Oxidative Stress in Long-Term Exposure to Multi-Walled Carbon Nanotubes in Male Rats

Abstract

Multi-walled carbon nanotubes (MWCNTs) serve as nanoparticles due to their size, and for that reason, when in contact with the biological system, they can have toxic effects. One of the main mechanisms responsible for nanotoxicity is oxidative stress resulting from the production of intracellular reactive oxygen species (ROS). Therefore, oxidative stress biomarkers are important tools for assessing MWCNTs toxicity. The aim of this study was to evaluate the oxidative stress of multi-walled carbon nanotubes in male rats. Our animal model studies of MWCNTs (diameter ~15–30 nm, length ~15–20 μm) include measurement of oxidative stress parameters in the body fluid and tissues of animals after long-term exposure. Rattus Norvegicus/Wistar male rats were administrated a single injection to the knee joint at three concentrations: 0.03 mg/mL, 0.25 mg/mL, and 0.5 mg/mL. The rats were euthanized 12 and 18 months post-exposure by drawing blood from the heart, and their liver and kidney tissues were removed. To evaluate toxicity, the enzymatic activity of total protein (TP), reduced glutathione (GSH), glutathione S–transferase (GST), thiobarbituric acid reactive substances (TBARS), Trolox equivalent antioxidant capacity (TEAC), nitric oxide (NO), and catalase (CAT) was measured and histopathological examination was conducted. Results in rat livers showed that TEAC level was decreased in rats receiving nanotubes at higher concentrations. Results in kidneys report that the level of NO showed higher concentration after long exposure, and results in animal serums showed lower levels of GSH in rats exposed to nanotubes at higher concentrations. The 18-month exposure also resulted in a statistically significant increase in GST activity in the group of rats exposed to nanotubes at higher concentrations compared to animals receiving MWCNTs at lower concentrations and compared to the control group. Therefore, an analysis of oxidative stress parameters can be a key indicator of the toxic potential of multi-walled carbon nanotubes.

Investigating the Impact of Carbon Nanotube Nanoparticle Exposure on Testicular Oxidative Stress and Histopathological Changes in Swiss albino Mice

“…This is particularly crucial, as the excessive production of ROS can actively deplete the GSH reservoir while it acts to neutralize these highly reactive species. Importantly, this phenomenon has garnered supporting evidence from previous research, with the study by ref yielding consistent findings. This collective body of evidence underscores the robustness and relevance of understanding the interplay between MWCNT-NP-induced ROS and GSH depletion, contributing to a deeper comprehension of the oxidative stress mechanisms induced by nanomaterial exposure.…”

“…When MWCNT-NP come into contact with biological systems, they initiate ROS production, including superoxide radicals (O 2 •– ) and hydrogen peroxide (H 2 O 2 ), which are known to induce oxidative stress within cells. This oxidative stress disrupts the delicate balance between ROS generation and the body’s antioxidant defenses . Consequently, the primary antioxidant, reduced GSH, is called upon to counteract ROS, leading to its depletion as it reacts with these highly reactive molecules.…”

“…This oxidative stress disrupts the delicate balance between ROS generation and the body's antioxidant defenses. 10 Consequently, the primary antioxidant, reduced GSH, is called upon to counteract ROS, leading to its depletion as it reacts with these highly reactive molecules. This depletion drives a shift in 7 and 14 days resulted in notable decreases of 33 and 62% in the GSH/GSSG ratio compared to the healthy control group, as shown in Figure 6 and Table 1.…”

“…Some studies suggest that organs such as the spleen, kidneys, testes, and lungs are particularly vulnerable to oxidative stress induced by free radicals. 10 The research objectives of this study aim to investigate the intricate dose-time relationship between exposure to MWCNT-NPs and its consequential effects on oxidative stress levels within the testes of Swiss albino mice. This research seeks to systematically uncover how varying doses and durations of MWCNT-NP exposure influence the extent of oxidative stress in this pivotal reproductive organ.…”

“…CNTs pose particular challenges when it comes to their elimination from the body, increasing the risk of their accumulation in various organs. Some studies suggest that organs such as the spleen, kidneys, testes, and lungs are particularly vulnerable to oxidative stress induced by free radicals …”