Acute and subacute toxicities of biogenic tellurium nanorods in mice

Abstract

The current study was performed to evaluate the acute and subacute toxicities of biogenic tellurium nanorods (Te NRs). The Te NRs were prepared using Pseudomonas pseudoalcaligenes strain Te in a culture medium containing K₂TeO₃ (1 mM) and their physiochemical properties were investigated using TEM, EDX and XRD. The median lethal dose (LD₅₀) of Te NRs and potassium tellurite (K₂TeO₃) were determined in mice and the subacute toxicity was also evaluated. The experimental design involved certain general toxicological, haematological, serum and histopathological investigations. The TEM and XRD analyses showed that the biogenic nanoparticles were rod-shaped and hexagonal. The toxicological evaluation showed that the LD₅₀ values of Te NRs and K₂TeO₃ were 60 and 12.5 mg/kg, respectively. Higher doses of Te NRs (6 mg/kg) and K₂TeO₃ (1.25 mg/kg) were accompanied by signs of toxicity, including lower body weight, elevation in MDA and depletion in GSH content, SOD and CAT activity, and changes in biochemistry parameters. No obvious histopathological changes were observed in the treatment with Te NRs. In conclusion, the biogenic Te NRs were less toxic as compared to K₂TeO₃, and the no-observed-adverse-effect level (NOAEL) dose of Te NRs in 14 days subacute toxicity study was lower than 1.2 mg/kg.

Keywords: Biogenic Te nanorods; Lethal dose; Nanotoxicity; Oxidative stress.