Toxicological evaluation of copper oxide nanoparticles following their intraperitoneal injection to Wistar rats.

Background: Copper oxide (Cu₂O) nanoparticles (CO NPs) are in extensive use during our everyday life as antimicrobial agent, lubricant, in manufacturing electrodes of lithium ion batteries as well as for photo catalytic degradation of organic pollutants. Due to extensive and diverse use Cu₂O NPs, they are likely to accumulate in the environment and to affect the live forms. Present investigation was aimed to report the biocompatibility of CO NPs in Wistar rats in sex specific manner. CO NPs, having average diameter of 14.06 nm, were synthesized by co-precipitation method and scanning electron microscopy and X ray diffraction were used for their characterization.

Methods: For 14 consecutive days, Wistar rats (6 weeks old) of both sexes were intraperitoneally injected with 10 mg/mL saline/Kg body weight of CO NPs, while the control groups intraperitoneally received saline solution for same duration. Behavioral tests (open field and novel object recognition), complete blood count, selected biomarkers of oxidative stress and Copper concentration in brain and liver were determined in all subjects.

Results: High mortality rates [male 40% and female 60%] were observed in rats exposed to CO NPs. A sever decrease in body weight was also observed in both male and female rats exposed to CO NPs. Female rats treated with CO NPs spent significantly more time with novel object as compared to control [P = 0.05] during second trial of novel object test. CO NPs treated female rats had higher mean corpuscular hemoglobin [P < 0.001] levels and Copper concentration in liver [P = 0.04] than control. Male rats exposed to CO NPs had significantly higher mean corpuscular volume [P = 0.02] and superoxide dismutase [SOD] [P = 0.04] in lungs than their control group. All other studied parameters non significantly varied upon comparison between CO NPs treated and untreated rats of both sex.

Conclusion: In conclusion, we are reporting that intraperitoneal injections of CO NPs for 14 days can disturb complete blood count and biomarkers of oxidative stress in lungs of Wistar rats.