rich in epigallocatechin-3-gallate (EGCG), possesses potent antioxidant properties that may protect against such injury. This study evaluates the protective effect of GTE on renal oxidative stress by measuring MDA and antioxidant enzyme activity in gentamicin-treated rats. Methods & Materials: This experimental study was conducted in the Department of Physiology, Sir Salimullah Medical College, Dhaka (July 2019–June 2020) on 30 healthy male Long Evans rats (90–120 days old, 150–200 g). Renal oxidative stress markers (MDA) and antioxidant enzymes (SOD, CAT, GPx, GSH) were measured by spectrophotometric methods, while serum creatinine, urea, and BUN were assessed using enzymatic colorimetric assays. Kidney tissues were examined histologically after H&E staining. Data were analyzed using SPSS v26, with p ≤0.05 considered statistically significant. Results: Most rats showed elevated oxidative stress, with over two-thirds having high MDA levels and reduced antioxidant enzyme activity. Strong negative correlations between MDA and antioxidants confirmed oxidative–antioxidant imbalance. Histological analysis revealed frequent tubular damage and congestion, indicating significant renal injury and oxidative dominance in gentamicin-treated rats. Conclusion: Gentamicin caused significant oxidative stress and kidney damage in rats, while green tea extract effectively reduced lipid peroxidation and restored antioxidant defenses. These results highlight the protective role of green tea polyphenols against drug-induced nephrotoxicity and suggest their potential as a safe, natural adjunct to minimize kidney injury during gentamicin therapy.