Acta neuropathologica
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Acta neuropathologica · Jun 2002
Neuronal degeneration and glial cell-responses following trimethyltin intoxication in the rat.
Trimethyltin (TMT) preferentially induces neuronal changes in the hippocampus and pyriform cortex. In the present study we investigated the time course of microglial and astroglial responses associated with neurodegeneration after the administration of TMT (i.p. 9 mg/kg or 12 mg/kg body weight) in the rat. At a dosage of 9 mg/kg TMT, neurodegeneration was clearly demonstrated in the CA1 and CA3 regions of the hippocampus as argyrophilic (dark) neurons by day 4 using the Gallyas-Braak (G-B) impregnation method that has been shown to be sensitive and specific for neurodegeneration. ⋯ The number of reactive microglia considerably decreased to the resting state by day 14, while hypertrophied astrocytes were still prominent in the CA3 up to day 21. With the high dose of TMT, granule cells in the dentate gyrus and CA1 and CA3 pyramidal cells were significantly impregnated. After TMT treatment, accompaning neurodegeneration we observed early response of microglia and prolonged activation of astrocytes, suggesting an individual role of glial cells in maintenance and repair of damaged neurons following brain injury.
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Acta neuropathologica · May 2002
Neuronal nitric oxide synthase (nNOS) immunoreactivity in the spinal cord of transgenic mice with G93A mutant SOD1 gene.
Immunohistochemical and quantitative analyses were used to examine the evolution of neuronal nitric oxide synthase (nNOS) with time in spinal motor neurons of transgenic mice with a G93A mutant Cu/Zn superoxide dismutase (SOD1) gene. Specimens from age-matched non-transgenic wild-type mice served as controls. In the controls, the anterior horn including the anterior horn neurons was not immunostained for nNOS. ⋯ At the age of 35 weeks (end stage), neuronal loss of the anterior horn cells was severe, and nNOS-positive anterior horn neurons and cord-like swollen axons in the anterior horns were less prominent compared to those at the age of 32 weeks (33.8%), but many reactive astrocytes were immunostained for nNOS. Thus, nNOS immunoreactivity in the anterior horn neurons is observed as early as the presymptomatic stage and varies with the progression of the disease. The selective localization of positive nNOS immunoreactivity in the anterior horn neurons and degenerated ones in particular, and swollen proximal axons suggests that nNOS immunoreactivity may be involved in the degeneration of anterior horn neurons in this SOD1 transgenic mouse model.
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Acta neuropathologica · Nov 2001
Quantitative pathology of cutaneous nerve terminal degeneration in the human skin.
Pathological diagnosis of neuropathy has traditionally depended on ultrastructural examinations of nerve biopsy specimens, particularly for sensory neuropathies affecting unmyelinated and small-myelinated nociceptive nerves. These sensory nerves terminate in the epidermis of the skin, and the pathology of neuropathy usually begins from nerve terminals. We investigated the feasibility of diagnosing small-fiber sensory neuropathy by evaluating cutaneous innervation. ⋯ Ocular nerve fiber densities were significantly correlated with IENF densities as measured by the image analysis system (r=0.99, P<0.0001). Dermal nerve fibers of neuropathic patients either disappeared or became degenerated. These findings were consistent with the notion of early terminal degeneration in neuropathy, and will facilitate quantitative interpretation of epidermal innervation in human neuropathy.
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Acta neuropathologica · Aug 2001
White matter preservation after spinal cord injury in ICAM-1/P-selectin-deficient mice.
We have previously demonstrated that mice deficient in ICAM-1 and P-selectin (ICAM-1/PS-/-) have improved functional recovery after spinal cord injury (SCI), compared to injured controls. In this study the spinal cords from wild-type and ICAM-1/PS-/- mice were evaluated histopathologically 14 days after severe compression-type SCI. Following injury there was an atrophy of the spinal cord. ⋯ Quantitation of iba1 immunohistochemistry revealed that microglial reaction was significantly suppressed in the mutant animals. Astroglial reaction, visualized by GFAP immunostaining, did not differ between groups. Our results indicate that ICAM-1 and P-selectin are involved in autodestructive events provoked by the initial injury but the precise underlying mechanisms remain obscure.
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Acta neuropathologica · Jul 2001
Same axonal regeneration rate after different endoneurial response to intraneural glycerol and phenol injection.
Glycerol (an atoxic alcohol) and phenol (a toxic monohydroxybenzene) are currently used as neurolytic blocking agents to relieve pain or spasticity. In the present study we compared the endoneurial response of anhydrous glycerol and 7% phenol-aqua after intraneural injection into rat sciatic nerve, using electron microscopy and immunohistochemical stainings. Despite the wide use of these drugs, a systematic morphological study of their action has not been done. ⋯ The delayed invasion of macrophages after phenol injection may be due to occluded vessels or may be related to the denaturing effect of phenol on the proteins needed for macrophage attraction. Despite the rapid invasion of macrophages after glycerol injection axonal regeneration was delayed when compared to that seen after traumatic axotomy, but the axonal regeneration occurred at the same time in both experimental groups. Thus, the results suggest that after chemical axonotmesis the axonal regeneration rate is not dependent on the macrophage invasion rate alone and that other endoneurial changes also play a role.