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1.
Microglial cells are absent from the corpus callosum of newborn rats. In the hope of finding out when and how microglial cells appear with age, 3H-thymidine was given intraperitoneally as single or three shortly spaced injections to 5-day-old rats weighing about 15 g; and these animals were sacrificed at various time intervals from 2 hours to 35 days later. Pieces of corpus callosum were taken near the superior lateral angle of the lateral ventricles; and semithin sections were radioautographed and stained with toluidine blue. The corpus callosum of 5-day-old rats is composed of loosely arranged unmyelinated fibers and scattered cells. Among these cells, microglia are rare; there are a few astrocytes, many immature glial cells, rare pericytes, and 6-7% of phagocytic “ameboid cells” consisting of a few monocytes and many macrophages. In the animals sacrificed two hours after 3H-thymidine administration, label is present only in immature cells and “ameboid cells.” As time elapses and the fibers of corpus callosum become myelinated, oligodendrocytes and, later, microglial cells appear. At the age of 12 days, microglial cells are present in substantial number; and by 19 days, the number doubles to reach a plateau. Many of the new microglial cells are labeled, e.g., 78.1% in 12-day-old animals (7 days after 3H-thymidine administration). The labeled microglial cells must have come from the transformation of cells that acquired label early, that is, from the immature cells or the “ameboid cells.” The height of the peaks of labeling – 59.8% at nine days for immature cells and 77.8% at 12 days for “ameboid cells” – points to the latter as precursors of the highly labeled microglial cells. Furthermore, the “ameboid cells” disappear as microglial cells appear and there are transitional elements between these two cell types. Cell counts suggest that about a third of the “ameboid cells” transform into microglial cells, while the others degenerate and die. Thus, the microglial cells which appear in the corpus callosum during the first three weeks of life result from transformation of the “ameboid cells” – a group of macrophages showing various stages of transition from monocytes. As for the occasional microglial cell appearing after the third week or in the adult, they presumably come directly from monocytes. In either case, monocytes would be the intial precursors.  相似文献   

2.
The proliferation of glial cells outside the subependymal layer of the lateral ventricle as well as of endothelial cells was studied autoradiographically in the brain of the adult and untreated mouse. The double labeling method with 3H- and 14C-thymidine was applied in order to show experimentally the existence of a DNA synthesis phase (S phase) and to measure its duration. Adult mice received a first injection of 14C-thymidine, two or four hours later a second injection of 3H-thymidine and were sacrificed one hour after the last injection by perfusion fixation. Double layer autoradiographs were made from serial sections of the region from the corpus callosum/commissura anterior up to the corpus callosum/commissura fornicis ventralis in order to register purely 3H-, doubly 3H- and 14C-, and purely 14C-labeled nuclei. From the ratio of all 3H-labeled cells with and without 14C to the purely 3H-labeled cells a DNA synthesis phase of 9.4 ± 0.5 hours for glial cells and one of 11.0 ± 2.2 hours for endothelial cells was obtained. Based on the first appearance of labeled mitoses and labeled pairs of glial cells after injections of labeled thymidine the G2 phase was estimated to be < three hours and G2 + M about five hours. The duration of the measured S phase as well as the appearance of labeled mitoses about three hours after application of labeled thymidine are very similar to these cycle parameters in many other somatic cells in different kinds of animals. This has led to the conclusion that a well-defined DNA synthesis phase with doubling of the DNA content and a successive mitosis also exists in glial and endothelial cells of the adult mouse brain.  相似文献   

3.
The techniques of [3H]-thymidine radioautography and Cajal's gold stain for astrocytes were employed to compare the behavior of astrocytes and mononuclear leukocytes during repair of brain injury. In animals injected with [3H]-thymidine 1 day before inducing brain injury, large numbers of labeled mononuclear leukocytes were seen in the corpus callosum and cortical gray matter in the wound area at subsequent time intervals. Uninjured hemispheres showed a low frequency of labeled cells. The size of the population of labeled cells fluctuated with time and with type of injury (stab injury or tumor allograft), but was always much larger than the astrocyte population at the injury site. When the labeled cells were classified as to nuclear type, the subgrops also fluctuated with time and with the type of injury. In contrast, the gold-stained cell population remained stable with time and with both types of injury. There was no evidence of either deoxyribonucleic acid synthesis or migration. Injured hemispheres of animals injected with [3H]-thymidine as juveniles showed no migration of labeled cells to the region of hypertrophied astrocytes alongside a tumor transplant. Thus, the body's main cellular defense against brain injury appeared to be migration of mononuclear leukocytes into the wound area. Astrocytic response was limited to hypertrophy of those astrocytes already located near the wound.  相似文献   

4.
Strong labeling of the cells in the subependymal layer was produced by stereotaxic injection of 5 μCi of 3H-thymidine into the left lateral ventricle of the brain of one and a quarter month old rats weighing about 100 gm. These animals were sacrificed by glutaraldehyde perfusion from two hours to 21 days later. Blocks of corpus callosum with adjacent subependymal and ependymal layers were excised from the injected and non-injected sides, and embedded in Epon; 0.5 μ thick sections were radioautographed and stained with toluidine blue. In the subependymal region, on both injected and non-injected sides, there was an immediate uptake of label by many cells followed by an increase and later a decrease in the percent cells labeled. In the corpus callosum while at first the percent labeling of glial cells was rather low, it did increase slowly with time and, after seven days, exceeded that in the subependymal region. These results were interpreted as indicating that cells arising in the subependymal layer had migrated into the corpus callosum. Up to four days after injection, most of the label in corpus callosum was present in immature-looking cells resembling the cells of the subependymal layer and referred to as free subependymal cells. With time, the percent labeling decreased in these cells while increasing in some of the glial cells. A labeling peak was observed for light oligodendrocytes at four to seven days and for dark oligodendrocytes at 21 days, whereas labeling of medium shade oligodendrocytes occurred at intermediate times. The succession of labeling peaks indicated a sequence of development from free subependymal cells through light and medium shade to dark oligodendrocytes. Few astrocytes carried label at any time; those which did seemed to have arisen from the transformation of labeled free subependymal cells. Microglia were unlabeled at two hours, but their percent labeling was high at 4–14 days. While the labeling of other glial cells reflected their physiological behavior, the labeling of microglia was a consequence of the trauma produced by the injection 0f tracer into the ventricle. In conclusion, cells coming from the subependymal layer appear to migrate into the corpus callosum where, in 100 gm rats, many of them transform into oligodendrocytes and a few into astrocytes.  相似文献   

5.
Tritiated thymidine (3H-TdR) injected before a stab wound of the spinal cord or transection of the hypoglossal nerve has resulted in many labeled reactive cells in the CNS after injury, most of which have the ultrastructural features of microglia. To test for the possible origin of these labeled cells from monocytes, we examined them for the presence of sodium, fluoride- (NaF) sensitive non-specific esterase (NSE), an enzyme characteristic of monocytes. Some of the labeled cells in stab wounds had NaF-sensitive NSE, but no such cells were found in the nucleus of the injured hypoglossal nerve. To test for the possibility that the NSE-negative labeled cells had been labeled by reutilization of 3H-TdR, we used 125I-5-iodo-2'deoxyuridine (125I-UdR), a thymidine analogue with a much lower rate or reutilization, to label blood mononuclear cells prior to either a spinal cord stab wound or hypoglossal axotomy. The number of labeled cells was decreased in the spinal cord wound, but more than half were NSE-negative. No labeled blood mononuclear cells were found in the hypoglossal nucleus, although there was no decrease in the hyperplasia of unlabeled non-neuronal cells. When 125I-UdR was injected on the fourth day after hypoglossal axotomy, or when both 3H-TdR and 125I-RdR were injected simultaneously before hypoglossal axotomy, many labeled cells were found in the hypoglosaal nucleus, indicating that 125I-UdR can be used by the reactive cells and that it did not inhibit their proliferation. Therefore, the microglial cells that proliferate in response to peripheral nerve injury are not recently derived from any type of circulating large blood mononuclear cell. The most likely explanation for the presence of the 3H-TdR-labeled cells in the nucleus of the injured hypoglossal nerve in that they were proliferating intrinsic labeled by reutilization of 3H-TdR.  相似文献   

6.
The uptake and transport of γ-aminobutyric acid (GABA) by neurons in the cat dentate nucleus were studied using light microscopy autoradiography after injections of 3H-GABA into the nucleus. Injections of 3H-GABA were also made into the overlying cerebellar cortex to provide positive evidence for uptake of the label in each experiment. In autoradiographs where labeled neurons were observed in the cortex, 3H-GABA was also observed to be incorporated by some dentate neurons. Along the periphery of the injection sites in the dentate nucleus, some neuronal soma and their processes were very heavily labeled as indicated by the dense accumulation of autoradiographic silver grains overlying those neuronal elements. Immediately adjacent there were nonlabeled neurons which were quite conspicuous due to the paucity of silver grains overlying their cell bodies and processes. Labeled axons were also observed leaving the injected regions of the dentate nucleus. Some labeled fibers coursed from the lateral and ventrolateral edge of the nucleus into the corpus medullare and the white matter of individual cerebellar folia. These axons could not, however, be traced into the cortex. Other labeled axons projected from the ventromedial hilus of the dentate into the brachium conjunctivum. These results demonstrate an uptake and intraaxonal transport system for 3H-GABA within the cat dentate nucleus.  相似文献   

7.
To examine the fine structure of blood mononuclear cells in injured nervous tissue, mice were given repeated injections of 3H-thymidine with the last injection at least 16 hours before injury. Under ether anesthesia the animals either were given a stab wound to the spinal cord or had their left hypoglossal nerve transected. The animals were killed at 2, 4, 8, or 16 days after injury. Tissue sections containing the spinal cord wound or both hypoglossal nuclei were prepared for electron microscopic radioautography, and all labeled cells were photographed. About half the labeled cells in the injured hypoglossal nerves had nuclei with dark staining peripheral heterochromatin, dark cytoplasm with long cisternae of granular endoplasmic reticulum, and other ultrastructural features characteristic of the cells usually identified as microglia. The remaining labeled cells in the injured spinal cords were macrophages, fibroblasts, cells with pale nuclei, some of which contained cytoplasmic filaments, and vascular cells. Since uninjured nervous tissue has extremely few labeled cells and since 3H-thymidine should be available for only a short time following injection, most of the labeled cells in this experiment should be derived from blood mononuclear cells. However, the possibility is discussed that some or all of the labeled cells proliferating in response to the injury and labeled through reutilization of labeled DNA precursor material.  相似文献   

8.
[3H]Choline injected into the ventral lateral thalamic nucleus (VL) labeled cell bodies of the deep cerebellar nuclei and adjacent vestibular nuclei by retrograde axoplasmic transport. Injections in caudal and dorsal parts of VL labeled cells in ventral parts of the dentate nucleus and interpositus posterior nucleus. Injections in rostral and ventral parts of VL labeled cells in the interpositus anterior nucleus and dorsal parts of the dentate nucleus. A few labeled cell bodies were found throughout the rostrocaudal extent of the fastigial nucleus and in adjacent parts of the vestibular nuclei. A combined injection of [3H]choline and [3H]amino acids labeled cells in the deep cerebellar nuclei and axon terminals in layer I of the middle suprasylvian gyrus (areas 5, 7).  相似文献   

9.
10.
《Brain research》1985,335(2):237-243
[3H]Choline injected into the ventral lateral thalamic nucleus (VL) labeled cell bodies of the deep cerebellar nuclei and adjacent vestibular nuclei by retrograde axoplasmic transport. Injections in caudal and dorsal parts of VL labeled cells in ventral parts of the dentate nucleus and interpositus posterior nucleus. Injections in rostral and ventral parts of VL labeled cells in the interpositus anterior nucleus and dorsal parts of the dentate nucleus. A few labeled cell bodies were found throughout the rostrocaudal extent of the fastigial nucleus and in adjacent parts of the vestibular nuclei. A combined injection of [3H]choline and [3H]amino acids labeled cells in the deep cerebellar nuclei and axon terminals in layer I of the middle suprasylvian gyrus (areas 5, 7).  相似文献   

11.
Pregnant Sabra mice received 3 g phenobarbital (PhB)/kg milled food from gestation days 9 to 18 as their only food source; control female mice received milled food. All animals were divided into three groups and injected i.p. with a single dose of [H3]thymidine on gestation days (GD) 13, 15, or 17. The offspring survived until 50 days of age when they were anesthetized and perfused with 10% neurtral Formalin and the brains were removed and prepared for autoradiography. Matching sagittal sections of different offspring were selected for the study of the cerebellum, hippocampus, or cortex. The number of labeled Purkinje cells of the cerebellum was reduced 75% (P < 0.001) on GD 13 in experimental female, but not male offspring. The number of labeled cerebellar granule cells per section did not differ between groups. The hippocampus showed a 67% reduction in female offspring (P < 0.01) and a 51% reduction in male offspring. (P < 0.01) of labeled pyramidal cells per section on GD 13 after prenatal treatment of phenobarbital. As in the cerebellum, no deficits occurred in the hippocampal granule cells. In the cortex the drug decreased cell labeling 52% in female (P < 0.05) and 30% in male offspring (P < 0.05) per square millimeter on GD 13. Control groups demonstrated a gender difference in the prenatal labeling of cortical cells: male offspring had 46% more labeled cells per section (P < 0.01) on GD 13. A breakdown of the cortex into different regions showed that the greatest gender difference occurred in the deep strata (close to the corpus callosum) on GD 13. A 58% reduction in treated female (P < 0.001) and 43% reduction in treated male offspring (P < 0.001) was noted. The results suggest that phenobarbital induced alterations in the times of origin of neurons or in necrosis of recently formed neurons.  相似文献   

12.
Following morphine treatment, an autoradiographic study investigated the uptake of 3H-thymidine by the subependymal cells in the rat brain. 3H-thymidine was administered subcutaneously to adult, male Sprague-Daw-ley rats 30 minutes after saline or morphine (10 mg/kg) injection. The animals were sacrified 1 hour after 3H-thymidine administration. In some experiments the opioid antagonist, naloxone, was given alone 45 minutes before 3H-thymidine or 15 minutes before morphine treatment. Three areas of the subependyma were evaluated in terms of the percentage labeled cells and number of grains per nucleus, and a dorsal-to-ventral gradiant was described. Morphine treatment significantly increased the number of 3H-thymidine labeled subependymal cells and number of grains/nucleus within labeled cells. Examination of the distribution of grains/nucleus showed that morphine-treated animals had significantly more cells labeled with 30 or more grains than did saline-injected controls. Prior administration of naloxone blocked the increased 3H-thymidine uptake in morphine-treated animals but had no significant influence on cell proliferation when administered alone. The data are discussed in terms of morphine's possible dual influence on mechanisms which enhance cell transition from G to S phase and/or which accelerate DNA synthesis once these cells have entered the S phase of cell replication.  相似文献   

13.
The red nucleus (RN) has been widely used to study the formation and remodeling of synaptic connections during development and in post-lesion plasticity. Since glial cells are thought to contribute to synaptic plasticity, and information on functional properties of brain stem glia is missing, we analyzed voltage-gated ion channels as well as glutamate receptors expressed by glial cells of the RN. The patch-clamp technique was applied to identified cells in acute brain stem slices of 5- to 12-day-old rats. Based on their pattern of membrane currents, two types of glial cells could be distinguished. A first type was characterized by passive, symmetrical currents. The second population of cells, which was the focus of the present study, expressed a complex pattern of voltage-gated channels. These cells could be labeled with antibodies against glutamine synthetase and S100β, suggesting an astroglial origin. Depolarizing voltage steps activated transient and delayed rectified K+ currents as well as Na+ currents. In addition, a subset of cells expressed Ba2+ sensitive inward rectifier K currents activated by hyperpolarization. All “complex” glial cells analyzed possessed ionotropic glutamate receptors of the α-amino-3-hydroxy-5-methyl-4-isoxazoleprorionic acid (AMPA) subtype, while functional kainate and N-methyl-D-aspartate (NMDA) receptors could not be detected. Receptor activation blocked outward rectifying K+ currents, similar to previous observations in glial cells of the hippocampus and the corpus callosum. GLIA 19:234–246, 1997. © 1997 Wiley-Liss, Inc.  相似文献   

14.
Summary Cell proliferation in the brain of spontaneously hypertensive rats (SHR) and control Wistar rats of various ages was autoradiographically investigated using [3H]thymidine. The brain of SHR showed an increase in labeled cells. The increase of labeled cells was seen in the early stage of the development of hypertension when there were still no definite morphological changes in the cerebral vessel walls or brain parenchyma. The labeled cells tended to increase in number with the age of the animals. The distribution of these cells corresponded with areas of increased vascular permeability and cerebrovascular lesions, that is, water-shed regions. The labeled cells consisted of endothelial and adventitial cells of the intracerebral arterioles and pial arteries as well as glial cells. Arachnoid cells, subarachnoid cells, medial smooth muscle cells of the pial arteries were also labeled, though less intensely. The significance of labeled endothelial cells in the development of cerebrovascular changes and sequential parenchymal changes is discussed.  相似文献   

15.
Recently, both basic and clinical studies demonstrated that bone marrow stromal cell (BMSC) transplantation therapy can promote functional recovery of patients with CNS disorders. A non‐invasive method for cell tracking using MRI and superparamagnetic iron oxide (SPIO)‐based labeling agents has been applied to elucidate the behavior of transplanted cells. However, the long‐term safety of SPIO‐labeled BMSCs still remains unclear. The aim of this study was to investigate the short‐, middle‐ and long‐term safety of the SPIO‐labeled allogeneic BMSC transplantation. For this purpose, BMSCs were isolated from transgenic rats expressing green fluorescent protein (GFP) and were labeled with SPIO. The Na/K ATPase pump inhibitor ouabain or vehicle was stereotactically injected into the right striatum of wild‐type rats to induce a lacunar lesion (n = 22). Seven days after the insult, either BMSCs or SPIO solution were stereotactically injected into the left striatum. A 7.0‐Tesla MRI was performed to serially monitor the behavior of BMSCs in the host brain. The animals were sacrificed after 7 days (n = 7), 6 weeks (n = 6) or 10 months (n = 9) after the transplantation. MRI demonstrated that BMSCs migrated to the damage area through the corpus callosum. Histological analysis showed that activated microglia were present around the bolus of donor cells 7 days after the allogeneic cell transplantation, although an immunosuppressive drug was administered. The SPIO‐labeled BMSCs resided and started to proliferate around the route of the cell transplantation. Within 6 weeks, large numbers of SPIO‐labeled BMSCs reached the lacunar infarction area from the transplantation region through the corpus callosum. Some SPIO nanoparticles were phagocytized by microglia. After 10 months, the number of SPIO‐positive cells was lower compared with the 7‐day and 6‐week groups. There was no tumorigenesis or severe injury observed in any of the animals. These findings suggest that BMSCs are safe after cell transplantation for the treatment of stroke.  相似文献   

16.
Astrocytes are implicated in many aspects of brain function; however, it remains unclear whether astrocytes arise from a single cell lineage. It is therefore important to obtain new markers for the astrocyte cell lineage. We show that exogenously added UDP-galactose (UDP-Gal) can be used to metabolically label a subset of glial fibrillary acidic protein-positive (GFAP+) cells. UDP-Gal was incorporated into the cultured embryonic mouse brain slices in a time-dependent manner. Surprisingly, the transferred sugar moiety was no longer Gal but was mainly glucose. Most of the radioactivity was transferred to a polymer of glucose, most likely to be glycogen, and also to glucosyl ceramide. In the slice culture, the reaction products were distributed densely in the ventricular zone and also on process-like structures extending to the pial surface. In dissociation culture, UDP-Gal labeled some of the GFAP+ cells and some of the vimentin+ cells. Because radial glial cells (RGCs) contain glycogen and change from vimentin+ to GFAP+, it is strongly suggested that UDP-Gal labeled RGCs and their descendants. Only 27% of the GFAP+ cells were labeled with UDP-Gal, which suggests that only a subset of astrocytes are derived from RGCs and that there is a discrete group of GFAP+ cells that is not generated from RGCs. J. Neurosci. Res. 52:173–183, 1998. © 1998 Wiley-Liss, Inc.  相似文献   

17.
The distribution of specific [3H]hemicholinium-3 ([3H]HC-3) binding sites throughout the rat forebrain was studied by means of quantitative light microscopic autoradiography. Tissue sections were labeled with 2.5 nM[3H]HC-3, apposed to tritium-sensitive film for 2 months and analyzed by computer-assisted densitometry. Regions of intense [3H]HC-3 labeling include the caudate-putamen, nucleus accumbens, olfactory tubercle, amygdala, habenula and the granule cell layer of the dentate gyrus. Little or no specific binding was detected in the corpus callosum, a white matter region. This distribution of specific [3H]HC-3 binding sites is compatible with a selective labeling of central cholinergic nerve terminals.  相似文献   

18.
Murine RSV-M glioma cells were genetically labeled with a retroviral BAG vector carrying the Escherichia coli β-galactosidase gene. The X-gal-positive stable cell line RSV-M/BAG was obtained by the FDG-FACS method. To examine the behavior of glioma cells in the brain, we homografted RSV-M/BAG cells into the brain of C3H/HeN mice as cell suspensions. Individual grafted glioma cells were easily detected by histochemical staining for B-galactosidase (β-gal). Three days after grafting, the β-gal-positive cells were mainly found in the subependymal zone of the lateral ventricle. In addition, some solitary labeled cells were found at locations distant from the injection sites. On the seventh day after implantation, tumor masses were observed and graft-derived glioma cells were migrating bilaterally along the fibers in the corpus callosum. Other labeled cells extended into the brain parenchya via the perivascular (Virchow-Robin) spaces. Rapid and extensive migration of individual glioma cells was thus clearly demonstrated by intracerebral transplantation of RSV-M/BAG cells. © 1994 Wiley-Liss, Inc.  相似文献   

19.
The distributions of ganglionar cell bodies, specifically labeled with3H-5-HT, were studied in light microscope autoradiographs of the cat nodose ganglion. The size, number and localization of labeled cells were examined under different experimental conditions: after in vitro incubation of the ganglion with3H-5-HT and after retrograde transport of3H-5-HT injected into the nucleus of the solitary tract (NST) which receives primary visceral sensory projections from nodose ganglia cells of the vagal nerve.Following incubation of the nodose ganglia with a low concentration of3H-5-HT (10−6 M), some ganglionar cell bodies took up and retained the tracer. In both the right and left ganglia, they were significantly smaller in size than the unreactive neurones. The mean diameter of their perikaryon was 36.97±0.52 μm, compared with 45.76±0.87 μm in unreactive neurones. About 600 labeled cell bodies were counted in each ganglion, corresponding to 2–3% of the total nodose ganglion cell population. These reactive neurones were not localized in one particular area of the ganglia, but scattered throughout both of them. Following bilateral or unilateral microinjections of3H-5-HT in the NST, retrogradely labeled cell bodies were observed, 24 h later, in the nodose ganglia. Their mean diameter was estimated to be 36.14±0.69 μm and they represented approximately 2% of the total ganglion cell population. As in in vitro experiments, the labeled cells were not grouped in any particular region of the ganglion.These experiments show that the distribution of both populations of labeled cells, observed under these conditions, are comparable. On an anatomical and quantitative basis one may reasonably suppose that the perikaryal or terminal uptakes concern the same neuronal population.  相似文献   

20.
In teleosts, cerebellar efferent neurons, known as eurydendroid cells, are dispersed within the cerebellar cortex rather than coalescing into deep cerebellar nuclei. To clarify their morphology, eurydendroid cells were labeled retrogradely by biotinylated dextran amine injection into the base of the corpus cerebelli. Labeling allowed the cells to be classified into three types-fusiform, polygonal, and monopolar-depending on their somal shapes and numbers of primary dendrites. The fusiform and polygonal type cells were distributed not only in the Purkinje cell layer but also in the molecular and granule cell layers. The monopolar type cells were distributed predominantly in the Purkinje cell layer of the ventrocaudal portion of the corpus cerebelli. These results suggest that there are some functional differences between these eurydendroid cell types. The eurydendroid cells were double-labeled by retrograde labeling and immunohistochemistry using specific antibodies against GABA, aspartate, and zebrin II. No GABA-like immunoreactivity was detected in the retrogradely labeled eurydendroid cells. About half of retrogradely labeled cells were immunoreactive to the anti-aspartate antibody, suggesting that some eurydendroid cells utilize aspartate as a neurotransmitter. Zebrin II reacts with cerebellar Purkinje cells but left all retrogradely labeled neurons nonreactive, although some of these were surrounded by immunopositive fibers. This relationship between the eurydendroid and Purkinje cells is similar to that between the deep cerebellar nuclei and Purkinje cells in mammals.  相似文献   

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