Protective effect of green tea on lead-induced oxidative damage in rat’s blood and brain tissue homogenates

Abstract

Recent studies have shown that lead (Pb) could disrupt tissue prooxidant/antioxidant balance which lead to physiological dysfunction. Natural antioxidants are particularly useful in such situation. Current study was designed to investigate efficacy of green tea extract (GTE), on oxidative status in brain tissue and blood caused by chronic oral Pb administration in rats. Four groups of adult male rats (each 15 rats) were utilized: control group; GTE-group (oral 1.5% w/v GTE for 6 weeks); Pb-group (oral 0.4% lead acetate for 6 weeks), and Pb+GTE-group (1.5% GTE and 0.4% lead acetate for 6 weeks). Levels of prooxidant/antioxidant parameters [lipid peroxides (LPO), nitric oxides (NO), total antioxidant capacity (TAC), glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD)] in plasma, erythrocytes, and brain tissue homogenate were measured using colorimetric methods. Pb concentrations in whole blood and brain tissue homogenate were measured by atomic absorption. In Pb-group, levels of LPO were higher while NO and GSH were lower in plasma, erythrocytes, and brain tissue than controls. TAC in plasma, SOD in erythrocytes, and GST in brain tissue homogenate were lower in Pb-group versus control. GTE co-administrated with Pb-reduced Pb contents, increased antioxidant status than Pb-group. In erythrocytes, Pb correlated positively with LPO and negatively with NO, GSH, SOD, and Hb. In brain tissue homogenate, Pb correlated positively with LPO and negatively with GSH. This study suggests that lead induce toxicity by interfering balance between prooxidant/antioxidant. Treatment of rats with GTE combined with Pb enhances antioxidant/ detoxification system which reduced oxidative stress. These observations suggest that GTE is a potential complementary agent in treatment of chronic lead intoxication.

Cardio protective effects of Nigella sativa oil on lead induced cardio toxicity: Anti inflammatory and antioxidant mechanism

“…These results are consistent with the findings of Badalzahed et al (2008). The increased heart rate in Pb group was probably due to observed central sympathetic nervous system hyperactivity, reduced baroreflex sensitivity and vagal hypotonia in rats treated chronically with lead (Carmignani et al, 2000), while NSO treatment decreased the heart rate to control level and reduced the ST segment significantly; this indicates that NSO has heart rate-reducing effect, which may occur by activating cholinergic mechanisms (El-Tahir et al,1993;Hamed et al, 2010). …”

Elucidation of mechanisms underlying the protective effects of olive leaf extract against lead-induced neurotoxicity in Wistar rats

“…Recently, Hamed et al (2010) reported that Pb induced toxicity in different brain areas by interfering on the balance between prooxidant/antioxidant. The authors demonstrated that Pb induced LPO products accumulation, decreased glutathione pool and inhibited antioxidant enzyme activities, such as GST and superoxide dismutase (SOD).…”

Oral Administration of Tocotrienol Ameliorates Lead-Induced Toxicity in the Rat Brain

“…In relation to brain lead levels, results from the present study seemed to correlate with several studies reported to date. A similarly-designed study investigated the effect of green tea leaf extract (GTE) on animals treated with lead acetate 0.4% w/v for six weeks has reported significant decreased in brain and blood levels in the experimantal rats treated with antioxidant compared to non-treated group (Hamed et al 2010). Additionally, the study showed positive correlation between brain lead levels and lipid peroxides (LPO) and negative correlations with glutathione (GSH).…”

“…The brain lead concentration was analyzed by atomic absorption spectrophotometer (Perkin-Elmer, United States of America) at 283.3 nm based on a described method with slight modifications (Hamed et al 2010). Brain hemisphere was weighed (1 gm) and placed into a polypropylene tube.…”

“…There is increase in evidence that chronic lead exposure plays an important role in the disruption of prooxidant: antioxidant balance in the brain tissue and alters brain histology which leads to physiological dysfunction (Bokara et al 2008;Hamed et al 2010). Oxidative stress occurs in the plasma and brain tissue in lead-exposed rats as evidenced by decreased important intracellular antioxidant enzymes and increased lipid peroxidation products (Xia et al 2010).…”