Antagonistic Effect of Laver, Pyropia yezonensis and P. haitanensis , on Subchronic Lead Poisoning in Rats

Lead, one of the most harmful heavy metals, can cause various hazardous effects on living organisms. This study was undertaken to evaluate the antagonistic and protective effects of two economically important laver species, Pyropia yezoensis and P. haitanensis , against subchronic lead poisoning in rats by a 30-day feeding test. Sixty-four healthy Wistar rats were randomly divided into eight groups with eight rats (4♂ + 4♀) per group, among which, one group was served as the control, the others were respectively treated with lead acetate (5 mg/kg b w), and a combination of lead acetate and P. yezoensis or P. haitanensis at different dosages. Weight gain of rats was observed and recorded. Changes in antioxidant indexes, and liver and renal function markers were determined to evaluate the antagonistic effect. Lead content in rats was determined to investigate lead excretion effect of laver. The results showed that exposure to lead caused lead accumulation in kidney and liver, thus leading to significant oxidative damage and impaired liver and renal function compared to the control group. The co-treatment of laver slightly increased body weight compared to the lead-treated group. The co-administration of laver restored liver and renal function of rats by preventing the increment in the activities of alanine transaminase (ALT), alkaline phosphatase (ALP), and aspartate transaminase (AST), and the levels of blood urea nitrogen (BUN) and creatinine (Cr). The increasing of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities, and lowering of the enhanced malondialdehyde (MDA) contents of rats were observed in the laver co-treated groups, which indicated that laver enhanced the antioxidative capacity of rats. The laver also enhanced lead content in feces and reduced it in liver and kidney. The results indicated that P. yezoensis and P. haitanensis could maintain or promote the normal physiological and biochemical function of lead-induced subchronic poisoning of rats, probably owing to their enhancements of antioxidant capacity and lead excretion.