ance regardless of the medications
given. This work caught the field by
surprise and brought a long-held be-
lief into question, namely whether one
type of mouse is representative of all
the others (Fig. 4). Jeff Mogil’s com-
ment about his own study speaks
volumes, “Frankly, we just published a
paper that scared the hell out of me.” In
the field of pain research, researchers
need to be cautious when generaliz-
ing the results from one mouse strain
to another, let alone to humans. This
same group of researchers later dem-
onstrated that when male scientists
worked with mice or rats a reduced
pain response was observed. Howev-
er, this effect was not observed when
females handled the rodents. Most in-
terestingly, the reduced pain response
occurred again when females wore
male T-shirts revealing that the sex
of an experimenter can influence pain
responses in rodents [5]. It appears
scientific truth is not only obscured by
different types of mice, but also by the
scientists who interact with them.
Figure 5. Four laboratory mouse strains
Source: Stanton Short / Jennifer L. Torrance Jax.
org
The days of debating nature versus
nurture are behind us. It is both the
interaction of genes and the external
environment that produce a given out-
come. But what about our internal en-
vironment? A recent paper highlighted
another aspect of animal research,
namely the sterility of it all. Laboratory
mice are housed in pristinely clean
environments, especially when com-
pared to their wild counterparts. Re-
cently, there has been growing inter-
est in the microbiome and the role that
gut bacteria play in health and disease.
In a study investigating exactly this,
researchers colonized laboratory mice
with gut bacteria from that of wild
mice and subsequently demonstrated
that laboratory mice harboring the
‘wild bacteria’ were more resistant to
viral infection and tumorigenesis mod-
els [6]. To demonstrate the impact of
Figure 6. Amyloid plaques are commonly found in Alzheimer’s patient neural tissue.
Source; BrightFocus Foundation
this experiment, let’s talk numbers. Of
the normal laboratory mice, 17% were
alive 18 days after intranasal infection
with the influenza virus, while 92% of
the bacterial carrying lab mice were
still squeaking around! Clearly, our
animal models are kept under artifi-
cial conditions that appear to have a
strong influence on disease suscepti-
bility, at least in our rodent friends.
Neurology is another field where
treatments have not much improved
despite the multimillions of dollars,
euros, pounds, and other currencies
invested in this research area. Alzhei-
mer’s disease has frustrated many re-
searchers as it still lacks any treatment
despite many transgenic mouse mod-
els developed to study this disease
(although one could argue that a true
mouse model of Alzheimer’s does not
exist). The most accepted explanation
of Alzheimer’s disease is the buildup
of a protein in brain cells known as
amyloid beta (Fig. 6). Unfortunately,
the majority of attempted Alzheimer’s
treatments have failed and none have
made it to market. Currently, there is
not an approved treatment that works
on amyloid beta, but there are Phase
III clinical trials (the final phase) in pro-
cess to test an antibody treatment
that reduces the amount of amyloid
beta. This study should be completed
by 2022.
Mice do allow for better science and
have helped advance our knowledge
of biological processes. In the end
though, mice are not humans and
their utility as guideposts along the
road to developing new medications
for humans can be misleading. Our
Figure 7. Scientists need to scrutinize all of their tools to conduct the best science possible.
Source: labdepotinc.com; shutterstock.com; Jax.org
26 | NEUROMAG | November 2017