Cytotoxicity Testing Using Cell Lines

Commercially exploitable compounds are being produced using modern biotechnology for use as food additives, chemotherapeutic agents, and pesticides. Traditionally, animal testing has always played an important role in the safety evaluation of such agents. However, financial and ethical considerations, together with an increased awareness of the limitations of animal models in relation to human metabolism, now warrant the development of alternative testing methods. Therefore, it is fitting that the potential of biotechnology should provide mammalian cell systems for in vitro testing. The ultimate aim of in vitro toxicity testing is the replacement of animals in testing protocols, but in the short term, procedures are refined to reduce the numbers of animals required. This “three Rs” philosophy of reduction, refinement, and replacement was first proposed by Russell and Burch as early as 1959 (1 ), and is now recognized in the UK Animals in Scientific Procedures Act, 1986 and EC Directive 86/609/ECC (2 ).