Neuroprotective effect of green tea extract aginst lead toxicity in rats

الملخص EN

The toxicity of lead (Pb) is of concern to public health due to its persistence in the environment.

Brain is one of the major target organs where severe neurological alternations may be triggered after exposure.

Pb could disrupt prooxidant/antioxidant balance of tissue which leads to physiological dysfunction.

Green tea extract (GTE) is antioxidant, free radicals scavenger and has chelating property.

This study was conducted to investigate effect of GTE on reducing Pb toxicity of the brain of male rats.

Four groups of male rats (each 15 rats) were utilized as following: control, GTE-group (1.5% w/v), Pb-group (0.4% lead acetate in distilled water), Pb + GTE-group.

Rats received GTE and/or lead orally in drinking water for 6 weeks.

Levels of oxidant and antioxidant [lipid peroxides (LPO), nitric oxides (NO), total antioxidant capacity (TAC), glutathione (GSH), glutathione S-transferase (GST), superoxide dismutase.

(SOD)] were measured using colorimetric methods.

Pb," concentration in brain tissue was measured by atomic absorption; spectrometer.

Histological sections of brain tissues were prepared and examined using the routine pathological technique.

Pb concentrations in Pb-treated group were higher in brain tissue than controls.

In Pb-group, levels of LPO were higher while, NO and GSH were lower in plasma than controls.

Plasma level of TAC was lower in Pb- treated group than -control.

Levels of SOD; GST in tissue were lower in Pb-exposed rats versus control.

GTE co-administrated with Pb appeared more effective *? in reduction of Pb contents, LPO and increase antioxidant status in plasma and brain tissue comparing to Pb-group.

Also, severe destructive changes were observed in the" brain tissue, treated with Pb alone/ represented by meningitis, neuronal degeneration, cerebral infarction, interphase encephalitis and purkinje cell layer degeneration and necrosis in the cerebellum.

While the cases treated with lead and GTE, showed' marked improvement in the cellular structure of the brain, represented by5 vacuolated neurons and absence of necrosis, of the cerebellar purkinje' cell layer.

The data from this study suggest that lead can induce toxicity > by interfering with delicate balance between pro- and antioxidants.

The \ treatment of rats with GTE combined with Pb could enhance antioxidant /detoxification system which consequently reduced oxidative stress and Pb burden m the train thus potentially reducing Pb tS and tissue damage.

Running title: Lead toxicity: Effect of Green Tea Extract on Oxidative Stress in Rat Brain.