Protective Effects of Alpha-lipoic Acid and Melatonin against Cadmium-induced Oxidative Stress in Erythrocytes of Rats

Cadmium (Cd) is a well-known human carcinogen and a potent nephrotoxin. The protective effects of alpha-lipoic acid and melatonin against cadmium (Cd) induced oxidative stress to erythrocytes in rats were evaluated. One hundred male albino rats were divided into five groups containing 20 rats each. Group I: (control) administered distilled water. Group II :( Cadmium exposed group) received cadmium chloride (4.4 mg/kg body weight of 1/20th of LD50 / day) orally for 10 weeks. Group III :( Cadmium +alpha-lipoic acid) received cadmium chloride (4.4 mg/kg body weight) and treated daily with alphalipoic acid (54 mg/kg body weight/ i.p). Group IV :( Cadmium +Melatonin) received cadmium chloride (4.4 mg/kg body weight) and treated daily with melatonin (10 mg/kg body weight/orally). Group V :( Cadmium +alpha-lipoic acid and melatonin). Urea and creatinine concentrations were determined in plasma. However, erythrocyte hemolysate were processed for the determination of L-Malondialdhyde (LMDA), catalase (CAT), superoxide dismutase (SOD), GlutathioneS-transferase (GST) and reduced Glutathione (GSH) in addition to erythrocytes Glucose -6-phosphate dehydrogenase (G-6-PDH) activity. Also, kidney specimens were used for cadmium residues determination. The obtained results revealed that, a significant increase in plasma urea, creatinine concentrations and erythrocyte L-MDA level, SOD activity in addition to kidney cadmium residue concentrations were observed in cadmium intoxicated rats. However, administration of alpha-lipoic acid, melatonin and their combination exhibited a significant decreased in all mentioned parameters. On the other hand, a significant decreased in erythrocyte CAT, GST and G-6-PDH activities, GSH concentration were observed in cadmium intoxicated rats. Meanwhile, treatment with alpha-lipoic acid and melatonin resulted in significant increase in all mentioned parameters. It could be concluded that, the potential protective effect of alpha-lipoic acid and melatonin as a powerful agents and may be useful as an antioxidants in combating free radical-induced oxidative stress and tissue injury that is a result of cadmium toxicity.