Regenerative abnormalities in hind limbs of bufo regularis induced by repeated amputations: I. Early larval stages

Abstract

The regenerative response of the hind limbs of early larval stages: 52, 53, 54 and 55 of Bufo regularis was studied following repeated amputations at the ankle level. The pattern of morphogenesis as well as skeletal configuration of the regenerates showed increasing degrees of abnormality, with a gradual reduction in the number of toes or phalanges, shortening of toes or complete cessation of regeneration, as the larvae grow older and the number of amputations increases. Reamputations at the same level resulted in structurally abnormal regenerates in 41-71% of the cases (at the different larval stages) following two amputations; and 78-96% of the cases following three amputations. The results suggested that the occurrence of abnormal regeneration was found to increase directly with the number of times the limb stumps were induced to initiate dedifferentiation and repair. The increase percentage of abnormal regenerates mostly established by stage 55, Series III, was the result of repeated amputation at the same level of the regenerating limb, combined with the greater differentiation of the limb tissues.