The term Replacement refers to all methods which avoid or replace
animal use in preclinical research. Particularly in this principle of
the 3Rs, great progress has been made in recent years, sometimes
supported by other scientific developments such as CRISPR-Cas9,
Next-Generation-Sequencing and modern 3D-printing.
techniques such as organs-on-a-chip, in silico models, i.e. the
computer-aided modeling of biological processes, as well as 3D cell
cultures thus received not only scientific recognition but also broad
media interest. These methods are commonly displayed to represent the
majority of available replacement methods, although they represent only a
Replacement can be further divided into:
- Absolute Replacement:
Means that the use of animals is completely replaced by a substitute
method. Examples include in vitro methods such as animal-free cell
cultures, organoids and organs-on-a-chip, and in silico methods, for
example for the development of advanced pharmacological agents.
- Partial Replacement:
involves the use of invertebrates that, according to current scientific
knowledge, have no or only limited pain sensation, such as Drosophila
melanogaster - a fruit fly - , immature forms or early forms (e.g.
embryos of mammals, birds and reptiles) or bacteria.
- Relative Replacement: involves the use of animals solely to obtain cells, tissues or organs that are subsequently required for in vitro methods.
- due to the implementation of the 3Rs principle in the Austrian Animal
Experiments Act - the existence of replacement methods has to be
verified. If the specific question can be answered with these
alternative methods, they must also be used.
Ultimately, the complete replacement of animal experiments is the
highest goal of current research in the field of replacement methods.
this goal should be approached realistically, since especially for more
complex phenomena, for example neurodegenerative diseases such as
Alzheimer`s or Parkinson`s disease, animal experiments are currently
Future replacement methods for more complex disease models, which are
under development both internationally and nationally in institutions
such as the MUI animalFree Research Cluster and the biomedical research
centers in Graz and Vienna, could nevertheless bring this goal within
In areas where replacement methods are currently not an available
are two further approaches to optimize
to the ever-growing number of alternative methods, the search for
adequate and validated replacement methods can be very costly without
adequate resources. For this reason, several organizations have
specifically focused on the problem of searching and offer the following
EURL-ECVAM DataBase service on Alternative Methods to animal experimentation (DB-ALM)1:
represents a publicly available collection of alternative methods and
associated protocols that have been submitted to the Europan Centre for the Validation of Alternative Methods (ECVAM) for validation.
Link to the database: DB-ALM
ALTEX - Alternatives to Animal Experimentation:
open-access journal ALTEX is a peer-reviewed journal that has been in
existence since 1984 and is dedicated to publishing scientific articles
once a quarter on the topic of developing and promoting alternative
methods to animal experimentation. ALTEX is the official journal of the Center for Alternatives to Animal Testing (CAAT).
Link to the official page of the journal: ALTEX - Alternatives to Animal Experimentation
1 European Commission, Joint Research Centre
EURL ECVAM dataset on alternative methods to animal
experimentation (DB-ALM). European Commission, Joint Research Centre