Biomedical Engineering Reference
In-Depth Information
is conceivable that particles of an appropriate size could easily block the renal fenestrae leading to
rapid kidney failure and death.
14.3.4.1 Toxicity of Metals and Heavy Metals
The safety of metals and their
in vivo
use is an ongoing issue of contest. Divalent cations are recog-
nized to be toxic even at low concentrations in the body. Because of the possible reabsorption and
accumulation in the kidneys, the main problem with heavy metals is nephrotoxicity (Babier et al.
2005). For example, gadolinium-based contrast agents for clinical MRI analysis have been reported
to be associated with acute renal failure (Akgun et al. 2006).
Wang et al. studied acute toxicity of nano- and micro-scale zinc powder in healthy adult mice.
Renal histopathological examinations revealed that there were alterations of proteinaceous casts
in the tubules as well as renal tubular dilatations in nano-scale zinc powder-treated mice. The his-
topathological finding demonstrated that the oral exposure of nano-scale zinc powder could cause
more severe renal damage than micro-scale zinc powder, though the serum indicators did not show
obvious changes (Figure 14.3). It was concluded that the oral exposure of high-dose nano-scale zinc
powder could induce heavier renal damage and anemia in mice (Wang et al. 2006).
Free cadmium is accumulated in the kidneys of Sprague-Dawley rats after intraperitoneal injec-
tions, but intact nanoparticles were also detected, organular levels of which increased with the dose
(Arslan et al. 2011).
14.3.4.2 Toxicity of Copper Nanoparticles
Sil et al. (2011) performed a dose-dependent study by estimating blood urea nitrogen (BUN) and
creatinine levels; the different doses taken for this study were well correlated with the doses taken
by Chen et al. (2006). After the dose-dependent study, 200, 413, and 600 mg/kg body weight copper
nanoparticles were chosen for further studies. Serum BUN and creatinine levels were significantly
increased in the group exposed to copper nanoparticles in comparison to the control group, sug-
gesting renal dysfunction. Nanocopper exposure increased the production of ROS, reactive nitrogen
species (RNS), and altered the levels of oxidative stress-related biomarkers in kidney tissue.
Exposure to nano-sized copper particles caused alterations in the levels of intracellular ROS
as well as the production of NO (measured by nitrite level). It was also clear from this study that
(a)
(b)
GM
GM
RT
(c)
RT
GM
FIGURE 14.3
Kidney tissue from mice exposed to zinc powder at an acute toxic dose of 5 g/kg body weight
on 14 days post-oral administration (magnification = 200). (a) Control group (instilled 1% sodium carboxy
methyl cellulose). GM: glomerulus; RT: renal tubular. (b) Microscale group. Arrows show the glomerulus
swelling. (c) Nanoscale group. Arrows show the glomerulus swelling. Circle area shows the proteinaceous
casts in renal tubular. (Reprinted from Wang, B. et al. 2006.
Toxicol L ett
161:115-123. With permission.)
