RESUMO
Monocyte locomotion inhibitory factor (MLIF) is a pentapeptide produced by Entamoeba histolytica that has a potent anti-inflammatory effect. Either MLIF or phosphate buffered saline (PBS) was administered directly onto the spinal cord (SC) immediately after injury. Motor recovery was evaluated. We also analyzed neuroprotection by quantifying the number of surviving ventral horn motor neurons and the persistence of rubrospinal tract neurons. To evaluate the mechanism through which MLIF improved the outcome of SC injury, we quantified the expression of inducible nitric oxide synthase (iNOS), interleukin-10 (IL-10), and transforming growth factor- ß (TGF- ß ) genes at the site of injury. Finally, the levels of nitric oxide and of lipid peroxidation were also determined in peripheral blood. Results showed that MLIF improved the rate of motor recovery and this correlated with an increased survival of ventral horn and rubrospinal neurons. These beneficial effects were in turn associated with a reduction in iNOS gene products and a significant upregulation of IL-10 and TGF- ß expression. In the same way, MLIF reduced the concentration of nitric oxide and the levels of lipid peroxidation in systemic circulation. The present results demonstrate for the first time the neuroprotective effects endowed by MLIF after SC injury.
Assuntos
Entamoeba histolytica/química , Locomoção/efeitos dos fármacos , Oligopeptídeos/administração & dosagem , Traumatismos da Medula Espinal/tratamento farmacológico , Animais , Células do Corno Anterior/efeitos dos fármacos , Células do Corno Anterior/fisiopatologia , Humanos , Interleucina-10/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Fármacos Neuroprotetores/administração & dosagem , Óxido Nítrico Sintase Tipo II/metabolismo , Oligopeptídeos/química , Ratos , Medula Espinal/efeitos dos fármacos , Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/patologia , Fator de Crescimento Transformador beta/metabolismoRESUMO
In the Wobbler mouse, a mutation in the Vps54 gene is accompanied by motoneuron degeneration and astrogliosis in the cervical spinal cord. Previous work has shown that these abnormalities are greatly attenuated by progesterone treatment of clinically afflicted Wobblers. However, whether progesterone is effective at all disease stages has not yet been tested. The present work used genotyped (wr/wr) Wobbler mice at three periods of the disease: early progressive (1-2 months), established (5-8 months) or late stages (12 months) and age-matched wildtype controls (NFR/NFR), half of which were implanted with a progesterone pellet (20 mg) for 18 days. In untreated Wobblers, degenerating vacuolated motoneurons were initially abundant, experienced a slight reduction at the established stage and dramatically diminished during the late period. In motoneurons, the cholinergic marker choline acetyltransferase (ChAT) was reduced at all stages of the Wobbler disease, whereas hyperexpression of the growth-associated protein (GAP43) mRNA preferentially occurred at the early progressive and established stages. Progesterone therapy significantly reduced motoneuron vacuolation, enhanced ChAT immunoreactive perikarya and reduced the hyperexpression of GAP43 during the early progressive and established stages. At all stage periods, untreated Wobblers showed high density of glial fibrillary acidic protein (GFAP)+ astrocytes and decreased number of glutamine synthase (GS) immunostained cells. Progesterone treatment down-regulated GFAP+ astrocytes and up-regulated GS+ cell number. These data reinforced the usefulness of progesterone to improve motoneuron and glial cell abnormalities of Wobbler mice and further showed that therapeutic benefit seems more effective at the early progressive and established periods, rather than on advance stages of spinal cord neurodegeneration.
Assuntos
Neurônios Motores/efeitos dos fármacos , Neurônios Motores/patologia , Neuroglia/efeitos dos fármacos , Neuroglia/patologia , Progesterona/farmacologia , Doenças da Medula Espinal/patologia , Medula Espinal/patologia , Animais , Células do Corno Anterior/efeitos dos fármacos , Células do Corno Anterior/enzimologia , Células do Corno Anterior/patologia , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Astrócitos/patologia , Contagem de Células , Colina O-Acetiltransferase/metabolismo , Modelos Animais de Doenças , Feminino , Proteína GAP-43/genética , Proteína GAP-43/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Genótipo , Proteína Glial Fibrilar Ácida/metabolismo , Glutamato-Amônia Ligase/metabolismo , Processamento de Imagem Assistida por Computador , Masculino , Camundongos , Camundongos Mutantes Neurológicos , Neurônios Motores/enzimologia , Neuroglia/enzimologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismo , Doenças da Medula Espinal/enzimologiaRESUMO
To study the mechanisms by which glutamate-elicited acetylcholinesterase release (GEAR) might play a part in the pathogenesis of excitotoxically triggered motor neurone disease, and to investigate the interaction of GEAR with spinal glycinergic mechanisms, we measured acetylcholinesterase (AChE) and cholinergic markers, after stimulating ventral horn slices and synaptosomes from the mouse spinal cord, with both glutamate- and glycine-receptor agonists. Glutamate (GLU), kainate and AMPA, as well as glycine (GLY) evoked dose-related, calcium-dependent liberation of soluble forms of AChE from both slices and synaptosomes. GLY-evoked AChE release showed remarkable age-related postnatal changes. In the immature slice of the ventral horn. GLY potentiated the GEAR response in the presence of strychnine, suggesting N-methyl-D-aspartate (NMDA) receptor involvement, and was also able to evoke a strychnine-sensitive AChE release in the absence of exogenous GLU. After the 28th postnatal day, nearly all the AChE secreted was released either after the activation of non-NMDA glutamate receptors or by strychnine-sensitive GLY-evoked AChE release mechanisms. Both GEAR and GLY-evoked AChE release might impair the negative feedback loop which modulates the overactivation of motor neurones, and cause prolonged extracellular rises of soluble AChE. These effects might augment the vulnerability of motor neurones to excitotoxic stress, promote fiber outgrowth, and eventually accelerate the metabolic exhaustion of lower motor neurones. It is possible that the mechanisms described are operative at the spinal cord of ALS/MND patients.