Reptiles as Animal Models: Examples of their Utility in Genetics, Immunology and Toxicology (pp. 407-446)
Authors: (Gisela L. Poletta, Pablo A. Siroski, Patricia S. Amavet, Hugo H. Ortega and Marta D. Mudry, Universidad Nacional del Litoral, Argentina)
Abstract: Historically, animals used as experimental models have contributed to the knowledge of multiple aspects of organismsí biology and wildlife, providing valuable information about physiological processes, events, environmental situations, and even human interactions. Alternatives to animal testing are primarily based on biochemical assays or experiments with cells/organs cultures, typically far more sophisticated and specific than in vivo approaches. However, the whole organism allows for inferences about particular species and its situation in natural habitats. Sometimes, it is not possible to study directly the species of interest, making it necessary to identify the closest related species that can be used as a model organism. Reptiles may be good and interesting models as they respond both behaviorally and physiologically to environmental or experimental conditions. This chapter specifically describes the utility of crocodiles, lizards, and turtles as animal models in studies of genetics, immunology, and toxicology. The increased interest in reptile genomics is evident by newly sequenced genomes, by the establishment of significant genomic resources for some reptile groups, and by the awareness that genomic diversity in Reptiles is substantially greater than that of mammals. Reptiles also demonstrate immune components with an apparently higher activity than other vertebrates. Their ability to resist serious injuries makes them interesting models to elucidate mechanisms within the defense system. In the same way, interesting studies were performed to propose immune components to be used as indicators of toxics exposure. Environmental contaminants can significantly affect many reptiles. However, these species are often excluded from toxicology studies and ecological risk assessments, even though they are important elements of ecosystems and show similar sensitivity to that reported for birds and mammals. Genotoxicity, immunotoxicity and oxidative stress biomarkers provide promising alternatives for measuring the effects of different
compounds in reptile species, serving as early-warning signals of populations environmentally exposed.