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.
Promising 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 sub-area.
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 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 resources:
EURL-ECVAM DataBase service on Alternative Methods to animal experimentation (DB-ALM)1:
DB-ALM 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:
The 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 (2019): EURL ECVAM dataset on alternative methods to animal experimentation (DB-ALM). European Commission, Joint Research Centre (JRC) [Dataset] PID: http://data.europa.eu/89h/b7597ada-148d-4560-9079-ab0a5539cad3