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Some authors argue that animal experimentation, in
addition to being detrimental to maintaining life and
bodily integrity, avoiding pain and frustration, is also
non-consensual, given that it is conducted on living beings
that did not voluntarily agree to participate in the research.
Despite technological advances in alternative methods, it
is estimated that scientific research uses around 100 mil-
lion animals every year worldwide.
17-19
The use of animals in several studies remains unac-
ceptable to some people, even to some researchers, due to
their constant concern for animal welfare. However, some
important pieces of information are not always externalized,
such as animal care during the investigation and the role
of the veterinarian in this process, ensuring that it is pos-
sible to balance scientific goals and animal welfare.
20,21
Most scientists and some members of the general
public, nevertheless, agree that animal testing should be
allowed where there are no other viable alternatives and
provided that it is carried out under strict regulations.
They believe it is useful to investigate disease mechanisms,
validate new drugs, and to provide information on drug
toxicity and interactions.
7
The search for alternatives to animal experimentation,
including its educational aspect, is experiencing intense
evolution. These methods can be any given choice that
can replace, reduce or refine the use of animals in bio-
medical research, testing or teaching. In the latter, animal
experimentation can practically be replaced altogether
without major impairment to learning.
14,22
Some authors suggest the use of alternative techniques
to animal testing, since they consider it an immoral and
ineffective practice. These methods include in vitro tests
(tissues and cells); the use of vegetables; non-invasive
clinical studies in human volunteers; conducting studies
with corpses instead; the use of lower organisms that are
not classified as protected animals (shrimp and water flea
larvae); physicochemical techniques; computer simula-
tions; educational software; films; mathematical models;
nanotechnology; and test dummies.
22
Computer models run on specialized software and
lower organisms (Figure 3) are the alternatives of choice
for assessing the biological effectiveness of active drugs
and molecular/genetic studies,
23
respectively.
The use of porcine small intestine and pork belly skin
has proved useful in teaching suturing, grafting and surgical
knotting techniques. Still, the absence of bleeding restricts
the training for hemostasis, which is thus a limiting factor.
17-19
The embryo of zebra fish (Danio-rerio) is considered
a promising model for predicting toxicity in vertebrates,
including humans. Its rapid development and transpar-
ency facilitate the evaluation of phenotypic effects, mak-
ing it an effective model for the study of human diseases.
24
Still, these alternative methods are at different stages
of development and validation. This is a difficult and slow
process, since it entails collaborative studies, which are in
turn carried out in several places, and the analysis of inter-
and intra-laboratory variations.
22
They must undergo a
series of evaluations, such as effectiveness, safety, toxicity,
specificity, sensitivity and predictive value, before they can
eventually be validated as alternative methods.
8
Animal experimentation is still necessary for certain
teaching and research practices, since there is still no
sufficient technology to replace it altogether,
2
but there
has been a clear reduction in the number of studies in-
volving animals over the last decades.
25
It is undeniable that in vivo animal experimentation
has contributed to biological development and biomed-
ical research, yet it is also associated with high production
costs and strict ethical considerations. These limitations
led to the development of a cost-effective ex vivo model
that can effectively replace in vivo and in vitro models,
thus contributing to animal welfare.
26
Ex vivo models can be used to develop new therapies
in which the disease can be identified at an earlier stage
and treated with very advanced techniques. In dentistry,
with the development of an ex vivo culture model, the in-
vestigation of inflammatory cell behavior and metabolism
in different types of periodontal disease has become easy.
23,26
I
nvestigators
’
ethics
The behavior of investigators and professionals who use
animals in research has been changing based on the latest
FIGURE 3
Use of inferior organisms as an alternative method to
the use of vertebrate animals.