Abstract
Fibroblastg rowth factorsw ere found to act as a growth fa ctorsf or fibroblasts. L ittle attention has been paid, however, to the effect of the other growth factors such as the effect of neurotrophins on fibroblasts. The aim of this study was to evaluate effbcts of neurotrophins (nerve growth factor-β(NGF), the brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3)), and the insulin-like growth factor-1 (IGF-I) on the proliferation of fibroblasts. Furthermore, we evaluated the effects of these four growth factors on the buthionine sulfoximine (BSO)- and vincristine-induced apoptosis of fibroblasts. When cultured in a medium containing 10% FBS, NGF did not affect the survival of fibroblasts at concentrations of up to 30μM after 24-72 h incubation. Under the experimental conditions employed in serum free, NGF did not affect the survival of fibroblasts, irrespective of concentration and incubation time. Similarly, BDNF and NT-3 were not found to affect fibroblast survival despite the experimental conditions. In contrast, the addition of increasing concentrations of IGF-1 resulted in a concentration-dependent potentiation of fibroblast proliferation without 'serum after 48 h and 72 h incubation. In the presence of serum, IGF- I potentiated the proliferation of fibroblasts after 48 h incubation, but not after 72 h incubation. Glutathione-depleted fibroblast treated with BSO underwent cell death. In addition, the anti-cancer drug vincristine inhibited the survival of fibroblasts. IGF- I, but not the three neurotrophins which attenuated the cell death of fibroblasts with vincristine in the absence of serum. In the presence of serum, however, the four factors examined failed to alter the cell death of fibroblasts with vincristine or BSO. These results suggest that IGF-I, but not NGF, BDNF, NT-3 may potentiate fibroblast proliferation.
