RESUMO
A rat model of complete sciatic nerve transection was used to evaluate the effect of bone marrow mononuclear cells (BMMC) transplanted to the injury site immediately after lesion. Rats treated with BMMC had both sensory and motor axons reaching the distal stump earlier compared to untreated animals. In addition, BMMC transplantation reduced cell death in dorsal root ganglia (DRG) compared to control animals. Transplanted BMMC remained in the lesion site for several days but there is no evidence of BMMC differentiation into Schwann cells. However, an increase in the number of Schwann cells, satellite cells and astrocytes was observed in the treated group. Moreover, neutralizing antibodies for nerve growth factor (NGF) (but not for brain-derived neurotrophic factor and ciliary-derived neurotrophic factor) added to the BMMC-conditioned medium reduced neurite growth of sensory and sympathetic neurons in vitro, suggesting that BMMC release NGF, improve regeneration of the sciatic nerve in the adult rat and stimulate Schwann and satellite cell proliferation or a combination of both.
Assuntos
Transplante de Medula Óssea/métodos , Regeneração Nervosa/fisiologia , Neuroglia/fisiologia , Neurônios/fisiologia , Neuropatia Ciática/patologia , Neuropatia Ciática/cirurgia , Animais , Células da Medula Óssea/fisiologia , Bromodesoxiuridina/metabolismo , Morte Celular , Proliferação de Células , Células Cultivadas , Embrião de Galinha , Modelos Animais de Doenças , Gânglios Espinais/citologia , Masculino , Fator de Crescimento Neural/uso terapêutico , Regeneração Nervosa/efeitos dos fármacos , Proteínas do Tecido Nervoso/metabolismo , Neurônios/classificação , Neurônios/efeitos dos fármacos , Ratos , Neuropatia Ciática/tratamento farmacológico , Técnicas de Cultura de TecidosRESUMO
We have examined how herbimycin affects the survival and neuritogenesis of avian sympathetic neurons. Herbimycin promoted sympathetic neuron survival and neuritogenesis. At higher concentrations (> or = 100 ng/ml), herbimycin still enhanced neuron survival but blocked neuritogenesis. Addition of herbimycin (10-30 ng/ml) to neurons cultured in the presence of NGF or retinal conditioned medium altered neuronal morphology, with an increase in the number of neurites. Addition of NGF during hypoxia rescued 52% of the neurons compared to 14% survival in control conditions. Herbimycin alone rescued about 50% of the neurons. In the presence of NGF and 100 ng/ml herbimycin, 81% of the neurons survived hypoxia. Our results show that herbimycin promotes survival of chick sympathetic neurons and potentiates the effects of NGF.
