RESUMEN
Following an injury to their axons close to the cell body, adult motoneurons generally die. This type of injury, typically caused by avulsion of the spinal ventral root, initiates the activation of astrocytes and microglial cells and the extracellular space becomes loaded with excessive amounts of excitotoxic glutamate. We have provided evidence that, following ventral root avulsion and reimplantation, murine embryonic neuroectodermal stem cells (NE-GFP-4C) grafted into the rat spinal cord rescue the vast majority of the motoneurons that would otherwise die, and enable them to reinnervate peripheral targets. Stem cell grafts produced the modulatory cytokines IL-1-alpha, IL-6, IL-10, TNF-alpha and MIP-1-alpha, but not neurotrophic factors. The neurons and astrocytes in the ventral horn of grafted animals also produced IL-6 and MIP-1-alpha, indicating a strong interaction between the graft and the host tissue. The infusion of function-blocking antibodies against all cytokines into the grafted cords completely abolished their motoneuron-rescuing effect, while neutralization of only IL-10 suggested its strong effectivity as concerns motoneuron survival and a milder effect on reinnervation. It is suggested that, apart from the anti-inflammatory function of IL-10, the pro-inflammatory cytokines produced exert a strong modulatory function in the CNS, promoting the prevention of neuronal cell death.
Asunto(s)
Citocinas/metabolismo , Neuronas Motoras/fisiología , Placa Neural/trasplante , Radiculopatía/cirugía , Transducción de Señal/fisiología , Trasplante de Células Madre/métodos , Amidinas , Animales , Recuento de Células , Diferenciación Celular , Movimiento Celular , Supervivencia Celular/fisiología , Citocinas/genética , Modelos Animales de Enfermedad , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Captura por Microdisección con Láser , Ratones , Fuerza Muscular/fisiología , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
PURPOSE: Avulsion of one or more ventral roots from the spinal cord leads to the death of the majority of affected motoneurons. In this study we investigated whether immortalized clonal neuroectodermal stem cells applied to the injured cord in various ways impart neuroprotection on motoneurons otherwise destined to die. METHODS: The lumbar 4 (L4) ventral root of Sprague-Dawley rats was avulsed and reimplanted ventrolaterally into the injured cord. Clonal neuroectodermal murine stem cells (NE-GFP-4C) were placed in fibrin clot around the reimplanted root, were injected immediately following avulsion into the reimplanted ventral root or directly into the L4 segment. Three months after the primary surgery the L4 motoneuron pool was retrogradely labelled with Fast blue and the numbers of reinnervating motoneurons were determined. Functional recovery was tested biweekly through the use of the CatWalk automated gait analysis system. RESULTS: Transplantation of neuroectodermal stem cells into the reimplanted root or into the L4 spinal segment resulted in similarly extensive regeneration of the motoneurons (671 ± 26 and 711 ± 14 L4 motoneurons, respectively). In these groups significant functional recovery was achieved. The negative controls and animals with periradicular stem cell treatment showed poor motor recovery and reinnervation (42 ± 10 and 65 ± 2.5, respectively). CONCLUSION: This study provides evidence that neuroectodermal stem cell transplantation into the reimplanted ventral root induces as successful regeneration of injured motoneurons as stem cells grafted into the spinal cord.
Asunto(s)
Neuronas Motoras/fisiología , Regeneración Nerviosa/efectos de los fármacos , Placa Neural/trasplante , Células-Madre Neurales/fisiología , Traumatismos de la Médula Espinal/terapia , Animales , Supervivencia Celular/fisiología , Modelos Animales de Enfermedad , Femenino , Neuronas Motoras/citología , Neuronas Motoras/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Ratas , Ratas Sprague-Dawley , Recuperación de la Función/efectos de los fármacos , Traumatismos de la Médula Espinal/patología , Traumatismos de la Médula Espinal/fisiopatología , Raíces Nerviosas Espinales/fisiopatología , Raíces Nerviosas Espinales/cirugía , Trasplante de Células Madre/métodos , Trasplantes , Resultado del TratamientoAsunto(s)
Quimera/embriología , Codorniz/embriología , Trasplante Heterotópico/métodos , Animales , Trasplante de Tejido Encefálico/veterinaria , Embrión de Pollo , Modelos Biológicos , Placa Neural/embriología , Placa Neural/trasplante , Tubo Neural/embriología , Tubo Neural/trasplante , Trasplante Heterotópico/veterinariaRESUMEN
BACKGROUND: To circumvent ethical and legal complications associated with embryonic cell sources, investigators have proposed the use of nonneural donor sources for use in neural transplantation strategies. Leading candidate sources include autologous marrow stromal cells (MSCs) and fibroblasts, which are mesodermal derivatives. However, we recently reported that MSCs transplanted to the adult brain are rapidly rejected by an inflammatory response. Whether extrinsic variables or intrinsic mesenchymal traits stimulated inflammation and rejection is unknown. To determine the future utility of these cells in neural transplantation, we have now performed a systematic analysis of MSC transplantation to the brain. METHODS: To examine the effects of extrinsic variables on transplantation, green fluorescent protein (GFP)-expressing rat MSCs, cultured under distinct conditions, were transplanted stereotactically to the normal adult rat striatum, and donor survival and the host response was compared. To examine whether intrinsic donor traits promoted rejection, 50,000 GFP-expressing rat MSCs, fibroblasts, or astrocytes were transplanted stereotactically to the adult rat striatum and graft survival and the host response was compared. RESULTS: Irrespective of preoperative culture conditions, MSCs elicited an inflammatory response and were rejected by 14 days, indicating acute rejection was not mediated by culture conditions. Comparison of MSC, fibroblast, or astrocyte grafts revealed that mesenchymal derivatives, MSCs and fibroblasts, elicited an inflammatory response and were rapidly rejected, whereas neuroectodermal astrocytes demonstrated robust survival in the absence of inflammation. CONCLUSIONS: Our findings suggest that intrinsic characteristics of mesenchymal cells may stimulate host inflammation, and thus may not represent an ideal donor source for transplantation to the adult brain.