Effect of Nano-sized Carbon Black Particles on Lung and Circulatory System by Inhalation Exposure in Rats

Abstract

ObjectivesWe sought to establish a novel method to generate nano-sized carbon black particles (nano-CBPs) with an average size smaller than 100 nm for examining the inhalation exposure risks of experimental rats. We also tested the effect of nano-CBPs on the pulmonary and circulatory systems.MethodsWe used chemical vapor deposition (CVD) without the addition of any additives to generate nano-CBPs with a particle size (electrical mobility diameter) of less than 100nm to examine the effects of inhalation exposure. Nano-CBPs were applied to a nose-only inhalation chamber system for studying the inhalation toxicity in rats. The effect on the lungs and circulatory system was determined according to the degree of inflammation as quantified by bronchoalveolar lavage fluid (BALF). The functional alteration of the hemostatic and vasomotor activities was measured by plasma coagulation, platelet activity, contraction and relaxation of blood vessels.ResultsNano-CBPs were generated in the range of 83.3-87.9 nm. Rats were exposed for 4 hour/day, 5 days/week for 4 weeks to 4.2 × 106, 6.2 × 105, and 1.3 × 105 particles/cm3. Exposure of nano-CBPs by inhalation resulted in minimal pulmonary inflammation and did not appear to damage the lung tissue. In addition, there was no significant effect on blood functions, such as plasma coagulation and platelet aggregation, or on vasomotor function.ConclusionWe successfully generated nano-CBPs in the range of 83.3-87.9 nm at a maximum concentration of 4.2 × 106 particles/cm3 in a nose-only inhalation chamber system. This reliable method can be useful to investigate the biological and toxicological effects of inhalation exposure to nano-CBPs on experimental rats.

Evaluating Adverse Effects of Inhaled Nanoparticles by Realistic In Vitro Technology

“…Overall, we found a single exposure to relevant doses of spark-generated AgNP and CNP to have low toxic effects on human bronchial epithelia. These findings are coherent with data from many rodent inhalation studies and a few studies in vitro showing no statistically significant cellular response after application of realistic NP doses [ 52 , 53 , 54 , 55 , 56 , 57 ]. Many other published in vitro studies, however, administered unrealistically high AgNP and CNP doses to achieve significant acute toxicity [ 58 , 59 , 60 , 61 , 62 ].…”

Acute toxicity of silver and carbon nanoaerosols to normal and cystic fibrosis human bronchial epithelial cells

“…In contrast, there was no evidence for toxic changes after 28 and 90 days of AgNP inhalation in rats (Hyun et al, 2008;Ji et al, 2007;Kim et al, 2011b). Similarly, inhalation studies with CNP in rats revealed only mild inflammatory and oxidative stress responses (Kim et al, 2011a;Li et al, 1999). The substantially higher toxicity of AgNP and CNP found by in vitro studies is likely due to extreme and unrealistically high concentrations of suspended NP (450 mg/mL) applied to submerged cells, and exposing the cells to all particles at once.…”

Reduced pulmonary function and increased pro-inflammatory cytokines in nanoscale carbon black-exposed workers

“…For example, inhalation of CB particles with a diameter of 83.3-87.9 nm for 4 weeks neither induced toxicity of the rat’s lungs nor elicited most of pulmonary pro-inflammatory cytokines. The histological analysis further revealed that nanoscale CB particles did not induce inflammatory responses in the respiratory system [ 42 ]. Another study indicated that a short-time inhalation of nanoscale CB particles at 10 mg/m 3 could not induce changes of IL-6, IL-8, and TNF-α in rat [ 43 ].…”