Nephrotoxicity is recognized as a serious disorder affected by chronic cadmium exposure. Imbalance between radical generation and elimination is considered a critical factor involved in the initiation and progression of renal injury caused by this heavy metal. The present study investigated the possible protection by catechin, a natural phenolic antioxidant, against cadmium nephrotoxicity and elucidated its potential mechanism. Male Wistar rats were assigned to receive vehicle, cadmium (CdCl2 2 mg/kg, i.p.) and cadmium plus catechin (25, 50, and 100 mg/kg, orally, respectively). After 4 weeks of treatment, rats exposed to cadmium demonstrated a marked rise in blood urea nitrogen and creatinine, a fall in creatinine clearance, and renal pathologies like severe tubular damage, apoptosis, and abnormal mitochondrial structure. Significant increases in malondialdehyde, nitric oxide, and tumor necrosis factor-alpha, while reductions in antioxidant thiols, superoxide dismutase, and catalase, were also detected in the kidney tissues of cadmium-intoxicated rats. These alterations were associated with mitochondrial dysfunction as supported by an increase in mitochondrial reactive oxygen species production and a decline in mitochondrial membrane potential. Treatment with catechin significantly attenuated all the changes caused by cadmium. These findings suggest that catechin effectively protects the kidney against toxic effect of cadmium, presumably through its antioxidant, anti-inflammation, and mitochondrial protection. The study outcomes not only add evidence to reinforce the medical benefits of catechin but also, most importantly, give rise to a prospect of developing renal preventive strategy for individuals who are at risk of cadmium contamination by means of catechin supplementation.
Keywords: Cadmium; Catechin; Inflammation; Kidney; Mitochondria; Oxidative stress.