Abstract
Metal oxide nanoparticles have wide applications, which have elevated serious alarms about their impacts on the environment. Therefore, we investigated the potential adsorptive capacity of rice husk toward Fe2O3 and Al2O3 nanoparticles to reduce their genotoxic effects. Fish were subjected to 10 mg/l of Fe2O3 and Al2O3 nanoparticles in single and combined doses with and without rice husk water treatment for 7 days. The genotoxic effects were evaluated using the micronucleus test in the peripheral blood and comet assay in liver tissues. Significant elevation of micronuclei induction in addition to eight nuclear and cytoplasmic abnormalities (P < 0.05) was observed in all fish groups compared to the control groups. Fish that exposed to Fe2O3 nanoparticle showed the maximum induction of all recorded anomalies. Moreover, two indices of DNA damage were evaluated by the comet assay (comet score and % tail DNA) in liver tissues. The scoring of comet cells indicated that the highest frequencies of stage 0 (undamaged DNA) were in control and Al2O3 exposed groups, while stage 4 (extensive DNA damage) was significantly elevated in Fe2O3 exposed fish. The % of DNA damage was maximized in the Fe2O3 nanoparticles exposed fish and minimized in Al2O3 nanoparticles exposed fish. Based on the frequencies of nuclear anomalies, degree, and percentage of DNA damage, all rice husk treated groups showed a marked reduction in the genotoxic damage compared with untreated groups. Finally, both nanoparticles showed genotoxic potential and the rice husk had an efficient absorptive capacity for both of them individually or combined.