A comparative study of the toxicological aspects of vanadium pentoxide and vanadium oxide nanoparticles

Indiscriminate use of vanadium oxide nanoparticles (NPs) in steel industries and their release during combustion of fossil fuels makes it essential to study their toxic potential. Herein, we assessed the toxicological effects of two types of in-house synthesized vanadium oxide NPs in Wistar rats exposed to NPs through inhalation route. V₂O₅ and VO₂ NPs exhibited rod and spherical symmetry, respectively with a mean diameter of 50 ± 20 and 30 ± 10 nm. Assessment of bronchoalveolar lavage fluid parameters demonstrated that VO₂ NP-exposed animals had higher levels of lactate dehydrogenase, gamma-glutamyl transpeptidase and alkaline phosphatase as compared to V₂O₅ NP-exposed animals. The levels of oxidative stress markers malondialdehyde and reduced glutathione also indicated higher toxic potential of VO₂ NPs. Moreover, after 7-day recovery, the levels of the above parameters were closer to normal levels only in V₂O₅-exposed animals. Interestingly, histopathological and immune-histopathology analysis (TNF-α) of lung tissue showed higher damage and inflammatory response in VO₂ NP-exposed animals, which persisted even after 7 days of recovery period. Surprisingly, the carcinogenic potential of vanadium oxide NPs came into light which was indicated by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay as well as the decreased levels of p53 and Bax, in lung tissue of NP-exposed animals. Notably, the physiochemical characterization of NPs, especially the shape and the size, play a central role in shaping the toxicity of these NPs and thus should be extensively evaluated for outlining the regulatory guidelines.