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

Geroprotective effects of GdVO4:Eu3 + nanoparticles, metformin and calorie restriction in male rats with accelerated aging induced by overnutrition in early postnatal ontogenesis

GdVO4:Eu3+ nanoparticles (OVNPs) have previously been shown to exhibit anti-aging effects in old rats.The accelerated aging model (overnutrition in early postnatal ontogenesis (POF)) was used to confirm the effect of OVNPs as a potential geroprotector. A comparative study of the effect of OVNPs, calorierestriction (CR) and CR-mimetic-metformin was carried out using a number of criteria: survival, prooxidant-antioxidant balance in the liver and blood, physiological parameters of male Wistar rats with accelerated aging. It was found that the survival of rats with POF was lower than that of control animals.It was found that the rate of superoxide radical formation and the content of lipid hydroperoxides in the mitochondria and microsomes of the liver and blood serum of rats with POF were higher, and the activities of glutathione peroxidases and the GSH content were significantly lower than in the control animals.It was also found that POF leads to perturbation of physiological parameters (body weight, liver weight, liver mass coefficient, body temperature and blood thyroxine concentration) characterizing the quality of life. Long-term use of OVNPs, CR or metformin in rats with accelerated aging normalized the imbalance of the prooxidant-antioxidant system, improved the physiological parameters, and increased the survival of these experimental animals. Moreover, the increase in survival was most pronounced with the use of CR and OVNPs. Considering our results andthe inadmissibility of long-term use of CR, it should be concluded that GdVO4:Eu3+ nanoparticles are promising for the development of agents that slow down the accelerated aging of an organism.

CeO2 nanoparticles improve prooxidant/antioxidant balance, life quality and survival of old male rats

Due to its unique redox chemistry, nanoceria is considered as potent free radical scavenger and antioxidant. However, their protective capacity in aging organisms remains controversial. To detect the anti-aging effects associated with the redox activity of 2 and 10 nm nano-CeO2, different test systems were used, including in vitro analysis, in situ assay of mitochondria function and in vivo studies of suitable nano-CeO₂ on aging of male Wistar rats from 22 months-old to the end of life. The 2 nm nanoparticles exhibited not only antioxidant (^·OH scavenging; chemiluminescence assay; decomposition of H₂O₂, phosphatidylcholine autooxidation) but also prooxidant properties (reduced glutathione and reduced nicotinamide adenine dinucleotide phosphate oxidation) as well as affected mitochondria whereas in most test systems 10 nm nano-CeO₂ showed less activity or was inert. Prolonged use of the more redox active 2 nm nano-CeO₂ (0.25-0.3 mg/kg/day) in vivo with drinking water resulted in improvement in physiological parameters and normalization of the prooxidant/antioxidant balance in liver and blood of aging animals. Survival analysis using Kaplan-Meier curve and Gehan tests with Yates' correction showed that by the time the prooxidant-antioxidant balance was assessed (32 months), survival rates exceeded the control values most considerably. The apparent median survival for the control rats was 900 days, and for the experimental rats-960 days. In general, the data obtained indicate the ability of extra-small 2 nm nano-CeO2 to improve quality of life and increase the survival rate of an aging organism.

UV Light-Activated GdYVO4:Eu3+ Nanoparticles Induce Reactive Oxygen Species Generation in Leukocytes Without Affecting Erythrocytes In Vitro

Nanoparticles (NPs) have been reported to be promising enhancement agents for radiation therapy. The aim of the study was to assess the cytotoxicity of UV non-treated and UV pretreated GdYVO₄:Eu³⁺ nanoparticles against erythrocytes and leukocytes by detecting eryptosis and reactive oxygen species (ROS) generation. Levels of intracellular ROS in erythrocytes and leukocytes using a ROS-sensitive dye 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA), as well as eryptosis rate utilizing annexin V staining, following direct exposure to UV-activated and nonactivated NPs were detected by flow cytometry. Blood cells were collected from 9 intact WAG rats. Neither the UV light-untreated GdYVO₄:Eu³⁺ NPs nor the treated ones promoted eryptosis and ROS generation in erythrocytes. Low concentrations of UV light-untreated NPs did not induce oxidative stress in leukocytes, evidenced by unaffected intracellular ROS levels. UV light treatment grants prooxidant properties to NPs, confirmed by NP-induced ROS overproduction in leukocytes. High concentrations of both UV light-treated and untreated NPs altered the redox state of leukocytes. UV light treatment imparts prooxidant properties to GdYVO₄:Eu³⁺ NPs, making them promising radiosensitizing agents in cancer radiation therapy.