Immunocytochemical studies of neurofilament antigens in the neurofibrillary pathology induced by aluminum

Intrathecal administration of aluminum salts induces accumulation of neurofilaments in axons and perikarya of motor neurons and is associated with impaired axonal transport of neurofilament proteins. Because phosphorylation of the 200-kilodalton (kd) neurofilament protein, thought to be a major component of the sidearms, seems to be important in interactions of neurofilaments with other cytoskeletal elements, we have postulated that aluminum may produce neurofibrillary pathology by altering patterns of neurofilament phosphorylation. To test this hypothesis, antibodies against phosphorylated and non-phosphorylated neurofilament epitopes were used for immunocytochemical analysis of spinal cord sections from aluminum-injected rabbits. In control animals, phosphorylated 200-kd neurofilament proteins were not demonstrable in perikarya of motor neurons. In experimental rabbits, perikarya and proximal axons of affected motor neurons showed striking accumulations of immunoreactivity of one phosphorylated epitope. The presence of phosphorylated 200-kd neurofilament proteins in these regions may have important consequences for the organization of the cytoskeleton and for the transport of neurofilaments. A similar, but not identical, pattern of accumulation of phosphorylated neurofilament immunoreactivity has recently been observed in neurofibrillary tangles in Alzheimer's disease.     

Immunocytochemical and ultrastructural evidence of dendritic degeneration in motor neurons of aluminum-intoxicated rabbits

Summary Using immunocytochemical and ultrastructural methods, we observed extensive and characteristic dendritic changes in motor neurons of rabbits inoculated intracisternally with aluminum phosphate. Anti-microtubule-associated protein 2 immunostaining revealed markedly reduced immunoreactivity in motor neuron dendrites and a reduced number of dendritic trees in aluminum phosphate-intoxicated rabbits. These dendritic changes were confirmed at the ultrastructural level; neurofilamentous accumulations, membranous inclusions and disrupted microtubules were common features of motor neuron dendrites, but less prominent in motor neuron axons. These observations suggest that dendrites are characteristically involved in aluminum intoxication in addition to the widely reported accumulation of phosphorylated neurofilament in perikarya and axons.     

Reversibility of neurofilamentous inclusion formation following repeated sublethal intracisternal inoculums of AlCl3 in New Zealand white rabbits

In this report, we describe the clinical, topographical and immunohistochemical characteristics of neurofilament (NF) inclusion formation induced by the intracisternal inoculation of young adult New Zealand white rabbits at 28-day intervals with 100 g AlCl₃ over the course of 267 days. The ability to recover following cessation of aluminum exposure has also been assessed. The extent of neurofilamentous inclusion formation was proportionate to the cumulative amount of AlCl₃ inoculated and initially consisted of fusiform axonal distention in the ventral spinal cord at day 51 following the initial inoculum. Spinal motor neuron perikaryal inclusions and discrete axonal spheroids were observed at day 107 and supraspinal neurofilamentous pathology by day 156. Perikaryal inclusions were immunoreactive to antibodies recognizing both poorly phosphorylated (SMI 32) and more highly phosphorylated high molecular weight NF (NFH). In contrast, axonal spheroids were intensely immunoreactive at all stages with antibodies recognizing highly phosphorylated NFH and an age-dependent NFH phosphorylation state (SMI 34) with only faint SMI 32 immunoreactivity. Immunoreactivity to an antibody recognizing ubiquitin-protein conjugates did not appear until day 156, whereas inclusions were not immunoreactive to antibodies recognizing either phosphatase-dependent or-independent microtubule-associated protein tau at any stage. Upon withdrawal from further AlCl₃ exposure after intervals of 51, 107 or 156 days following the initial inoculum, clinical recovery ensued in all rabbits. In all but the most severely affected rabbits, perikaryal neurofilamentous inclusions resolved. However, axonal spheroids continued to be prominent. However, axonal spheroids continued to be prominent. These studies demonstrate that the repetitive intracisternal inoculation of AlCl₃ in New Zealand white rabbits induces a reversible process of neurofilamentous inclusion formation that preferentially affects motor neurons, and in which recovery will occur in those inclusions containing an admixture of both poorly and highly phosphorylated NFH.     

Aluminum-induced chronic myelopathy in rabbits

Young adult New Zealand white rabbits, inoculated intracisternally once monthly with 100 micrograms AlCl3, developed progressive hyperreflexia, hypertonia, gait impairment, weight loss, muscle wasting and abnormal righting reflexes over the course of 8 months. No overt encephalopathic features were present. In spinal motor neuron perikarya, dendrites and axonal processes, argentophilic globular inclusions were extensive. Additionally, neurofibrillary tangle-like argentophilic inclusions were consistently present in the gigantocellularis, reticularis, raphe and trapezoid nuclei, but rarely present in the dorsal and ventral subiculum, parasubiculum and anterior thalamus, and never found in the cerebral cortex, substantia nigra, locus ceruleus, or cerebellum. All neuronal inclusions were immunoreactive with monoclonal antibodies recognizing phosphorylated and nonphosphorylated high and intermediate weight neurofilament proteins (SMI 31, SMI 32). Also, some spinal motor neuron inclusions were immunoreactive with a monoclonal antibody recognizing an 'age-related' phosphorylation state of neurofilament (SMI 34). Ultrastructurally, the inclusions consisted of straight or interwoven skeins of 10 nm filaments. This study demonstrates unique variability in the phosphorylation state of aluminum-induced neurofilamentous inclusions in a predominantly motor system degeneration induced by chronic low dose AlCl3.     

Accumulation of phosphorylated neurofilaments in anterior horn motoneurons of amyotrophic lateral sclerosis patients

Perikaryal collections of intermediate filaments have been described in the anterior horn motoneurons of patients with amyotrophic lateral sclerosis (ALS), but these inclusions have generally been considered rare and mainly associated with the familial form of ALS. Using the monoclonal antibody NF2F11, which recognizes phosphorylated neurofilament epitopes, we showed that focal collections of neurofilaments in anterior horn motoneurons were a characteristic finding in sporadic as well as in familial ALS; they were present in seven of nine ALS patients, but in none of nine control spinal cords. These neurofilamentous collections are not cross-reactive with antibodies directed against paired helical filaments and the microtubule associated protein tau. In addition, diffuse staining for phosphorylated neurofilament epitopes in chromatolytic anterior horn perikarya was significantly more frequent in ALS patients than in controls.     

Aluminum intoxication: a disorder of neurofilament transport in motor neurons

In the rabbit, intrathecal administration of aluminum salts (AlCl₃) induces accumulation of neurofilaments in nerve cells of the central nervous system. In motor neurons, the spatial pattern of neurofilamentous accumulation following aluminum intoxication suggests a defect in the axonal transport of neurofilament proteins. To test this hypothesis, we examined the distribution of radioactive cytoskeletal proteins in sciatic nerves of intoxicated and control animals. In the nerves of aluminum-injected animals, there was a 40% reduction in the relative amount of radioactive neurofilament proteins compared to tubulin. These results suggest that an abnormality in neurofilament transport may be important in the pathogenesis of the neurofibrillary pathology induced by aluminum intoxication.     

Long term proteasome inhibition does not preferentially afflict motor neurons in organotypical spinal cord cultures.

Ubiquitinated inclusions are a constant feature of amyotrophic lateral sclerosis (ALS). It has been hypothesised that these inclusions reflect overload or failure of the ubiquitin-proteasome system, and that this failure contributes to the degeneration of motor neurons. In the present study we have examined the effect of low concentrations of proteasome inhibitors on protein aggregation and viability of neurons in organotypical spinal cord cultures. We found a dose-dependent degeneration of neurons after a one-week exposure to the proteasome inhibitors lactacystin and epoxomicin. Neuronal degeneration was associated with an increase in poly-ubiquitination, consistent with failure of the ubiquitin-proteasome system. Proteasome inhibition caused degeneration of both motor neurons and interneurons, and no difference in survival between motor neurons and interneurons was observed. Since protein aggregation may particularly play a role in ALS patients with superoxide dismutase 1 (SOD1) mutations, we have compared the effect of proteasome inhibition between spinal cord cultures from non-transgenic and SOD1(G93A) transgenic mice. There was no difference between the viability of motor neurons from transgenic and non-transgenic mice.     

Potentiation in the neurotoxic induction of experimental chronic neurodegenerative disorders: N-butyl benzenesulfonamide and aluminum chloride.

Repeated monthly intracisternal inoculations of N-butyl benzenesulfonamide induced a chronic, slowly progressive myelopathy in young adult New Zealand white rabbits that was manifested by hyperreflexia, spasticity, hypertonia, gait impairment and altered tonic immobility responses. The neuropathological features consisted of scattered neuroaxonal spheroids, fusiform distention of the intramedullary portions of the spinal cord ventral roots and, as defined by microtubule-associated protein-2 (MAP 2) immunoreactivity, an initial distention and subsequent loss of dendritic processes in neurons of the nucleus motoris lateralis with the perikaryon of these cells remaining intact. A similar chronic progressive myelopathy was induced by repeated low dose intracisternal inoculations of aluminum chloride in New Zealand white rabbits. However, the neuropathological changes were more extensive and consisted of dendritic, axonal and perikaryal inclusions of phosphorylated and nonphosphorylated neurofilament localized to spinal motor neurons in the nucleus motoris medialis, substantia grisea intermedia and select brainstem nuclei with only minimal involvement of the nucleus motoris lateralis. The co-administration of these two neurotoxins over the course of 8 months induced striking behavioral changes as well as a fulminant myelopathy. This was accompanied by a loss of neuronal perikarya in the nucleus motoris accompanied by a loss of neuronal perikarya in the nucleus motoris lateralis and topographically extensive neocortical neurofilamentous degeneration. These features suggest that potentiation occurs when the two toxins are co-administered, a view supported by an estimation of the co-neurotoxicity coefficient (CNC greater than 1). Our results have implications for understanding human neurodegenerative disorders in which potentiation of insults may occur, producing a clinical and neuropathological disease state not expected from either agent alone.     

Heparan sulfate-like immunoreactivity in the spinal cord in motor neuron disease

Summary The spinal cords from eight autopsy cases of sporadic motor neuron disease (MND) and two control cases were immunohistochemically examined using anti-bodies directed to neurofilament proteins (anti-Nf) and to heparan sulfate (HepSS-1). Variable numbers of spheroids were observed in the anterior horns in the MND cases. In one case of MND, one third to half of the remaining anterior horn cells contained conglomerate inclusions in their perikarya. These pathological structures were not encountered in the control cases. The immunohistochemical study revealed that both anti-Nf and HepSS-1 intensely labelled all spheroids and conglomerate inclusions in the MND cases. The colocalization of heparan sulfate with neurofilamentous accumulation suggests that heparan sulfate is required for the aggregation of neurofilaments, resulting in the formation of spheroids and conglomerate inclusions in MND.Supported in part by the Amyotrophic Lateral Sclerosis Association (USA)     

Neurofilament reorganisation and neurofilament antigen redistribution in spinal motoneurones following retrograde axonal transport of diphtheria toxin

Single unilateral injections of diphtheria toxin (DTX) into the external anal sphincter muscle or internal intercostal nerve of cat induced characteristic ultrastructural lesions in corresponding ipsilateral spinal motoneurones 6–8 days later. The chief neuronal lesion was a progressive disruption of Nissl body composition and organisation, which between days 8–19 post injection was accompanied by a progressive accumulation of neurofilaments in motoneuronal perikarya and dendrites. Some axons in the ipsilateral ventral horn became hypertrophied due to neurofilamentous accumulation. Related immunocytochemical investigations 6–35 days after injection of DTX revealed abnormal immunoreactivity intoxicated motoneurones for 200-kDa and 160-kDa phosphorylated neurofilament proteins, but not in contralateral motoneurones. By day 35 abnormal neurofilament immunostaining also occurred in ipsilateral and some contralateral interneurones but not contralateral motoneurones. Abnormalities of Nissl body endoplasmic reticulum, neurofilament organisation, and neurofilament protein immunostaining were identical after either intraneural and intramuscular injections of DTX, indicating abnormalities were attributable to toxicity and not injection-related axonal damage. Since DTX acts specifically in the soma to inhibit protein synthesis, neurofilament abnormalities are secondary to cytotoxicity and probably result from deficits in transference of existing partially phosphorylated neurofilaments to the axonal transport system, or axonal transport per se.Supported by the Wellcome Trust and Motor Neurone Disease Association (UK)     

Neurofilament distribution is altered in the Mnd (motor neuron degeneration) mouse

Motor neuron degeneration (Mnd) is a genetic neurodegenerative disease of the mouse that is characterized by a progressive increase in motor dysfunction, moving from hind to fore limbs, leading to paralysis. An immunocytochemical analysis of the neurofilament distribution in spinal motor neurons in Mnd mice from all stages of the disease, including the presymptomatic, was performed using antibodies to different neurofilament subunits with different degrees of phosphorylation. Perikarya that stained with antibodies to phosphorylated neurofilaments were present in Mnd and control spinal cords, but the number of stained perikarya in Mnd was not significantly different from controls. There was a marked redistribution of neurofilaments within the cytoplasm of some motor neurons in Mnd cords. In Mnd but not controls, the immunoreaction product appeared marginated, leaving areas in the cytoplasm absent of immunostaining. These areas were observed in all stages of the disease, but less predictably in presymptomatics. Both the size of the areas and the number of motoneurons containing these areas appeared to increase with the severity of the disease. The number of anterior horn neurons in the hind limb region of lamina IX in spinal segment L4 of Mnd was lower than in controls, suggesting there is a loss of neurons in Mnd.     

Human midsized neurofilament subunit induces motor neuron disease in transgenic mice

Aberrant accumulation of neurofilaments is a feature of human motor neuron diseases. Experimentally motor neuron disease can be induced in transgenic mice by overexpressing the mouse neurofilament light subunit (NF-L), the human heavy subunit (NF-H), or mouse peripherin. Here we describe that mice harboring a bacterial artificial chromosome (BAC) transgene containing the human midsized neurofilament subunit (NF-M) gene develop a progressive hind limb paralysis associated with neurofilamentous accumulations in ventral horn motor neurons and axonal loss in ventral motor roots. Biochemical studies revealed that all three mouse neurofilament subunits along with the human NF-M contributed to filament formation, although filaments contained less peripherin. In addition the endogenous mouse NF-M became less phosphorylated in the presence of the human protein and accumulated in the cell bodies of affected neurons even though phosphorylated human NF-M did not. Remaining motor axons contained an increased density of neurofilaments and morphometric studies showed that principally small myelinated axons were lost in the transgenic animals. Removing half of the mouse NF-M by breeding the transgene onto the mouse NF-M heterozygous null background offered no protection against the development of disease, arguing that the effect is not simply due to elevation of total NF-M. Collectively these studies argue that the human and mouse NF-M proteins exhibit distinct biochemical properties and within mouse neurons are not interchangeable and that indeed the human protein may be toxic to some mouse neurons. These studies have implications for the use of human neurofilament transgenic mice as models of amyotrophic lateral sclerosis.     

Phosphorylated neurofilament antigens in neurofibrillary tangles in Alzheimer's disease

Neurofibrillary tangles (NFT) are a hallmark of Alzheimer's disease (AD), and their presence correlates with the presence of dementia. A major constituent of NFT is the insoluble paired helical filament which shares some antigenic relationships with normal cytoskeletal elements, particularly neurofilaments. If neurofilament proteins (200, 145-160, and 68 kilodaltons [kd]) participate in the formation of NFT, the distribution of these constituents might be expected to be abnormal. To examine this issue, we used immunocytochemical methods to localize phosphorylated and nonphosphorylated epitopes of neurofilament proteins in hippocampal neurons of controls and patients with AD. Normally, the 200-kd neurofilament protein is not phosphorylated in the perikarya of neurons. However, in AD, many pyramidal neurons contained immunoreactive phosphorylated neurofilaments. Patterns of immunoreactivity (linear, flame-shaped, or skein-like within perikarya) greatly resembled the appearance of silver-stained NFT. This pattern of immunoreactivity was not present in hippocampal pyramidal neurons in controls, except in one aged patient in whom adjacent silver-stained sections revealed a few NFT. Patterns of immunoreactivity with antibodies for nonphosphorylated neurofilament proteins were similar in control and AD neurons. Our results indicate that some NFT are associated with abnormal distributions of high molecular weight phosphorylated neurofilament proteins. One domain of the 200-kd protein is believed to be a component of the side arms which link neurofilaments and interact with microtubules. Abnormal interactions of perikaryal neurofilaments could play a role in the genesis of NFT, and this abnormality of the cytoskeleton could contribute to the dysfunction of neurons at risk in AD.     

Masses of phosphorylated neurofilaments are associated with abnormal Golgi apparatus of anterior horn neurons of β, β′‐iminodipropionitrile‐intoxicated rats

The Golgi apparatus (GA) of anterior horn neurons of rats chronically intoxicated with β,β′‐iminodipropionitrile (IDPN) in drinking water was examined with an organelle‐specific antibody. The neuropile of the anterior horns contained the typical axonal spheroids associated with IDPN toxicity while the perikarya of approximately one‐third of the neurons contained phosphorylated neurofilaments, which are not found in the perikarya of control rat neurons. By serial or double immunostaining with the SMI‐31 and anti‐MG 160 antibodies, there were no morphological changes of the GA in the majority of neurons including neurons with a mild to moderate degree of neurofilamentous accumulation. However, a few neurons with a massive accumulation of phosphorylated neurofilaments contained abnormal profiles of the GA which consisted of focal clustering, reduction in size and fragmentation. The results suggest that masses of phosphorylated neurofilaments are associated with struc‐tural abnormalities of the GA.     

Activated p38MAPK is a novel component of the intracellular inclusions found in human amyotrophic lateral sclerosis and mutant SOD1 transgenic mice

Cytoskeletal abnormalities with accumulation of ubiquilated inclusions in the anterior horn cells are a pathological hallmark of both familial and sporadic amyotrophic lateral sclerosis (ALS) and of mouse models for ALS. Phosphorylated neurofilaments besides ubiquitin and dorfin have been identified as one of the major components of the abnormal intracellular perikaryal aggregates. As we recently found that p38 mitogen-activated protein kinase (p38MAPK) colocalized with phosphorylated neurofilaments in spinal motor neurons of SOD1 mutant mice, a model of familial ALS, we investigated whether this kinase also contributed to the inclusions found in ALS patients and SOD1 mutant mice. Intense immunoreactivity for activated p38MAPK was observed in degenerating motor neurons and reactive astrocytes in ALS cases. The intracellular immunostaining for activated p38MAPK appeared in some neurons as filamentous skein-like and ball-like inclusions, with an immunohistochemical pattern identical to that of ubiquitin. Intracellular p38MAPK-positive aggregates containing ubiquitin and neurofilaments were also found in the spinal motor neurons of SOD1 mutant mice. Our observations indicate that activation of p38MAPK might contribute significantly to the pathology of motor neurons in ALS.     

Cholinergic function in lumbar aluminum myelopathy

To determine whether perikaryal neurofilamentous accumulation in cholinergic neurons is associated with a deficit in cholinergic function, we developed a new model of aluminum-induced neurofibrillary degeneration, referred to as focal lumbar aluminum myelopathy. The model is produced by direct intramedullary microinjection of AlCl3, which results in a characteristic neurological syndrome. Four weeks after injections, affected rabbits show extensive neurofilamentous lesions of both large and small neurons in the lumbar spinal cord, including a majority of anterior horn cells. These animals are capable of long-term survival. Posterior tibial nerve morphometry in these rabbits revealed no significant loss of myelinated fibers. Choline acetyltransferase (ChAT) activity in the sciatic nerve was decreased 39%, from 45.70 +/- 2.36 nmol ACh/hour/3-mm segment in acid-injected controls to 17.72 +/- 1.94 in aluminum-intoxicated rabbits. The rate of accumulation of ChAT activity proximal to a sciatic nerve ligature was significantly greater in the aluminum-treated rabbits, although the total amount of ChAT activity accumulating in a 24-hour period did not differ from controls. We conclude that aluminum-induced accumulation of neurofilaments in cholinergic perikarya is associated with a sharp decrease of ChAT activity in the axons of those cells and possibly with a compensatory increase in the rate of delivery of the enzyme.     

Ultrastructural, morphometric, and immunocytochemical study of anterior horn cells in mice with "wasted" mutation

Mice with the autosomal recessive gene "wasted" (wst/wst) manifest hindlimb paralysis and tremulousness, develop reduced secretory immune responses, and have abnormal DNA repair mechanisms. There is prominent vacuolar degeneration of neurons within anterior horns of the spinal cord and motor nuclei of the brainstem. A morphometric analysis of motor neurons in the spinal cord was performed on 2-hydroxyethyl methacrylate-embedded tissue from ten wst/wst mice, ten littermates (wst/+, +/+) without clinical deficits, and ten parental (+/+) control mice. Vacuolated neurons were present only in wst/wst mice (p = 0.0008). Fibrillary neurons were more numerous in the wst/wst mice than in littermates (p = 0.01) or controls (p = 0.007). The number of total or normal neurons did not differ significantly among the three groups. Volume measurements for normal, fibrillary, vacuolated, and total neurons were greater in wst/wst mice (p less than 0.008). Electron microscopic studies revealed vacuolar degeneration exclusively within neurons of wst/wst mice with the prominent accumulation of neurofilaments. Immunocytochemical staining of Araldite-embedded sections with monoclonal antibodies (MAb) to 68 kDa, 160 kDa, and 200 kDa neurofilament proteins showed prominent staining of vacuolated and fibrillary neurons in wst/wst mice exclusively with the MAb to 200 kDa neurofilaments. Dephosphorylation of tissue reduced the staining of 200 kDa neurofilaments in wst/wst mice. These studies suggest that phosphorylated neurofilaments may be important in events producing neuronal dysfunction. Therefore the "wasted" mutation may be an excellent model for the study of motor neuron disease.     

Immunocytochemical and ultrastructural studies of upper motor neurons in amyotrophic lateral sclerosis

Summary The pathological alterations in upper motor neurons were investigated in 27 cases of adult-onset sporadic amyotrophic lateral sclerosis (ALS). No signficant cytoskeletal alterations were found in the Betz cells of any of the cases except one, although cytoskeletal pathology was consistently present in lower motor neurons. The one case had severe circumscribed atrophy of the precentral gyrus and, microscopically, had argentophilic intracytoplasmic inclusions in Betz cells and other pyramidal neurons in the primary motor area as eell as in the lower motor neurons. Immunocytochemically these inclusions contained the epitope of phosphorylated neurofilament and ubiquitin and ultrastructurally consisted of granule-associated filaments with neurofilaments. This is the first demonstration of alterations of cytoskeleton and ubiquitination in the giant cells of Betz, an established subset of upper motor neurons in ALS. Thus, although uncommon, cytoskeletal changes can be found in upper motor neurons in some ALS cases.Supported in part by USPHS grants NS24453, HD03110 and ES01704     

Loss of neurofilaments in the neuromuscular junction in a rat model of proximal axonopathy

C. Soler‐Martín, Ú. Vilardosa, S. Saldaña‐Ruíz, N. Garcia and J. Llorens (2012) Neuropathology and Applied Neurobiology 38, 61–71 Loss of neurofilaments in the neuromuscular junction in a rat model of proximal axonopathy Aims: Rodents exposed to 3,3′‐iminodipropionitrile (IDPN) develop an axonopathy similar to that observed in amyotrophic lateral sclerosis motor neurones, in which neurofilaments accumulate in swollen proximal axon segments. This study addressed the hypotheses that this proximal axonopathy is associated with loss of neurofilament proteins in the neuromuscular junctions and a progressive loss of neurofilaments advancing in a distal‐proximal direction from the distal motor nerve. Methods: Adult male Long‐Evans rats were exposed to 0 or 15 mM of IDPN in drinking water for 1, 3 or 5 weeks, and their distal axons and neuromuscular junction organization studied by immunohistochemistry. Quantitative data were obtained by confocal microscopy on whole mounts of the Levator auris longus. Results: Muscles showed no change in the distribution of acetylcholine receptor labelling in the neuromuscular junctions after IDPN. In contrast, the amount of neurofilament labelling in the junctions was significantly reduced by IDPN, assessed with two different anti‐neurofilament antibodies. In preterminal axons and in more proximal axon levels, no statistically significant reductions in neurofilament content were observed. Conclusions: The proximal neurofilamentous axonopathy induced by IDPN is associated with an abnormally low content of neurofilaments in the motor terminals, with a potential impact in the function or stability of the neuromuscular junction. In contrast, neurofilaments are significantly maintained in the distal axon.     

免疫介导的运动神经元损伤SMI-31表达的特征

目的观察实验性自身免疫性灰质病模型中上、下运动神经元磷酸化神经丝表达的特征。方法首先建立实验性自身免疫性灰质病模型,然后,通过免疫组化方法研究免疫介导的神经元损伤过程中运动神经元磷酸化神经丝(SMI-31)表达的变化。结果在免疫介导的神经元损伤过程中,大脑皮层及脊髓前角SMI-31免疫反应阳性的神经元数量与对照组相比明显增加(P=0.000)。结论神经丝重链的异常磷酸化可能在在免疫介导的神经元损伤过程中具有重要的作用。