Comparative Studies of Orthovanadate Nanoparticles and Metformin on Life Quality and Survival of Senile Wistar Rats

Effect of prolong use of orthovanadate nanoparticles (GdVO₄/Eu³⁺ NPs (8 × 25 nm)) on life quality and survival of male Wistar rats on the late stage of ontogenesis (from 23 months to the end of life) has been investigated. Multi-parametric assessment of orthovanadate NPs influences against metformin (Met) which is a well-known calorie restriction mimetic (CR-mimetic) has been completed. The quality of life was assessed by taking into account age-related hallmarks-phenotype and some physiological parameters (condition of the coat, body weight, concentration of thyroxine, rectal temperature) as well as indicators of the pro-oxidant/antioxidant balance of blood and liver (the content of lipid hydroperoxides; aconitase, glutathione peroxidase, glutathione reductase, glutaredoxin activity, and activity of NADP⁺-dehydrogenases (DG) (glucose-6-phosphate DG, malate DG, and isocitrate DG)) in aging animals. Kaplan-Meier curve and Gehan tests with Yates' correction were performed for the survival analysis. It has been found that long-term use of GdVO₄/Eu³⁺ NPs (0.25-0.30 mg/kg/day), as well as Met (100-110 mg/kg/day) with drinking water led to reliable improvement of physiological parameters and normalization of the pro-oxidant/antioxidant balance in the liver and blood of experimental animals. A significant increase in the survival rate of aging rats was observed; the apparent median survival for control rats was 900 days, while for experimental rats, 1010 and 990 days for GdVO₄/Eu³⁺ NPs and Met, respectively. In general, the data obtained demonstrate the ability of GdVO₄/Eu³⁺ NPs and CR-mimetic-Met to improve the quality of life and increase the survival of an elderly organism.