This study examined the effects of cerium oxide nanoparticles (CeO2 NPs) on disease progression in a transgenic mouse model of amyotrophic lateral sclerosis (ALS). The mice expressed a mutation in the SOD1 gene associated with familial ALS. Following disease onset, mice were given injections of either saline (control) or CeO2 NPs. Mice treated with CeO2 NPs showed improved motor performance and increased survival time, particularly female mice. The results suggest CeO2 NPs may be a potential treatment for slowing progression of ALS and other neurodegenerative diseases associated with oxidative stress.

1. Effects of Cerium Oxide Nanoparticles on Disease Progression in a Transgenic
Mouse Model of Amyotrophic Lateral Sclerosis
A. S. Gardner1, J. D. Pusey1, M. K. Hamel3, J. A. Foster-Moore1, M. U. Prajapati1, K. Heckman2, W.E. DeCoteau1,3 and J.S Erlichman1,2
Program in Neuroscience1 and Departments of Biology2 and Psychology3, St. Lawrence University, Canton NY
Introduction
Oxidative stress is a factor in the onset and progression of many
neurodegenerative diseases. Oxidative stress occurs when reactive
oxygen species (ROS) accumulate and damage cellular structures.
Antioxidants can act therapeutically to reduce tissue death and increase
survival. In this study we examined the neuroprotective effects of ceria
nanoparticles on survival interval and motor decline in a transgenic murine
model of Amyotrophic Lateral Sclerosis (ALS).
A glycine to alanine substitution at position 93 of the SOD1 protein
(G93A ) reflects characteristics of familial ALS, and thus expression of
this SOD1 mutation has been implemented as a mouse model of ALS
through adopting a toxic gain of function. This gain of function induces
the upregulation of SOD1 which becomes toxic, increasing the
production of hydroxyl radicals from hydrogen peroxide precursors.
Disease onset is spontaneous and usually occurs around 100-120
days of age, life expectancy is normally two to four weeks beyond
onset of observable clinical symptoms.
G93A Model
Normal SOD activity
SOD ↑H2O2Superoxide anion Catalase
activity
↑H2O and O2
Behavioral Testing and Clinical Scores
Cerium Oxide Nanoparticles
Cerium oxide nanoparticles (2.5nm) are made up of 80 atoms in the
form of a lattice structure that have oxidation-reduction properties
believed to scavenge free radicals by trapping them in their oxygen
vacancies and shuffling them between the +3 and +4 states. Due to
their ability to scavenge free radicals, it is hypothesized that cerium
oxide could reduce motor degeneration and neuron loss resulting from
the production of free radicals.
Past Experimental Paradigm
Table 1. ALS clinical scale
Conclusion
The results of this study indicate CeO2 NP treatment :
• increased survival in the G93A mouse model of ALS. The effect was more
pronounced in female mice.
• improved “quality of life” in the G93A mouse model of ALS as measured by
body weight and grip strength changes following disease onset.
• shows promise as a treatment for familial ALS and other human disorders
related to oxidative stress.
CeO2 Nanoparticle Treatment
Following disease onset, all mice (23 males, 33 females) were given semi-weekly tail
injections of either saline or CeO2 NPs (20 mg/kg) mixed in saline. Drug treatment and daily
hanging wire testing, clinical scoring, and body weight measurements were carried out until
animals reached the disease endpoint defined as scoring <2.5 on the clinical score or losing
more than 20% drop of baseline body weight.
Acknowledgments
We would like to Liz McDougall, Abby Korn and Alyssa Couse for their help with animal care,
Bonnie Erlichman and Krista Bray, for injections; Mike Temkin, for genotyping and Cerion
Energy (Rochester, NY) for providing the nanoparticles.
ALS
ALS is a neurodegenerative disease characterized by muscular atrophy;
initially hindering limb movement and ability to swallow, progressing to full
body paralysis. Most familial cases of ALS are related to a mutation to the
superoxide dismutase 1 (SOD1) gene, a natural catalytic antioxidant,
which results in increased of free radicals, such as superoxide. Treatment
for ALS is currently aimed at slowing disease progression and targets
symptoms of the disease after onset.
Present Experimental Paradigm
Treatment Group
MeanLatencytoFall(s)
0
20
40
60
80 Control
Drug
P = 0.687
(Males)
(Females)
Treatment Group
MeanLatencytoFall(s)
0
10
20
30
40
50 Control
Drug
P = 0.238
Pre-Disease Hanging Wire Performance
Hanging Wire Performance (Males)
Days Following Disease Onset
0 5 10 15 20 25
MeanLatencyToFall(s)
0
20
40
60
80
100
Control
Drug
Hanging Wire Performance (Females)
Days Following Disease Onset
0 5 10 15 20 25
MeanLatencyToFall(s)
0
10
20
30
40
50
60
Control
Drug
* * * * ** ***** *
** **** * * * ** * *
n=23
n=33
Fig 3 (left). Female mean latency to fall as a function treatment group (control vs drug) and day following disease onset.
Fig 3 (right). Overall male mean latency to fall (s) as a function treatment group (control vs drug).
Hanging Wire Performance (Males)
Days Following Disease Onset
0 5 10 15 20 25
MeanLatencyToFall(s)
0
20
40
60
80
100
Control
Drug
Hanging Wire Performance (Females)
Days Following Disease Onset
0 5 10 15 20 25
MeanLatencyToFall(s)
0
10
20
30
40
50
60
Control
Drug
* * * * ** ***** *
** **** * * * ** * *
n=23
n=33
Fig 2 (left). Male mean latency to fall (s) as a function treatment group (control vs drug) and day following disease onset.
Fig 2 (right). Overall male mean latency to fall (s) as a function treatment group (control vs drug).
Fig 4. Percent survivors for males (left) and females (right) as a function of treatment (control vs drug) and days after
disease onset. Kaplan-Meyer regression analyses indicate a significant increase in survival trajectory for females but not males.
Fig 1. Mean male and female pre-disease onset hanging wire performance.
Results
Prior to disease onset all mice were trained (males at ~ age 85 days; females at ~ age 100
days) daily on the hanging wire task that measures grip strength. Latency to fall (180s max)
from an elevated and inverted wire floor was measured. Two consecutive decreases from
baseline performance was used to mark “disease onset.” Following disease onset animals
were assigned to treatment groups and were scored for clinical symptoms (table 1).
Score Symptoms
5.0 Normal movement; no paralysis
4.5 Clumsy gait
4.0
Limping or dragging of at least 1
hind limb
3.0
1 hind limb is extended (not
spontaneously flexed)
2.5 Both hind limbs extended
2.0
Bilateral hind limb failure and
paresis in 1 forelimb
1.0
Animal cannot right itself within
30 seconds