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Abstract The kidneys are the primary organ for eliminating waste products of the body, and eliminate most toxins and other foreign substances that are either produced by the body or ingested, such as pesticides, drugs, and food additives (Guyton and Hall, 2016). Zinc oxide nanoparticles (ZnO NPs) are widely used in various applications including cosmetics, paints, as drug carriers also in medical materials (Dufour et al., 2006). These nanoparticles can also be used in environmental industries due to their good absorptive and photocatalytic properties for elimination or degradation of pollutants in water or air (Qiang, 2001). Exposure to ZnO NPs has potential toxicity, including cytotoxic, genotoxic, and proinflammatory effects. ZnO NPs induce oxidative stress through reactive oxygen species (ROS). High dose of ZnO NPs cause nephrotoxicity and alternation in kidney metabolism in experimental animals (Sharma et al., 2012). ZnO NPs may exhibit unpredictable genotoxic properties. ZnO NPs induces toxicity in various mammalian cells leading to potent DNA damage. DNA damage may be caused by induction of oxidative stress and inflammatory responses. ZnO NPs may cross cellular membranes and access the nucleus, and DNA interaction resulted in its damage (Brown et al., 2006). Our study was performed to study histological ,histochemicals and genotoxicty of ZnO NPs on adult male rabbits. The present study was carried out on 15 adult male rabbits ,weighing from 1.5 to 2 kg. The animals were divided into three groups randomly, 5 animals each.group Ι: kept without treatment as control group. group Π: Summary and conclusion 74 were received ZnO NPs intraperitonial injections in a dose 100ml/kg(0.4 cm of prepared solution) once daily for 14 days. group ΠΙ: were received ZnO NPs intraperitonial injections in a dose 250ml/kg (1cm of prepared solution) once daily for 14 days. The rabbits were sacrificed on the fifteenth day of the experiment after being anaesthetized by ether. Kidneys and both femurs of each animal were obtained. Kidney samples were examined by light microscope to study histological and histochemical effects of ZnO NPs. Bone marrow samples were analyzed by flowcytometery and DNA fragmentation assay. Our results revealed that 1-ZnO NPs caused histological and histochemical changes especially in high dose treated group. There were destruction of renal tubules in form of vacuolation of cytoplasm, dense nucleus and loss of brush border of PCT. There was prominent intratubular PAS positive deposition. There were infiltrations of inflammatory cells in between tubules. Also there were intraglomerular congestions. 2-In thise study there were prominent decrease in intensity of PAS stain in the cytoplasm and loss of brush border especially in high dose group. Also there were prominent fibrosis intra glomerular and in between tubules in treated groups. 3- In our study we found an increase in the apoptotic cells of bone marrow samples from 4.49% in control group to 7.39% in low dose treated group and increase to 19.74 % in high dose treated group by using propodium iodid flowcytometric kits. 4-In our study we used Anixin V FITC,it was found that, in control group there were 1.92% late appoptic cells, 2.03% early appoptic and only Summary and conclusion 75 0.54% was necrotic. In group II, we found that late appoptic cells were 3.59%, early appoptic cells were 2.84% and 0.98% were necrotic.In groupIII, we found that late appoptic cells were 3.59%, early appoptic cells were 2.84% and necrotic cells were 0.96%.these indicate ZnO NPs mainly induce apoptosis not necrosis. 5- In the present study we examined DNA fragmentation by agarose gel electrophoresis. High dose treatment led to significant increase in the number of cells undergoing apoptosis as compared with control and other low dose group. Further, this group showed intact DNA with no ladder formation. On the other hand, administration of high dose presented a prominent laddering/ DNA fragmentation. Concolusion ZnO NPs causes histolopathological changes of the kidney through oxidative stress and has genotoxic effect on bone marrow.These may give us more information on hazards of ZnO NPs on human health. |