TOXICOLOGICAL AND HISTOLOGICAL EFFECTS OF SILVER NANOPARTICLES ON THE LUNG OF ADULT MALE ALBINO RAT AND PROTECTIVE ROLE OF GREEN TEA EXTRACT

Abstract

Silver nanoparticles (AgNPs) are incorporated into a large number of consumer and medical products. AgNPs has been reported as the materials with high toxicity especially after the systemic uses. The present work aimed to evaluate the toxic effects of two different doses 0.5, 10 mg/kg of AgNPs (35±8.5nm) on the lung of adult male albino rat following 30 days oral administration and also to assess the protective role of green tea extract (GT). Sixty rats were classified into six groups (ten rats/ group); Group1:(control group) allowed distillate water, Group2: Rats were given GT at a concentration of 1.5%, Group3: AgNPs treated rats (0.5mg/kg/day), Group4: AgNPs treated rats (0.5mg/kg/day)–co administered GT, Group5: AgNPs treated rats (10mg/kg/day), and Group6: AgNPs (10mg/kg/ day)–co administered GT. This aim was undertaken through adopting certain parameters including, animal observation, changes in body weight, and biochemical studies for antioxidant enzymes {super oxide dismutase (SOD) and catalase (CAT)}. Absolute and relative lung weights have been carried as well. Histological examination of lung tissue using different stains; HE whereas a nonsignificant increase in GT group and groups treated with GT+ AgNPs at the end of experiment as compared to the initial value. AgNPs significantly decreased (CAT) while, increased SOD level. GT significantly increased relative lung weight while, a nonsignificant increase in AgNPs groups as compared to control. Histological examination of lung tissue revealed histological alterations in groups treated with AgNPs which were more pronounced in high dose (10mg) including; thickening of the alveolar wall, destruction of the alveoli, dilated alveoli, mononuclear cellular infiltration associated with marked collagen deposition and weak immunoexpression for surfactant protein B. Coadministration of GT with AgNPs caused significant amelioration of biochemical, histological and immunohistochemical changes induced by AgNPs. Conclusion: Silver nanoparticles caused oxidative damage, biochemical changes and histological alterations in the lung of male rat. This study demonstrates the benefits of green tea as it reduces oxidative damage by virtue of its antioxidant properties thus improving the structural integrity of lung tissue and eventually alleviates the histological changes as well as the biochemical perturbations.