Experimental Pathology

Part of current knowledge in human disease stems from exploring in vitro experiments and animal experimental disease. This pertains especially to diseases in which immune processes putatively constitute an early event, if not the primary one, in disease induction and maintenance. Good examples are systemic lupus erythematosus, rheumatoid arthritis and autoimmune thyroiditis. In most autoimmune diseases, an antigen, soluble and/or tissue bound, is recognized by its specific antibody and the ensuing immune-complex pesters the animal perpetually if not to death. The possibility to use knock-out animals lets us study the role of single components in the inflammatory process and direct therapeutic endeavor to those identified as crucial or at least founded upon conjecture and surmise if not on absolute proof. Among the experimental animals most often used we find rabbits, mice and guinea pigs. Worldwide it is estimated that the number of vertebrate animals—from zebrafish to non-human primates—ranges from the tens of millions to more than 100 million used annually. The Toll-like receptors were discovered on the fruit fly Drosophila. This now allows to a better understanding of kidney diseases and of Crohn's disease in humans. Animal experiments are closely related to developments in stem cell research which is why ethical committees with both human medical and veterinarian assignments are constantly updating our values and customs to be respected in the field. Animal experiments also lets us to develop more efficacious drugs, which may be curative if used during the acute phase but which have less a chance if used during the chronic phase of an immune complex disease.