Acute and subacute toxicities of biogenic tellurium nanorods in mice

•Pseudomonas pseudoalcaligenes strain Te used to prepare Te NRs.•The median lethal dose (LD50) value for biogenic Te NRs was determined as greeter than potassium tellurite (K2TeO3) in mice.•Multi organs damage caused by biogenic Te NRs has been evaluated in subacute toxicity in mice.•Testis and kidney most sensitive to biogenic Te NPs and Te toxicity is to be defined.•Oxidative stress mechanism is responsible for biogenic Te NPs and Te-induced toxicity.

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.

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