Induced NG2 expressing microglia in the facial motor nucleus after facial nerve axotomy.

Chondroitin sulfate proteoglycan (NG2) expressing cells, ubiquitously distributed in the CNS respond to injured or diseased neurons; however, their behaviors toward injured neurons have remained to be fully explored. In the present study, along with astrocytic and microglial responses, NG2 expressing cells reacted swiftly and robustly in the facial motor nucleus (FMN) subjected to axotomy. With time, hypertrophic NG2 expressing cells gradually adhered to and enwrapped the axotomized motoneurons. Tight encapsulations around axotomized motoneurons were eventually formed at 7, 14, and 28 days after axotomy. NG2 positive processes appeared to interpose between synapsin-1 immunoreactive nerve terminals and surfaces of axotomized motoneurons. Double labeling results showed that NG2 expressing cells encapsulating axotomized facial motoneurons were mainly microglia marked by OX42 and lectin; only a few of them were positive to platelet-derived growth factor-alpha receptor and none of them positive to ED-1. No Rhodamine particle was detected in the FMN ipsilateral to axotomy after venous injection of the particles. The results suggest that activated microglia in lesioned FMN were induced to express NG2 molecules. It is concluded that axotomized FMN showed two types of NG2 expressing cells namely constitutive NG2 cells and induced-NG2 expressing microglia.

Differential expression of cytokines in the rat heart in response to sustained volume overload.

OBJECTIVE: The present study aimed to investigate whether sustained volume overload is capable of inducing persistent upregulation of cardiac cytokines including tumor necrosis factor alpha (TNF)-alpha, interleukin (IL)-1beta, interleukin (IL)-6 and transforming growth factor (TGF)-beta(1). METHODS AND RESULTS: Volume overload-induced heart hypertrophy in rats was established by aortacaval fistula, and the cardiac cytokines were measured in the myocardium from 1 to 4 weeks after operation. In the post-fistula rats, cardiac IL-1beta and IL-6 gene and protein levels were upregulated throughout the time of measurement. Immunohistochemistry demonstrated that IL-1beta and IL-6 immunoreactive cells were widely distributed in the myocardium in the earlier time intervals, and mainly localized in the regions close to the endocardium in the later time intervals. The cardiac IL-1beta immunoreactive cells were mainly localized in the blood vessels whereas the IL-6 positive cells were composed of non-myocytes and cardiomyocytes. TGF-beta(1) positive staining was increased in the myocardium up to 3 weeks after aortacaval fistula and then decreased to basal levels thereafter. In contrast to the activation of cardiac IL-1beta and IL-6 in response to volume overload, TNF-alpha expression appeared unaltered in response to sustained volume overload in the transcription and protein levels. CONCLUSION: The results of the present study indicate that sustained volume overload is capable of inducing persistent upregulation of some cardiac cytokines. In addition, the differential expressions of TNF-alpha, IL-1beta and IL-6 suggest that the induction of IL-6 and IL-1beta is independent of TNF-alpha mediated pathways in this animal model.

Cognitive impairment in sporadic ALS: a pathologic continuum underlying a multisystem disorder.

BACKGROUND: Traditionally considered a motor neuron-selective disorder, the clinical manifestations of ALS can include a frontotemporal dementia. Although the pathologic substrate of cognitive impairment remains to be defined, the presence of ubiquitin-immunoreactive (Ub+) intraneuronal inclusions in cortical regions has been suggested to constitute a pathologic marker of this process. METHODS: The authors compared the neuropathological features of four cognitively impaired patients with ALS, four cognitively intact patients with ALS, and four neurologically normal patients. The extent and load of Ub+ neuronal inclusions, Ub+ dystrophic neurites, and superficial linear spongiosis (SLS) was determined among a number of cortical, hippocampal, and subcortical regions. RESULTS: Although Ub+, alpha-synuclein-negative, and tau-negative neuronal inclusions were observed in both cognitively impaired and cognitively intact patients with ALS, their density and extent was greater among the former, with the difference greatest in the cingulate gyrus. Ub+ neurites were observed in a similar distribution. Only the presence of SLS, affecting the first and second cortical layers, reliably distinguished between the cognitively impaired and cognitively intact ALS subpopulations. In three of four cognitively impaired patients with ALS, SLS was associated with transcortical microglial activation, in the absence of detectable differences in astrocytosis, density of calbindin or parvalbumin neurons, or optical density of synaptophysin and SNAP-25. CONCLUSIONS: Although intraneuronal Ub+ inclusions and dystrophic neurites are observed in both ALS subpopulations, the presence of cognitive impairment was associated with a greater distribution and load of both neuropathologic features, suggesting a disease continuum. Moreover, cognitive impairment was uniformly associated with superficial linear spongiosis, a pathologic feature common to several forms of frontotemporal dementia.

Characterization of neuronal intermediate filament protein expression in cervical spinal motor neurons in sporadic amyotrophic lateral sclerosis (ALS).

Because transgenic mice expressing an altered stoichiometry of neurofilament proteins develop a motor neuron degeneration associated with neurofilamentous aggregate formation similar to that found in amyotrophic lateral sclerosis (ALS), we studied the expression of intermediate filament proteins in sporadic ALS. Archival cervical spinal cord paraffin-embedded sections from 11 disease and 11 control cases were studied by either in situ hybridization using 35S-labeled riboprobes or immunohistochemically using specific antibodies for the individual neurofilament subunit proteins, alpha-internexin, nestin, peripherin, vimentin, beta-actin, or Talpha1-tubulin. Median NFL, alpha-internexin, and peripherin steady-state mRNA levels were significantly reduced in the lateral motor neuron cell column (p < 0.05) of ALS cases, while neither NFM nor NFH mRNA levels were altered. ALS cases demonstrated an elevation of beta-actin mRNA levels (p < 0.01) with no increase in Talpha1-tubulin mRNA levels. No motor neuronal expression of nestin or vimentin was observed. Ubiquitin-immunoreactive perikaryal aggregates were immunoreactive for NFH or beta-actin, but not for peripherin, alpha-internexin, vimentin, or nestin. In contrast, neuroaxonal spheroids were strongly immunoreactive for NFH and peripherin, but not for beta-actin, alpha-internexin, vimentin, or nestin. These findings suggest that the stoichiometry of cytoskeletal protein expression in ALS spinal motor neurons is significantly altered in a pattern conducive to the formation of neurofilamentous aggregates.

Motor neuronal death in sporadic amyotrophic lateral sclerosis (ALS) is not apoptotic. A comparative study of ALS and chronic aluminium chloride neurotoxicity in New Zealand white rabbits.

Whether diseased motor neurones in sporadic amyotrophic lateral sclerosis (ALS) die via apoptosis is unknown. Because this relates primarily to difficulties in utilizing post-mortem tissue from end-stage disease, motor neurone degeneration in ALS spinal cord was compared with that of a model of a chronic motor neurone degeneration. Degenerating motor neurones in ALS, identified by ubiquitin immunoreactivity, did not demonstrate the morphological characteristics of apoptosis and were not c-Jun immunoreactive or TUNEL positive. A temporal analysis of spinal motor neurone death in the chronic AlCl3 neurotoxicity model of motor neurone degeneration was also undertaken. AlCl3 was administered intracisternally every 4 weeks and, at intervals of 51, 107, 156 and 267 days, evidence of apoptosis was sought by morphology, TUNEL hybridization or DNA laddering. Double-labelling immunostudies were also performed with antibodies to either c-Jun, ubiquitin or high molecular weight neurofilament (NFH) with TUNEL hybridization. Although significant neurone loss was evident, apoptosis was not found. These studies demonstrate a lack of apoptosis in ALS spinal motor neurones and suggest that this observation does not relate to the utilization of post-mortem tissue in which apoptotic neurones may have been lost.

A morphological analysis of the motor neuron degeneration and microglial reaction in acute and chronic in vivo aluminum chloride neurotoxicity.

The monthly intracisternal inoculation of aluminum chloride (AlCl3) to young adult New Zealand white rabbits induces motor neuron degeneration marked by intraneuronal neurofilamentous aggregates similar to that observed in amyotrophic lateral sclerosis (ALS). However, in contrast to ALS, this process occurs in the experimental paradigm in the absence of a glial response. In addition, whereas ALS is a fatal disorder, the cessation of aluminum exposure leads to both clinical and neuropathological recovery. Because microglia can influence neuronal regeneration, we have examined the effect of both acute and chronic aluminum exposure on microglial activation in vivo. We have studied microglial morphology in young adult New Zealand white rabbits receiving either single (1000 microg) or repeated sublethal (100 microg monthly) intracisternal inoculums of AlCl3. In addition, rabbits receiving 1000 microg AlCl3 inoculums were studied following an unilateral sciatic axotomy 48 h prior to the AlCl3 exposure. Our studies demonstrate that microglial activation in vivo is inhibited by AlCl3 exposure, and that a correlation exists between the extent of microglia suppression and the potential for recovery. This suggests that microglial activation is an important determinant of neuronal injury.

Microglia responses in the CNS following sciatic nerve transection in C57BL/Wld(s) and BALB/c mice.

The present study employed C57BL/Wld(s) mice to investigate whether a delay in microglia reaction would occur similar to the delay that occurs in macrophage response after sciatic neurectomy. The results were compared with control BALB/c mice. The observations showed that in both strains of mice there was no delayed microglia response around lesioned motoneurons and around the central processes of the dorsal root ganglion cells after sciatic neurectomy in the adult. The increased Mac-1 staining appeared as early as 1 day postoperation (dpo). This indicates that microglial cells and macrophages respond to different signals generated by neurectomy. In both strains of mice, the number of microglia in the neonate was much less than that in the adult and the increase in Mac-1 staining was detectable only at 3 dpo in both strains of mice. A significant loss of motoneurons was detected after sciatic neurectomy in the neonate. However, there were no significant differences in the mean percentages of motoneuron loss between the two strains of mice at 5, 10, and 15 dpo. It is surmised that the lack of an adequate number of mature microglia in the neonates and their tardy expression of CR3 antigenicity may contribute to the motoneuron loss.

Do microglial cells have a neuroprotective function?

To explore the possible neuroprotective role of microglia after a peripheral nerve lesion, the present study used athymic mice shown to have a lower number of microglia to highlight some functions of microglia not normally obvious in animals with a normal number of such cells. Observation of semithin sections showed that unoperated 5-day-old athymic mice had a significant lower number of microglial cells around sciatic motoneurons, compared to their BALB/c littermates. After right sciatic nerve cut at mid-thigh level, motoneuron loss occurred faster at 5 and 10 days after operation in neonatal athymic mice than BALB/c mice. The motoneuron loss by 15 days after nerve cut was, however, the same in both strains of mice. Microglial reaction after sciatic neurectomy, as revealed by Mac-1 immunohistochemistry, was obviously less in intensity and number in athymic mice than in BALB/c mice. The results indicated a neuroprotective function of microglia, which, when not present in adequate numbers, could result in a faster motoneuron death. The study also showed that while microglia were reduced in number in athymic mice, there was no significant difference in the number of astrocytes and oligodendrocytes in the spinal cord of the athymic mice, compared to that in BALB/c mice. This indicates that the development of astrocytes and oligodendrocytes in the spinal cord may not be affected by a reduced number of microglia.

Motoneuronal death without expression of NADPH-diaphorase activity after sciatic nerve cut in 5-day-old mice.

In BALB/c mice, the number of sciatic motoneurons lost was statistically insignificant whether the nerve was cut at one (P1) or five days (P5) of age. Although the motoneurons showed intense NADPH-d staining after sciatic nerve cut at P1, they were NADPH-d negative when the nerve was cut at P5. The present study casts doubt on a neurodestructive role of NO in the sciatic motoneurons after axotomy at P1.

Macrophage and microglial cell response after common peroneal nerve cut and crush in C57BL/6J mice.

The present study using Mac-1 immunohistochemistry for the detection of macrophages and microglial cells, has investigated the signals for macrophage recruitment in the peripheral nerve fibres and dorsal root ganglia, and microglial cell activation in the dorsal and ventral horns of the spinal cord, at different periods after a right common peroneal (CP) nerve cut or crush in 86 C57BL/6J mice. Though a previous study has demonstrated a delayed regeneration of the peripheral sensory but not the motor fibres in this strain of mice, the present study could not demonstrate a corresponding delay in macrophage recruitment in the L4-L6 dorsal root ganglia and microglial cell activation in the dorsal and ventral horns of the corresponding segments of the spinal cord. In fact, macrophage recruitment and microglial cell activation appeared a short time after the nerve lesion and peaked at 5 days post-operation then subsequently declined. Microglial cells, however, became reactivated at 20-30 days after CP nerve cut, perhaps because of the presence of newly degenerated fibres. In contrast to the above observation, there was no exuberant macrophage recruitment or microglial cell reaction during the period when the majority of the regenerated fibres were detected in the distal segment of the crushed nerve.

[7 elements in patients with heart diseases and their relationship with blood pressure and biochemical target].

The trace elements Zn, Cu, Fe, and ordinary elements K, Na, Ca, Mg in serum of 711 patients with heart disease (HD) were determined with GGX-II atomic absorption spectrophotometer and flame photometer. It was found that the contents of K, Ca/Mg in HD were significantly lower than those in the control, while the content of Na, Mg, Zn, Fe, and Zn/Cu, Na/K were significantly higher than those in the control. There was a significantly negative correlation between K, Ca/Mg and blood pressure (BP), between Zn/Cu and HDL-ch, and a significantly positive correlation between Na, Zn, Fe, Zn/Cu, Na/K and BP, between Fe and Hct, between Zn/Cu and Hct, TG, VLDL-ch.