Oral application of carbon nanofibers in rats increases blood concentration of IL6 and IL10 and decreases locomotor activity

- Carbon nanofibers induce immune activation indicated by elevated IL-6 levels.
- The stimulated proinflammatory response counteracted by a pronounced increase in IL-10.
- Cytokines have key regulatory functions on behavioral alterations.
- The chronic oral exposure to carbon nanofibers reduce locomotor activity of rats.

Carbon nanofibers (CNF) are versatile nanomaterials that are widely used in various fields of science and technology. As a consequence, animals as well as humans may be exposed to such compounds via different routes. We hypothesized that oral intake of CNF will lead to an inflammatory reaction and consequently induce behavioral impairments. To address this issue, rats were fed with 500 mg/kg CNF for 14 days and their locomotor activity, emotional status and cognition were quantified by testing the animals in an open field set-up, elevated plus maze and in the universal problem solving box which provides information about motivation and cognition. The behavioral tests were performed 3 times within 10 days. At the end of the experiment, blood samples were collected and the plasma concentrations of IL-6, IL-8, IL-1β, IL-10 and IL-18 were measured. Our results demonstrated an inflammatory reaction determined by a significantly elevated IL-6 concentration. This, however, was counteracted by an even more pronounced increase in IL-10. The behavioral effects were restricted mainly to a decrease in locomotor activity which was significant in the open field test, as well as the elevated plus maze. Other parameters indicative of cognitive performance were not influenced and also the emotional status was largely unaffected. In conclusion, our results revealed that oral intake of 500 mg/kg CNF induced some adverse effects, which, however, can be still partially compensated by the organism.

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