OBJECTIVETo observe the pathological changes of axonal injury in a rat model of experimental allergic encephalomyelitis (EAE).

METHODSWith HE, luxol fast blue and Bielschowsky staining, the expression of APP, MBP, SMI-32 and MBP in the brain and spinal cord of EAE rats using double-labeling indirect immunofluorescence.

RESULTSExtensive cuffing lesions of inflammatory cell infiltrations were found in the brain and spinal cord of the rats, accompanied by multiple lesions of demyelination, axonal disarrangement with vesicular loss. SMI-32 staining identified numerous nonphosphorylated neurofilament, indicating the presence of axonal injury. Axonal oval bodies formed by APP accumulation were found in the white matters of the spinal cord 14 days after EAE, suggesting that neuraxial damage occurred in the early stage of EAE which was not synchronous with myelin loss.

CONCLUSIONDifferent levels of inflammation occur in different stages of EAE, and inflammatory cell infiltration is the most obvious at the peak of EAE. Axonal injury occurs in the early stage of EAE and progresses over the entire disease course.

Animals ; Axons ; pathology ; Brain ; pathology ; Encephalomyelitis, Autoimmune, Experimental ; pathology ; Female ; Rats ; Rats, Wistar ; Spinal Cord ; pathology

OBJECTIVETo study the pathological changes in the non-myelin sheath by observing histological damages to the neurofilament protein and apoptosis of neurons in rats with experimental autoimmune encephalomyelitis (EAE).

METHODSForty-eight Wistar rats were randomly divided into two groups: control and EAE (24 rats in each group). Behavioral changes were observed. Inflammation reactions and demyelination were observed by hematoxylin eosin staining and LOYEZ staining.The level of neurofilament was detected by immunohistochemistry. Apoptosis of the neuron in the spinal cord was detected by TUNEL.

RESULTSBehavioral and histological results confirmed that the model of EAE rats was prepared successfully. In the EAE group, typical morphological features of axonal damage (sparsed axonal density, axonal distortion, axonal transection and even axonal disappearance) were found from the seventh day after immunization and the morphological changes were the most obvious on the fourteenth day. Neurofilament density in the EAE group was significantly lower than in the control group (P<0.01) at 7, 14 and 21 days after immunization. The neuronal apoptosis index in the EAE group at 7, 14 and 21 days after immunization was significantly higher than in the control group (P<0.01).

CONCLUSIONSIn addition to inflammatory demyelination, axonal damage and neuronal apoptosis can be observed in the early stage of EAE. Pathological changes may be associated with neurological dysfunction.

Animals ; Apoptosis ; Axons ; pathology ; Encephalomyelitis, Autoimmune, Experimental ; pathology ; psychology ; Female ; Immunohistochemistry ; Myelin Sheath ; pathology ; Neurofilament Proteins ; analysis ; Neurons ; pathology ; Rats ; Rats, Wistar ; Spinal Cord ; pathology

OBJECTIVETo study the effects of heat shock preconditioning on the expression of heat shock protein-70 (HSP70) and apoptosis of the neuron in experimental autoimmune encephalomyelitis (EAE) rats.

METHODSThirty-six Wistar rats were randomly divided into control, EAE and heat shock preconditioning groups (n=12 each). The EAE animal model was induced with guinea pig myelin basic protein. Heat shock preconditioning was performed 24 hrs prior to the EAE model inducement. No treatment was done in the control group. The neurological signs were observed after immunization. The spinal cords were removed and stained with hematoxylin and eosin. HSP70 was detected by immunohistochemistry. Apoptosis of the neuron was measured by TUNEL.

RESULTSHeat shock preconditioning significantly alleviated clinical signs and neuronal injury. HSP70 expression in the heat shock preconditioning group was significantly higher than in the untreated EAE group (21.08 +/- 0.87 vs 10.17 +/- 0.51; P < 0.01). Heat shock preconditioning suppressed apoptosis of the neuron compared with the EAE group (apoptosis rate: 21.92 +/- 1.00% vs 58.92 +/- 1.67%; P < 0.01).

CONCLUSIONSHeat shock preconditioning might improve the neurological outcome in EAE rats, possibly through the induction of HSP70 synthesis and the reduction of apoptosis of the neuron in spinal cords.

Animals ; Apoptosis ; Bone Marrow ; pathology ; Encephalomyelitis, Autoimmune, Experimental ; pathology ; therapy ; Female ; Guinea Pigs ; HSP70 Heat-Shock Proteins ; biosynthesis ; Hot Temperature ; Male ; Neurons ; pathology ; Rats ; Rats, Wistar

An experimental allergic encephalomyelitis was induced by bovine myelin basic protein (MBP) and bovine galactocerebroside (GC) on male guinea pigs. Animals were divided into five experimental and one control groups. Among the five experimental groups, three were inoculated with 75 micrograms, 150 micrograms and 300 micrograms of MBP, respectively, to see the dose dependency of demyelination. The fourth group was inoculated with mixture of 75 micrograms of MBP and 180 micrograms of GC and the fifth group with 180 micrograms GC. All inocula was injected intradermally in emulsion state mixed with equal amount of complete Freund adjuvant. Control group was injected with adjuvant only. Clinical symptoms began to appear from 15th day after inoculation and animals were sacrificed on maximum neurologic deficit or 4 to 5 days after the onset of symptoms. Demyelination was observed in 6 out of 8 animals inoculated with MBP/GC mixture, while only 3 out of 24 animals inoculated with various dosage of MBP showed demyelination. The difference was statistically significant. Serum antibodies to MBP and GC were measured by ELISA method. All of the eight animals inoculated with MBP/GC mixture and two animals inoculated with GC had low titer of anti-GC antibodies, while all animals inoculated with MBP, MBP alone or MBP/GC mixture, had high titer of anti-MBP antibodies. Therefor it is concluded that the demyelination is augmented by GC and is not significantly dose-dependent on MBP.
Animals ; Autoantibodies/*immunology ; Central Nervous System/*immunology/pathology ; Cerebrosides/*immunology ; Dose-Response Relationship, Drug ; Encephalomyelitis, Autoimmune, Experimental/*metabolism/pathology ; Galactosylceramides/*immunology ; Guinea Pigs ; Male ; Myelin Basic Protein/*immunology

An experimental allergic encephalomyelitis was induced by bovine myelin basic protein (MBP) and bovine galactocerebroside (GC) on male guinea pigs. Animals were divided into five experimental and one control groups. Among the five experimental groups, three were inoculated with 75 micrograms, 150 micrograms and 300 micrograms of MBP, respectively, to see the dose dependency of demyelination. The fourth group was inoculated with mixture of 75 micrograms of MBP and 180 micrograms of GC and the fifth group with 180 micrograms GC. All inocula was injected intradermally in emulsion state mixed with equal amount of complete Freund adjuvant. Control group was injected with adjuvant only. Clinical symptoms began to appear from 15th day after inoculation and animals were sacrificed on maximum neurologic deficit or 4 to 5 days after the onset of symptoms. Demyelination was observed in 6 out of 8 animals inoculated with MBP/GC mixture, while only 3 out of 24 animals inoculated with various dosage of MBP showed demyelination. The difference was statistically significant. Serum antibodies to MBP and GC were measured by ELISA method. All of the eight animals inoculated with MBP/GC mixture and two animals inoculated with GC had low titer of anti-GC antibodies, while all animals inoculated with MBP, MBP alone or MBP/GC mixture, had high titer of anti-MBP antibodies. Therefor it is concluded that the demyelination is augmented by GC and is not significantly dose-dependent on MBP.
Animals ; Autoantibodies/*immunology ; Central Nervous System/*immunology/pathology ; Cerebrosides/*immunology ; Dose-Response Relationship, Drug ; Encephalomyelitis, Autoimmune, Experimental/*metabolism/pathology ; Galactosylceramides/*immunology ; Guinea Pigs ; Male ; Myelin Basic Protein/*immunology

Multiple sclerosis (MS) is a neuroinflammatory demyelinating disease, mediated by pathogenic T helper 17 (Th17) cells. However, the therapeutic effect is accompanied by the fluctuation of the proportion and function of Th17 cells, which prompted us to find the key regulator of Th17 differentiation in MS. Here, we demonstrated that the triggering receptor expressed on myeloid cells 2 (TREM-2), a modulator of pattern recognition receptors on innate immune cells, was highly expressed on pathogenic CD4-positive T lymphocyte (CD4⁺ T) cells in both patients with MS and experimental autoimmune encephalomyelitis (EAE) mouse models. Conditional knockout of Trem-2 in CD4⁺ T cells significantly alleviated the disease activity and reduced Th17 cell infiltration, activation, differentiation, and inflammatory cytokine production and secretion in EAE mice. Furthermore, with Trem-2 knockout in vivo experiments and in vitro inhibitor assays, the TREM-2/zeta-chain associated protein kinase 70 (ZAP70)/signal transducer and activator of transcription 3 (STAT3) signal axis was essential for Th17 activation and differentiation in EAE progression. In conclusion, TREM-2 is a key regulator of pathogenic Th17 in EAE mice, and this sheds new light on the potential of this therapeutic target for MS.
Animals ; Humans ; Mice ; CD4-Positive T-Lymphocytes/pathology* ; Cell Differentiation ; Encephalomyelitis, Autoimmune, Experimental/metabolism* ; Mice, Inbred C57BL ; Multiple Sclerosis ; Th1 Cells/pathology*

Melatonin (N-acetyl-5-methoxytryptamine), a pineal neurohormone, is a hydroxyl radical scavenger and antioxidant, and plays an important role in the immune system. We studied the effect of exogenous melatonin on the pathogenesis of experimental autoimmune encephalomyelitis (EAE). EAE was induced in Lewis rats by immunization with rat spinal cord homogenates. Subsequent oral administration of melatonin at 5 mg/kg significantly reduced the clinical severity of EAE paralysis compared with administration of the vehicle alone (p<0.01). Infiltration of ED1 macrophages and CD4 T cells into spinal cords occurred both in the absence and presence of melatonin treatment, but melatonin-treated rats had less spinal cord infiltration of inflammatory cells than did the control group. ICAM-1 immunoreactivity in the blood vessels of EAE lesions was decreased in melatonin-treated rats compared to vehicle-treated rats. These findings suggest that exogenous melatonin ameliorates EAE via a mechanism involving reduced expression of ICAM-1 and lymphocyte function associated antigen-1a in autoimmune target organs.
Animals ; Encephalomyelitis, Autoimmune, Experimental/*immunology/prevention & control ; Female ; Immunohistochemistry ; Intercellular Adhesion Molecule-1/analysis/*immunology ; Male ; Melatonin/administration & dosage/*physiology ; Rats ; Rats, Inbred Lew ; Spinal Cord/chemistry/pathology

OBJECTIVETo explore the sensitivity of magnetic resonance contrast agent ultrasmall superparamagnetic iron oxide (USPIO) enhancement scan in detecting experimental allergic encephalopathy (EAE) lesions and the change of magnetic transfer of USPIO enhancement lesions in the animal model of EAE.

METHODSThe routine T1-weighted imaging, T2-weighted imaging, three dimensional T1 magnetic transfer, three dimensional T1 no magnetic transfer, Dimeglumine Gadopentetate injection (Gd-DTPA) enhancement, and USPIO enhancement scan were performed in 11 EAE rats and 10 control rats respectively. The sensitivity of USPIO and Gd-DTPA enhancement in detecting the lesions in EAE rats was calculated. Magnetic transfer ratio (MTR) of USPIO enhancement area for the first time in EAE rats and MTR of the same area of the last scan were calculated respectively. HE and myelin staining of brain tissues were performed.

RESULTSNo abnormally enhanced lesions were showed in EAE rats' brain in Gd-DTPA enhancement scan, while abnormally enhanced lesions were showed in 11 EAE rats' brain in USPIO enhancement scan. The MTR value of USPIO enhancement area for the first time was significantly different from MTR of the same area of the last scan in EAE rats (P < 0.05). Inflammation cells and demyelination lesions were found in USPIO enhancement area histopathologically. There were no positive findings in control rats.

CONCLUSIONSThe sensitivity of USPIO enhancement scan in detecting EAE lesions was high. Magnetic transfer imaging, together with USPIO enhancement scan, was helpful to determine the features of the EAE lesions.

Animals ; Contrast Media ; Dextrans ; Encephalomyelitis, Autoimmune, Experimental ; diagnosis ; pathology ; Female ; Guinea Pigs ; Image Enhancement ; methods ; Magnetic Resonance Imaging ; methods ; Magnetite Nanoparticles ; Random Allocation ; Rats ; Rats, Inbred Lew

OBJECTIVETo study the therapeutic efficacy of baicalin and its effect on apoptosis of inflammatory cells in spinal cords in Wistar rats with autoimmune encephalomyelitis (EAE).

METHODSForty-four rats were randomly divided into four groups: normal control group (control, n=10), EAE group (n=12), and two intervention groups with dexamethasone (DXM) or baicalin. Seven days after immunization, the two intervention groups were injected intraperitoneally with DXM (1 mg/kg) and baicalin (200 mg/kg) for 1 week, respectively. The spinal cords were removed 14 days after immunization, and stained with hematoxylin and eosin. MBP expression in spinal cords was detected by immunohistochemistry. The apoptosis of inflammatory cells in spinal cords was detected by TUNEL.

RESULTSThe weight gain rate in the untreated EAE and the DXM or baicalin intervention groups were significantly lower than that in the control group (P<0.05). The weight gain rate in the baicalin intervention group was significantly higher than that in the untreated EAE and the DXM intervention groups (P<0.05). The scores of neurological function in the two intervention groups were significantly higher than that in the untreated EAE group (P<0.05). DXM or baicalin treatment significantly increased the MBP expression compared with the untreated EAE group (P<0.05). The apoptosis of inflammatory cells increased more in the DXM and the baicalin intervention groups compared with the untreated EAE groups (P<0.05).

CONCLUSIONSBaicalin has protective effects against EAE in rats. It can promote the apoptosis of inflammatory cells in spinal cords.

Animals ; Apoptosis ; drug effects ; Dexamethasone ; therapeutic use ; Encephalomyelitis, Autoimmune, Experimental ; drug therapy ; pathology ; Female ; Flavonoids ; pharmacology ; therapeutic use ; In Situ Nick-End Labeling ; Rats ; Rats, Wistar

Intermediate filaments, including nestin and vimentin, are found in specific cell types in central nervous system (CNS) tissues, particularly immature glial cells and multipotent progenitor cells. In the present study, the expression patterns of nestin and vimentin in the spinal cords of rats with experimental autoimmune encephalomyelitis (EAE) and the response of cells containing filaments against acute autoimmune injury were examined by immunohistochemistry. Nestin immunostaining was only weakly detected in vascular endothelial cells but not in any cell types in the spinal cord in normal and adjuvant-immunized rats. At the peak stage of EAE, nestin-immunoreativity was recognized in some astrocytes in the gray matter and white matter. Vimentin was immunopositive in some astrocytes and macrophages in EAE lesions, while vimentin was normally detected in ependymal cells of central canals in the rat spinal cords.We postulate that normal animals may contain multipotent progenitor cells in the spinal cord parenchyma as well as in the subpial lesion and ependyma. Multipotent progenitor cells may activate to transform into necessary cells, including neurons, astrocytes or oligodendrocytes, depending on CNS needs. Appropriate control of progenitor cells in the injured CNS is an alternative choice for CNS remodeling.
Animals ; Encephalomyelitis, Autoimmune, Experimental/*metabolism/pathology ; *Gene Expression Regulation ; Intermediate Filament Proteins/*metabolism ; *Nerve Tissue Proteins ; Rats ; Rats, Inbred Lew ; Spinal Cord/cytology/*metabolism/pathology ; Stem Cells/cytology ; Vimentin/*metabolism