tannins and Lead-Poisoning

Cadmium (Cd) and lead (Pb) are toxic elements that accumulate to the largest extent in bones. Rats were used to investigate whether tannic acid (TA; 0.5%, 1.0%, 1.5%. 2.0%, or 2.5%) would have a protective effect on the structure and properties of bones in the case of exposure to Cd and Pb (diet: 7 mg Cd/kg and 50 mg Pb/kg) for 6 weeks. The effects of administration of TA in Cd- and Pb-poisoned rats on bone characteristics and the morphology of articular and growth cartilages were determined. All the rats administered Cd and Pb had an enhanced Cd and Pb concentration in blood plasma and bone and reduced bone Ca content irrespective of the TA administration. Cd and Pb alone reduced the mechanical endurance and histomorphometric parameters of trabecular bone and the thickness of the growth plate and articular cartilage. Tannic acid improved cancellous bone parameters in the rat exposed to Cd and Pb. A diet rich in TA improved articular cartilage constituents in heavy metal-poisoned rats. These results suggest that alimentary TA supplementation can counteract in a dose-dependent manner some of the destructive changes evoked by Cd and Pb possibly by reducing the exposure.

Topics: Animals; Biomechanical Phenomena; Bone and Bones; Bone Density; Bone Density Conservation Agents; Cadmium; Cadmium Poisoning; Calcium; Cancellous Bone; Cartilage, Articular; Dose-Response Relationship, Drug; Growth Plate; Lead; Lead Poisoning; Male; Osteomalacia; Osteoporosis; Protective Agents; Random Allocation; Rats, Wistar; Tannins; Toxicokinetics

Lead toxicity is a major public health concern. This study was designed to investigate the effects of oral administration of tannic acid (TA) on lead acetate (LA)-induced oxidative stress in rat liver and kidney. Rats were treated with 50 mg/kg body weight of TA against LA-induced oxidative stress 3 times/week for 2 weeks. At a rate of 50 mg/kg of body weight, LA was given intraperitoneally 3 times/week for 2 weeks. Results show significantly elevated levels of oxidative stress markers observed in LA-treated rats, whereas significant depletion in the activity of nonenzymatic and enzymatic antioxidants as well as histological changes were observed in LA-treated rat liver and kidney. TA treatment significantly attenuated the altered levels of oxidative stress biomarkers for nonenzymatic and enzymatic antioxidants. We demonstrated that TA exhibits potent antioxidant and protected against oxidative damage in rat liver and kidney induced by LA treatment. These findings were further supported by histopathological findings in liver and kidney showing that TA protected tissue from the deleterious effects of LA treatment. These outcomes suggest that the consumption of TA may confer a protective effect against lead intoxication through its antioxidative effect.

Topics: Animals; Antioxidants; Environmental Pollutants; Kidney; Lead Poisoning; Liver; Male; Organometallic Compounds; Oxidative Stress; Rats; Rats, Wistar; Tannins

Lead (Pb) is known to disrupt the pro-oxidant/antioxidant balance of tissues leading to biochemical and physiological dysfunction. The present study was designed to investigate the effect of tannic acid on some biochemical parameters in Swiss albino mice exposed to lead acetate. The levels of thiobarbaturic acid-reactive substances (TBARS) as an index of lipid peroxidation, nitric oxide (NO), and serum lead (Pb) were significantly increased following intragastric administration of 50 micromole lead acetate/kg body weight three times a week, every other day for three weeks, compared to the corresponding control values. On the other hand, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione-S-transferase (GST) and glutathione content (GSH) and serum copper (Cu) and zinc (Zn) were significantly diminished relative to the control values. The administration of 20 mg tannic acid/kg body weight three times a week every other day for three weeks, enhanced the endogenous antioxidant capacity of the cells by increasing the activities of antioxidant enzymes (SOD, CAT, GSH-R, GST), GSH content and serum Cu and Zn levels. Compared to the lead acetate-exposed group, the levels of TBARS, NO and Pb were decreased in the lead acetate exposed group treated with tannic acid. These results afford evidence supporting the hypothesis that lead induces oxidative stress in hepatic cells. Moreover, tannic acid has a potential in sustaining global antioxidant effect in hepatic cells leading to decreased oxidative stress and cellular damage initiated through free radical production by lead acetate.

Topics: Animals; Antioxidants; Lead Poisoning; Lipid Peroxidation; Liver; Mice; Oxidative Stress; Tannins; Thiobarbituric Acid Reactive Substances; Trace Elements

Topics: Animals; Female; Growth; Hydrolyzable Tannins; Lead; Lead Poisoning; Mice; Reproduction; Tannins