Collagen-affecting drugs impair regeneration of teleost tail fins.

Regenerating tail fins were studied in two species of teleosts, Tilapia rendalli and Cyprinus carpio, treated with indomethacin, aspirin, dexamethasone, penicillamine, and beta-aminoproprionitrile, drugs known to disrupt collagen metabolism in mammals. Collagen was studied under the light microscope by the Picrosirius-polarization method and also under the electron microscope. In general, these drugs disturbed the deposition and organization of collagen fibrils leading to abnormally thin or practically absent lepidotrichia and actinotrichia, and also to disorganized fibrous connective tissue. The resulting disorganization of the collagenous scaffolding of the regenerating dermoskeleton was probably responsible for a secondary effect on blastema distalization and on the general fin ray patterning that were also observed. The foregoing observations suggest that the stromal histoarchitecture of the regenerate plays a vital role in fin regeneration and indicate that these drugs may be useful in studying the extracellular matrix-cell interactions at the cellular and molecular level. In addition, the present findings provide a basis for developing different biological models by using teleost fin regeneration.