In Vitro Interactions of TiO Nanoparticles with Earthworm Coelomocytes: Immunotoxicity Assessment.

Titanium dioxide nanoparticles (TiO NPs) are manufactured worldwide. Once they arrive in the soil environment, they can endanger living organisms. Hence, monitoring and assessing the effects of these nanoparticles is required. We focus on the earthworm immune cells exposed to sublethal concentrations of TiO NPs (1, 10, and 100 µg/mL) for 2, 6, and 24 h. TiO NPs at all concentrations did not affect cell viability. Further, TiO NPs did not cause changes in reactive oxygen species (ROS) production, malondialdehyde (MDA) production, and phagocytic activity. Similarly, they did not elicit DNA damage. Overall, we did not detect any toxic effects of TiO NPs at the cellular level. At the gene expression level, slight changes were detected. Metallothionein, fetidin/lysenin, lumbricin and MEK kinase I were upregulated in coelomocytes after exposure to 10 µg/mL TiO NPs for 6 h. Antioxidant enzyme expression was similar in exposed and control cells. TiO NPs were detected on coelomocyte membranes. However, our results do not show any strong effects of these nanoparticles on coelomocytes at both the cellular and molecular levels.