2. Preclinical Studies
The number of animals used in preclinical studies is
continuously increasing. Each year millions of experimental
animals across the world are sacrificed in the name of scientific
research.
The pain, distress and death experienced by the animals
during scientific experiments have been an issue of debate since
long.
Besides the major concern of ethics, there are few more
disadvantages of using animals for scientific experiments, like
requirement of skilled manpower, time consuming protocols,
and high cost.
3. Considering these disadvantages, many alternatives
to animal testing have been proposed. Currently, a
strategy of 3Rs (reduction, refinement, and
placement) is being applied for using animals in
research labs.
4. Strategy of 3Rs
The strategy of 3Rs was first suggested by Russell and
Burch in 1959 to make animal experiments more human
and ethical.
Their approach motivates to use minimum number of
animals in an experiment, plan and refine experiments to
minimize pain and distress to the animals, and finally
replace higher animals with alternative methods and lower
organisms.
5. 1) Reduction
In vitro cell cultures have provided a safe alternative to
reduce the use of animals in lab testing. By using in vitro
cell cultures like human hepatocyte culture, embryonic
stem cell culture etc., you can easily get relevant
information about the metabolism and excretion of drugs
from the body.
Inclusion of these methods in study design and sharing of
the discovered data will eliminate unsuitable drug
compounds in preliminary stages and minimize the use of
animals in further research.
6. 2) Refinement
When the cage environment of the animals used in
experiments is not suitable, it adds to the stress on
animals. Their hormone levels fluctuate and the results are
not satisfactory. Thus, the experiments have to be repeated
causing an increase in the use of experimental animals.
The experiments can be refined by enriching the cage
environment of the experimental animals. This not only
reduces the pain and discomfort in animals, but will also
improve the quality of research.
7. 3) Replacement
Various alternatives like in vitro cell cultures,
computer models, and new imaging techniques are now
being used in place of experimental animals.
Besides reducing the use of animals, these alternative
methods are time-effective, cost-effective, and require
less manpower.
8. a) Cell and Tissue Cultures
Use of in vitro cell and tissue cultures involves the growth
of cells outside the body in a laboratory environment and
offer an important alternative for animal experiments.
The cells and tissues from the liver, kidney, brain, skin etc.
are removed from an animal and kept outside the body in a
suitable growth medium for few days to several months or
years.
Cell cultures are routinely used in preclinical studies to
know the toxicity and efficacy of potential drug molecules.
They are cost and time-effective and easy to follow.
9. b) Computer Models
Computers help us to understand the basic principles of
biology. Specialized computer models and software
programs have been designed to predict the various possible
biological and toxic effects of a chemical or potential drug
candidate without animal dissection.
This way unsuitable drug gets eliminated in primary
screening and only the most promising ones are used
for animal experimentation.
These software programs give speed and cost-effectiveness
to the preclinical studies.
10. c) Alternative Organisms
Owing to the ethical issues regarding the use of
experimental animals like pigs, rats, dogs, and monkeys, use
of alternative organisms has been proposed.
Different model organisms that can be used as alternatives
to animals include micro-organisms such as bacteria and
fungi, lower vertebrates like zebra fish, and invertebrates like
flies.
These alternative organisms reduce the required working
space, cost of laboratory solutions, test chemicals and the
manpower besides the use of experimental animals.
11. Thus, the issue of animal ethics can’t be
ignored and more efforts must be undertaken to
effectively implement the 3 Rs strategy during
laboratory use of animals.
For this, various computer models, in vitro cell
cultures, enzymatic screens, and alternative
model organisms must be integrated. The
integrated approach would result in minimum
involvement of animals in preclinical research.
