Abstract

Since growth factors exert control over various cellular events during development and as information in this regard on regenerative growth are scant, the present study has evaluated the effect of exogenous in loco administration of EGF, TGF-β and NGF during the first few days post-autotomy on the course of tail regeneration in Hemidactylus flaviviridis. Further evaluated is the efficacy of NGF to rectify the retardatory influence of hypothyroidism on regeneration. This study reveals that, EGF and TGF-β inhibit tail regeneration while, NGF stimulates it. Histologically, the EGF treated lizards showed greater collagen formation and precocious epithelial and myogenic differentiation. TGF-β had inhibitory influence on dedifferentiation while favoring preponderant chondrogenic differentiation. Overall, the present study on the differential effects of growth factors on various aspects of cell proliferation and differentiation, suggest the need for various growth factors on a precisely synchronized temporal and spatial order for a normal regenerative growth.

Key words: Hemidactylus flaviviridis, regeneration, nerve growth factor, fibroblast growth factor, transforming growth factor-β.