Methods developed to replace animal use for scientific purposes often still make use of a variety of animal-derived materials whose production causes the animals pain and suffering. For example, fetal bovine/calf serum (FBS/FCS), which is used as a universal supplement in cell culture media, is derived from blood drawn from bovine fetuses discovered in pregnant cows during the slaughtering process. If this procedure is performed before the death of the fetus, it may cause the fetus pain and distress.

The journal ALTEX wishes to raise awareness of these issues and of the availability of alternative materials or production methods by recommending to authors to use or develop such approaches, which are also considered to offer better-defined and quality-controlled reagents than the animal-derived materials. While papers submitted for review will not be penalized for using such materials, authors will be asked to consider whether alternative materials might be tested for use in their system in future or would need to be developed from scratch. For example, the FCS-free database maintained by Utrecht University informs on alternative medium supplements to FBS/FCS. Reviewers of scientific papers in ALTEX already often suggest the replacement of FBS/FCS where applicable.

A further animal-derived material is Matrigel, commonly used as a cell scaffold for three-dimensional cell culture, which is produced from Engelbreth-Holm-Swarm (EHS) mouse sarcoma, a tumor grown and propagated in mice. Synthetic hydrogels have been developed as alternatives to Matrigel and some are commercially available.

Monoclonal antibodies, used to mark or bind molecules or to influence their activity, may still be purified from ascites fluid in mice in some countries. This involves inducing an inflammatory reaction in the peritoneal cavity of the mouse, injecting hybridoma (cancer) cells that produce the antibody into the peritoneum and later drawing out (tapping) the ascites fluid. Instead, antibodies can now be produced recombinantly and synthetic aptamers are also used as non-animal affinity reagents.

Obtaining primary animal cells from sentient animals will usually involve some level of pain for the donor animals and should be avoided where possible; models designed to reflect human physiological processes should preferably use human cell-based testing systems to avoid species-specific differences. Proteins and enzymes purified from animal tissue obtained by invasive sampling are often available in recombinant form, e.g. bovine serum albumin.

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