Abstract
Background:
Green tea (GT), which is rich in polyphenolic compounds, has an extensive array of proactive preventive and therapeutic properties for the mitigation of various diseases, including acute kidney damage. This study hypothesized that GT attenuates gentamicin-induced renal damage by decreasing the levels of inflammatory biomarkers and exerting antioxidant properties.

Aim:
This experiment was designed to investigate the effects of gentamicin on kidney functions and to determine whether GT extract prevents or minimizes the adverse effects of gentamicin in male Sprague-Dawley rats.

Methods:
Five groups were formed: a control (untreated) group and four experimental groups. For two weeks, the control group received distilled water (DW). In the first experimental group (T1), rats orally received GT extract (20 µg/g body weight) for two weeks. In the second group (T2), gentamicin (100 mg/kg body weight) was injected intraperitoneally for 1 week. In the third group (T3), rats were intraperitoneally injected with gentamicin for a week; then, an oral administration of GT extract. In the last group (T4), an intraperitoneal injection of gentamicin was administered, followed by an oral administration of GT extract for 2 weeks. Blood and kidney tissues were collected at the end of the treatment for biochemical and histological examinations.

Results:
The administration of gentamicin induced a decline in body weight and increases in the levels of inflammatory markers (kidney injury molecule I, tumor necrosis factor-alpha, and interleukin-6), urea, and creatinine, which are indicative of renal damage. Histopathological examination revealed extensive renal tissue damage. However, concurrent administration of gentamicin and GT diminished these parameters by decreasing the malondialdehyde concentration and improving the activity of antioxidant enzymes (glutathione peroxidase and superoxide dismutase). Furthermore, gentamicin injections caused nephrotoxicity, as evidenced by a reduction in body weight and higher levels of urea, creatinine, and inflammatory markers.

Conclusion:
GT mitigated the effects of gentamicin by improving the activity of antioxidant enzymes, resulting in a reduction in oxidative stress and minimization of inflammation. These findings suggest a potential complementary role for GT extract in the minimization of gentamicin-induced nephrotoxicity.

Key words: Green tea, Inflammatory markers, Renal function