Abstract

Nesrine S. El-Sayed* and Sherine M. Rizk

The possible protective potentials of quercetin (50 mg/kg, p.o.), green tea extract (1 mg/kg, p.o.) malt extract (625 mg/kg, p.o.) and deprenyl (10 mg/kg, i.p.) against paraquat (PQ) -induced lung injury in rats were examined. PQ was administered twice a week (20 mg/kg, i.p.) with or without daily pretreatment with any of the chosen agents for 3 successive weeks. Changes in the enzymatic activities of myeloperoxidase (MPO), superoxide dismutase (SOD) and lactate dehydrogenase (LDH) as well as reduced glutathione (GSH), protein thiols (Pr-SHs) and nitric oxide (NO) contents of the lungs were determined. In addition, estimation of lung content of thiobarbituric acid reactive substances (TBARS) measured as malondialdehyde. Moreover, histopathological examination of the lung tissue was performed. On the biochemical level, PQ provoked remarkable lung damage noted by elevation of neutrophils MPO activity accompanied by decreased activities of cytosolic SOD and LDH, depletion of GSH and Pr-SHs contents as well as increased production of NO and TBARS. Furthermore, histopathological examination revealed marked edema, subpleural hemorrhage, acute inflammation and lymphocytic infiltration. Treatment significantly protected against most of PQ-induced lung biochemical and histopathological changes. It could be concluded that quercetin, green tea, malt extract and deprenyl offered remarkable protection against PQ-induced lung injury.