Titanium dioxide exposure induces acute eosinophilic lung inflammation in rabbits

Titanium dioxide nanoparticles exaggerate respiratory syncytial virus-induced airway epithelial barrier dysfunction

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in children worldwide. While most develop a mild, self-limiting illness, some develop severe acute lower respiratory infection and persistent airway disease. Exposure to ambient particulate matter has been linked to asthma, bronchitis, and viral infection in multiple epidemiological studies. We hypothesized that coexposure to nanoparticles worsens RSV-induced airway epithelial barrier dysfunction. Bronchial epithelial cells were incubated with titanium dioxide nanoparticles (TiO2-NP) or a combination of TiO2-NP and RSV. Structure and function of epithelial cell barrier were analyzed. Viral titer and the role of reactive oxygen species (ROS) generation were evaluated. In vivo, mice were intranasally incubated with TiO2-NP, RSV, or a combination. Lungs and bronchoalveolar lavage (BAL) fluid were harvested for analysis of airway inflammation and apical junctional complex (AJC) disruption. RSV-induced AJC disruption was amplified by TiO2-NP. Nanoparticle exposure increased viral infection in epithelial cells. TiO2-NP induced generation of ROS, and pretreatment with antioxidant, N-acetylcysteine, reversed said barrier dysfunction. In vivo, RSV-induced injury and AJC disruption were augmented in the lungs of mice given TiO2-NP. Airway inflammation was exacerbated, as evidenced by increased white blood cell infiltration into the BAL, along with exaggeration of peribronchial inflammation and AJC disruption. These data demonstrate that TiO2-NP exposure exacerbates RSV-induced AJC dysfunction and increases inflammation by mechanisms involving generation of ROS. Further studies are required to determine whether NP exposure plays a role in the health disparities of asthma and other lung diseases, and why some children experience more severe airway disease with RSV infection.

The long-term oral exposure to titanium dioxide impaired immune functions and triggered cytotoxic and genotoxic impacts in rats

BACKGROUND

Titanium dioxide "TiO₂, E171″ is a widely used food additive that exists in various everyday food products all over the world together with vast applications in cosmetics and industry. However, many toxicological aspects particularly following oral exposure still unclear.

METHODS

Hence, this study was planned to examine the effect of oral exposure of male Wistar rats to two doses of TiO₂ (20 or 40 mg/kg b.wt.) through oral gavage once daily for 90 consecutive days on the blood components, immunity, cytotoxic, and genotoxic indicators.

RESULTS

A dose-dependent leukopenia, eosinophilia, neutrophilia, and thrombocytopenia were noted. Also, the immunoglobins G (IgG) and IgM were significantly elevated in TiO₂ treated rats. The phagocytic activities, lysozyme, nitric oxide, and immunoglobulin levels were significantly depleted following TiO₂ exposure. A significantly reduced lymphocyte proliferation but elevated LDH activity was prominent in TiO₂ treated rats. Different pathological perturbations were observed in both splenic tissue and bone marrow. A marked increase in CD4⁺ and CD8⁺ immunolabeling was evident. A significant increase in the comet variables was recorded in response to the exposure of rats to the increasing level of TiO₂ at both levels.

CONCLUSION

Overall, these results indicated that TiO₂ could induce hematotoxicity, genotoxic, and immunotoxic alterations with exposure for long durations.

[Preclinical tests of additive materials for personified endoprostheses of hand joints]

AIM

To evaluate the biocompatibility of additive materials for personified endoprostheses of hand joints in vivo.

MATERIAL AND METHODS

We tested a material based on titanium that was implanted into muscles and bone tissue in experiment on rabbits. Follow-up was 30 and 90 days.

RESULTS

Implantation into muscle tissue is accompanied by reaction against foreign body followed by fibrosis without concomitant inflammation. Induction of osteogenesis and trabecular structures remodeling were detected after implantation into bone tissue.

CONCLUSION

Biocompatibility of tested titanium-based material was confirmed.