Tissue engineering, defined as using a combination of cultured cells and biodegradable scaffolds to repair tissue damaged by injury or disease, represents a booming sector of biomedical research. Animal experimentation is routinely performed prior to clinical trials. The presented study tries to translate the aspect of the 3Rs to tissue engineering research: Cell culture protocols were adapted to antibiotic free and serum free conditions. Biomaterials (Bio-Gide and a collagen sponge prototype) were pre-tested using the HET-CAM assay. CAM-testing suggested a protocol change for application of the Bio-Gide scaffold and demonstrated unsuitable material properties of the collagen sponge. Application of 3R compliant protocols for tissue engineering research led to increased cell proliferation, higher synthesis of extracellular matrix molecules, reduced dedifferentiation and more information about the biomaterials at an early experimental stage. Tissue engineering research can therefore profit from the increased efforts to validate in vitro alternatives and supplements to animal testing.

The implantation of new biomedical devices into living animals without any previous toxicity or biocompatibility evaluation is possible under current legislation. The HET–CAM (Hen Egg Test–Chorionallantoic Membrane) test offers a partially immunodeficient, borderline in vitro/in vivo test system that allows the simulation of transplantation experiments to obtain biocompatibility data prior to animal testing. A collagen type I/III scaffold, designed for tissue regeneration, was tested for angiogenetic properties and biocompatibility patterns. A significant angiogenetic stimulus caused by the collagen scaffold material was observed. Altering biocompatibility patterns by incubation with the potentially hazardous chemicals acridine orange and ethidium bromide led to severe vessel thrombosis and a foreign body tissue response. CAM testing of biomaterials and tissue engineered products allows selection of the most suitable biomaterial and the elimination of unsuitable materials from animal experiments, leading to a refinement of testing procedures and a reduction in the number of animals required for biocompatibility testing.