RESUMEN
Expression of choline acetyltransferase, 200-kDa neurofilament protein, 28-kDa calbindin, neuronal NO synthase, caspase 3, and Ki-67 in the motor neurons of spinal cord segments T3-T5 in male C57Bl/6 mice after 30-day space flight in the Bion-M1 biosatellite was studied by immunohistochemical methods. Under conditions space flight, the size of motoneurons increased, the number of neurons containing choline acetyltransferase and neurofilaments, decreased, and the number of calbindin-positive neurons increased; motoneurons, expressing neuronal NO synthase and caspase 3 appeared, while Ki-67 was not detected. Fragmentation of neurons with the formation structures similar to apoptotic (residual) bodies was observed in individual caspase 3-positive motoneurons.
Asunto(s)
Neuronas Motoras/metabolismo , Vuelo Espacial , Médula Espinal/metabolismo , Ingravidez , Animales , Apoptosis/genética , Calbindinas/genética , Calbindinas/metabolismo , Caspasa 3/genética , Caspasa 3/metabolismo , Recuento de Células , Tamaño de la Célula , Colina O-Acetiltransferasa/genética , Colina O-Acetiltransferasa/metabolismo , Regulación de la Expresión Génica , Inmunohistoquímica , Antígeno Ki-67/genética , Antígeno Ki-67/metabolismo , Masculino , Ratones , Neuronas Motoras/química , Neuronas Motoras/patología , Proteínas de Neurofilamentos/genética , Proteínas de Neurofilamentos/metabolismo , Óxido Nítrico Sintasa de Tipo I/genética , Óxido Nítrico Sintasa de Tipo I/metabolismo , Médula Espinal/química , Médula Espinal/patologíaRESUMEN
The expression of choline acetyltransferase (ChAT), neurofilament (NF) protein 200 kDa, calbindin (CAB) 28 kDa, neuronal NO-synthase (nNOS), caspase 3, Ki-67 was studied in motor neurons from TIIITV segments of the spinal cord in C57/ BL6 male mice by immunohistochemical methods 12 h after a 30 days-long space flight on the Bion-M1 biosatellite. Mice living under standard vivarium conditions served as a control. The motoneurons of experimental animals demonstrated the reactive changes that were manifested by the increase of their size, decrease in the number of subpopulations expressing ChAT and NF, increase of subpopulations containing CAB, appearance of motor neurons expressing nNOS, caspase-3, and the absence of Ki-67. The lack of proliferating gliocytes, the preservation of nucleolar component indicate the absence of necrobiotic changes characteristic of necrosis. The cytoplasmic vacuolization was observed in thionine-stained CAB-immunoreactive neurons. The disintegration of motor neurons into fragments resembling the apoptotic bodies was observed in single cells that contained caspase-3.
Asunto(s)
Neuronas Motoras , Proteínas del Tejido Nervioso/metabolismo , Vuelo Espacial , Médula Espinal , Animales , Masculino , Ratones , Neuronas Motoras/metabolismo , Neuronas Motoras/patología , Médula Espinal/metabolismo , Médula Espinal/patologíaRESUMEN
UNLABELLED: Mice were exposed to 1 month of space flight on the Russian biosatellite BION-M1 to determine its effect on the expression of genes involved in the maintenance of the mouse brain dopamine system. The current article focuses on the genes encoding glial cell line-derived neurotrophic factor (GDNF) and cerebral dopamine neurotrophic factor (CDNF). Space flight reduced expression of the GDNF gene in the striatum and hypothalamus but increased it in the frontal cortex and raphe nuclei area. At the same time, actual space flight reduced expression of the gene encoding CDNF in the substantia nigra but increased it in the raphe nuclei area. To separate the effects of space flight from environmental stress contribution, we analyzed expression of the investigated genes in mice housed for 1 month on Earth in the same shuttle cabins that were used for space flight and in mice of the vivarium control group. Shuttle cabin housing failed to alter the expression of the GDNF and CDNF genes in the brain structures investigated. Thus, actual long-term space flight produced dysregulation in genetic control of GDNF and CDNF genes. These changes may be related to downregulation of the dopamine system after space flight, which we have shown earlier. © 2015 Wiley Periodicals, Inc. SIGNIFICANCE: Our results provide the first evidence of microgravity effects on expression of the GDNF and CDNF neurotrophic factor genes. A considerable decrease in mRNA level of GDNF and CDNF in the nigrostriatal dopamine system was found. Because both GDNF and CDNF play a significant role in maintenance and survival of brain dopaminergic neurons, we can assume that this dysregulation in genetic control of GDNF and CDNF genes in substantia nigra could be among the reasons for the deleterious effects of space flight on the dopamine system.
Asunto(s)
Encéfalo/metabolismo , Regulación de la Expresión Génica/fisiología , Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Factores de Crecimiento Nervioso/metabolismo , Ingravidez , Animales , Factor Neurotrófico Derivado de la Línea Celular Glial/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Factores de Crecimiento Nervioso/genética , ARN Mensajero/metabolismo , Vuelo Espacial , Factores de TiempoRESUMEN
Mice of C57BL/6J strain were exposed to 1-month spaceflight on Russian biosatellite Bion-M1 to determine the effect of long-term actual spaceflight on the expression of genes involved in the processes of neurogenesis and apoptosis. Specifically, we focused on the genes encoding proapoptotic factor BAX, antiapoptotic factor BCL-XL, brain-derived neurotrophic factor (BDNF) and BDNF receptors TrkB and p75. Spaceflight reduced the expression of the antiapoptotic BCL-XL gene in the striatum and hypothalamus, but increased it in the hippocampus. To estimate environmental stress contribution into spaceflight effects we analyzed spaceflight-responsive genes in mice housed for 1 month on Earth in the same shuttle cabins that were used for spaceflight, and in mice of the laboratory control group. It was shown that 1-month shuttle cabin housing decreased BCL-XL gene expression in the striatum but failed to alter BCL-XL mRNA levels in the hippocampus or hypothalamus. Spaceflight failed to alter the expression of the proapoptotic BAX gene in all investigated brain structures, although the insignificant increase of the BAX mRNA level in the hippocampus of spaceflight mice was found. At the same time, shuttle cabin housing produced insignificant decrease in BAX gene expression in the hippocampus. In contrast to the BCL-XL gene, genes encoding BAX, BDNF as well as TrkB and p75 receptors did not respond to 30-day spaceflight. Thus, long-term spaceflight (1) did not affect the expression of genes encoding BDNF as well as TrkB and p75 receptors, (2) produced dysregulation in genetic control of the neuronal apoptosis, (3) implicated BCL-XL as the risk factor for spaceflight-induced behavioral abnormalities.
Asunto(s)
Encéfalo/metabolismo , Vuelo Espacial , Animales , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Expresión Génica , Vivienda para Animales , Masculino , Ratones Endogámicos C57BL , ARN Mensajero/metabolismo , Receptor trkB/metabolismo , Receptores de Factor de Crecimiento Nervioso/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Estrés Fisiológico/fisiología , Proteína X Asociada a bcl-2/metabolismo , Proteína bcl-X/metabolismoRESUMEN
Mice were exposed to 1 month of spaceflight on Russian biosatellite BION-M1 to determine its effect on the expression of key genes in the brain dopamine (DA) and serotonin (5-HT) systems. Spaceflight decreased the expression of crucial genes involved in DA synthesis and degradation, as well as the D1 receptor. However, spaceflight failed to alter the expression of tryptophan hydroxylase-2, 5-HT transporter, 5-HT1A, and 5-HT3 receptor genes, though it reduced 5-HT2A receptor gene expression in the hypothalamus. We revealed risk DA and 5-HT neurogenes for long-term spaceflight for the first time, as well as microgravity-responsive genes (tyrosine hydroxylase, catechol-O-methyltransferase, and D1 receptor in the nigrostriatal system; D1 and 5-HT2A receptors in the hypothalamus; and monoamine oxidase A (MAO A) in the frontal cortex). Decreased genetic control of the DA system may contribute to the spaceflight-induced locomotor impairment and dyskinesia described for both humans and rats.
Asunto(s)
Conducta Animal/fisiología , Encéfalo/metabolismo , Dopamina/metabolismo , Serotonina/metabolismo , Vuelo Espacial , Animales , Regulación de la Expresión Génica/fisiología , Humanos , Masculino , Ratones Endogámicos C57BL , Receptor de Serotonina 5-HT2A/metabolismo , TiempoRESUMEN
Chronic action of gravity force of 2 G on pre- and postnatal rats up to day 75 of postnatal development gave rise to ultrastructural deviations in the somatosensory cortex (SSC) suggesting higher afferentation to SSC as compared with their counterparts at 1 g, more intensive synaptic transmission, afferent input by dendrites and neurons functioning with more frequent interneuronic contacts, glia activation and increased blood supply that altogether pointed to a permanent impact of elevated extero- and proprioceptive input throughout the time of SSC formation.
Asunto(s)
Dendritas/ultraestructura , Hipergravedad , Neuroglía/ultraestructura , Neuronas Aferentes/ultraestructura , Corteza Somatosensorial/ultraestructura , Animales , Animales Recién Nacidos , Comunicación Celular , Femenino , Desarrollo Fetal , Feto , Masculino , Embarazo , Ratas , Corteza Somatosensorial/irrigación sanguínea , Transmisión SinápticaRESUMEN
Electron microscopic study of left ventricle cardiomyocytes and quantitative analysis of their mitochondriom was performed in rats exposed to tail-suspension, as a model of weightlessness effects, to artificial gravity produced by intermittent 2G centrifugation and a combination of these effects. It was found that the cardiomyocytes ultrastructure changed slightly after tail-suspension and after intermittent 2G influence, as well as under a combination of these effects. However, the number of intermitochondrial junctions increased significantly in the interfibrillar zone of cardiomyocytes under a combination of tail-suspension and intermittent 2G influence, which agrees with the cell hypertrophy described earlier.
Asunto(s)
Gravitación , Ventrículos Cardíacos/citología , Miocitos Cardíacos/fisiología , Miocitos Cardíacos/ultraestructura , Simulación de Ingravidez , Animales , Centrifugación , Masculino , Microscopía Electrónica , Mitocondrias/ultraestructura , Ratas , Ratas WistarRESUMEN
Rat globin peptides alkylated by sulfur mustard on amino-acid residues C-126, C-93 and E-27 with MH+ 1444.62 Da, 1561.66 Da, 1676.78 Da, respectively, were concentrated using metal-affinity chromatography on Cu2+. The peptides were received by trypic digestion after in vitro incubation of rat globin with 60 microM HD. Aklylated peptide with MH+ 1444.62 Da is the most sensitive biomarker, which can be concentrated from globin trypic digest, incubated with 3 microM sulfur mustard.
Asunto(s)
Cromatografía de Afinidad/métodos , Hemoglobinas/química , Hemoglobinas/aislamiento & purificación , Gas Mostaza/química , Alquilación , Animales , RatasRESUMEN
Electron microscopy examination of layers III-IV in the somatosensory cortex of rat's brain following 5- and 33-day and repeated 5-day exposure to 2 G revealed ultrastructural changes in dendritic spines, synapses, axon terminals and nervous cell body suggesting their functional activation and increase of the afferent input from hindlimb mechanoreceptors Hypertrophy of the acicular apparatus (AA) due to hypergravity, growth of AA destruction as a result of 33-day exposure and its ample evidence after repeated 5-day exposure lead to the conclusion that AA ultrastructure can be used for assessing afferent input into the brain cortex of animals exposed in a changed field of gravity.
Asunto(s)
Espinas Dendríticas/ultraestructura , Hipergravedad/efectos adversos , Terminales Presinápticos/ultraestructura , Corteza Somatosensorial/patología , Sinapsis/ultraestructura , Vías Aferentes/patología , Animales , Peso Corporal , Masculino , Mecanorreceptores/patología , Microscopía Electrónica , Ratas , Ratas Wistar , Factores de TiempoRESUMEN
Quantitative cytochemical and morphometric methods were used to investigate cytochrome oxidase activity and sizes of bodies and nuclei of Purkinje's cells in the medical nodulus and upper central lobule of the vermis obtained from rats sacrificed in 5-6 hours of landing after the 14-day SLS-2 mission of NASA space "shuttle" Columbia (STS-58). The reduced cytochrome oxidase activity was explained by suppression of the functional activity of Purkinje's cells in microgravity. Results of the investigations suggest weakening of the regulatory effect of the vermis Purkinje's cells on giant neurons of the dorsocaudal segment of Deiters nucleus. They also strengthen the earlier hypothesis that space flight decays the inhibitory effect of nodulus Purkinje's cells on the medial vestibular nucleus for the reason of change in the "velocity storage" in mammals during and after flight.
Asunto(s)
Cerebelo/ultraestructura , Propiocepción/fisiología , Células de Purkinje/ultraestructura , Trastornos Somatosensoriales/patología , Vuelo Espacial , Núcleo Vestibular Lateral/ultraestructura , Ingravidez/efectos adversos , Animales , Cerebelo/enzimología , Cerebelo/fisiopatología , Modelos Animales de Enfermedad , Complejo IV de Transporte de Electrones/metabolismo , Estudios de Seguimiento , Inmunohistoquímica , Masculino , Microscopía Electrónica , Células de Purkinje/enzimología , Ratas , Ratas Sprague-Dawley , Trastornos Somatosensoriales/enzimología , Trastornos Somatosensoriales/fisiopatología , Núcleo Vestibular Lateral/metabolismo , Núcleo Vestibular Lateral/fisiopatologíaRESUMEN
Actin-binding protein alpha-actinin-4 is a member of spectrin super family. It is located in the cytoplasm and in the nucleus. However, nuclear functions of alpha-actinin-4 are still not clear. In this study, we analyzed composition of nuclear protein complexes associated with alpha-actinin-4 in A431 cells. Using 2D electrophoresis, we have determined that about 50 different proteins may be associated with nuclear alpha-actinin-4. Using mass-spectrometry, we analyzed major proteins of these complexes. beta-Actin, alpha- and beta-tubulins, ribonucleoprotein A2/B1, which regulates splicing and is associated with beta-actin, peroxiredoxin-1, which is involved in oxidative stress, and glycolytic enzyme D-3-phosphoglycerate dehydrogenase were identified by MALDI-TOF. Detection of these proteins in nuclear complexes with alpha-actinin-4 may suggest that alpha-actinin-4 is involved in transcription and splicing. Presence of beta-actin in the investigated complexes was confirmed by tandem mass-spectrometry (MALDI-TOF-TOF). Immunoprecipitation of nuclear proteins with antibodies against alpha-tubulin confirmed association of alpha-actinin-4 with alpha-tubulin in the protein complex. Nuclear alpha-actinin-4 constitutes of 105 KDa fullsize isoform and two truncated isoforms of 65 and 75 kDa, whereas only the truncated isoform have been found in nuclear complexes with alpha-tubulin. These data suggest that alpha-actinin-4 is associated with a number of different nuclear protein complexes which may carry out different functions in the cell nucleus.
Asunto(s)
Actinina/metabolismo , Núcleo Celular/metabolismo , Proteínas Nucleares/metabolismo , Actinina/química , Línea Celular Tumoral , Electroforesis en Gel Bidimensional , Humanos , Inmunoprecipitación , Peso Molecular , Proteínas Nucleares/química , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Espectrometría de Masas en TándemRESUMEN
The quantitative cytochemical and morphometrical techniques applied in the experiment with 24-d tail-suspension of rats demonstrated a decrease of cytochrome oxidase activity and downsizing of Purkinje's cell bodies in the proprioceptive cerebellum (cerebellar vermis upper central lobule), as well as a decrease of cytochrome oxidase activity in Purkinje's cells in the vestibular cerebellum (nodulus). The observed suppression of the Purkinje's cells functional activity indicates reductions in the proprioceptive and vestibular afferent inputs to these cells during simulation of the microgravity effects in rats. Intermittent exposure to hypergravity (2 G, one hour a day) prevented the decreases in cytochome oxidase activity in Purkinje's cells of both the proprioceptive and vestibular cerebella of tail-suspended rats suggesting a nearly same level of functioning as in the vivarium controls.
Asunto(s)
Complejo IV de Transporte de Electrones/metabolismo , Hipergravedad/efectos adversos , Propiocepción/fisiología , Células de Purkinje/patología , Animales , Modelos Animales de Enfermedad , Suspensión Trasera , Masculino , Células de Purkinje/enzimología , Ratas , Ratas WistarRESUMEN
Cytochrome oxidase activity as well as neurons' body and nuclei sizes were measured in the spinal L5 ganglia receiving the hindlimb afferent input during primary and repeated 14-d tail-suspension of rats. The measurements were performed using the quantitative cytochemical and morphometric techniques. The animals were suspended 30 days and returned to vivarium. Thirty day later, they were suspended again, together with a group of intact rats, this time for 14 days. Primary 14-day suspension reduced significantly the cytochrome oxidase activity in small, middle and large neurons (cross-section area of bodies less than 800, 800-2000 microm2 and more than 2000 microm2, respectively) and yielded a trend-like diminution of the nerve cells bodies and nuclei. The postponed repeated suspension, unlike the primary 14-d one, resulted in a substantial downsizing of bodies and nuclei of middle neurons suggesting a more dramatic hypofunction and a more dramatic decrease of afferent input. However, the cytochrome oxidase activity was not suppressed considerably in small and middle neurons which might be explained by initiation of the afferent input recovery.
Asunto(s)
Ganglios Espinales/fisiología , Vértebras Lumbares , Simulación de Ingravidez , Animales , Complejo IV de Transporte de Electrones/metabolismo , Estudios de Seguimiento , Ganglios Espinales/citología , Masculino , Ratas , Ratas WistarRESUMEN
The cytochrome oxidase activity, sizes of bodies, nuclei, and nucleoli of alpha-motoneurons from the L5 anterior horns were investigated in rats once or repeatedly suspended by tails to model the effects of microgravity. Rats were suspended 30 days, then held in vivarium 30 days w/o any behavior restriction and suspended once again 14 days simultaneously with rats that had not been suspended before. The first-time 14-d suspension reduced the cytochrome oxidase activity as well as sizes of bodies and nuclei in alpha-motoneurons which pointed to hypofunctioning of these nervous cells. Repeated (14-d) suspension after the 30-day maintenance in vivarium decreased the alpha-motoneurons parameters much less significantly implying mild hypofunction and a faster adaptation of L5 alpha-motoneurons to microgravity modeled again after a long period of recess.
Asunto(s)
Neuronas Motoras/patología , Nervios Espinales/patología , Simulación de Ingravidez , Ingravidez/efectos adversos , Animales , Modelos Animales de Enfermedad , Estudios de Seguimiento , Suspensión Trasera/métodos , Masculino , Ratas , Ratas Wistar , Nervios Espinales/fisiopatologíaRESUMEN
Laser cooling and crystallization of electron-ion plasma is studied using the Brownian dynamics simulation technique and taking into consideration the interaction of ions with the electron subsystem. It has been shown that the nonlinear dependence of laser friction force on the velocity of ions has to be taken into account in order to simulate in an adequate manner the cooling dynamics and obtain a correct estimate for minimum temperatures. It has been found that times required for formation of an ordered ionic structure can be much longer than the typical plasma cooling time.
RESUMEN
Electron microscopy was used to study structural elements of the vestibular afferent input to the cerebellar nodulus Purkinje's cells--terminals of mossy fibers and granular cells in the granular layer and parallel fibers and Purkinje's cell dendrites in the molecular layer in rats decapitated in 2-3 hours and 9 days after the 9-day space flight aboard NASA shuttle Columbia (STS 40, SLS-1 mission). Analysis of the revealed ultrastructural changes on the base of morphofunctional correlations leads to the following conclusions: 1) space flight induced a prolonged reduction in vestibular input to most of the mossy fiber terminals and nodulus Purkinje's cells; 2) within the initial hours of recovery the vestibular input to a part of mossy fiber terminals and granular cells was increasing due to elevation of the sensitivity of vestibular receptors in microgravity; 3) regain of the vestibular input to Purkinje's cells after space flight is hampered by structural, as a result of microgravity effects, and also functional, developing shortly after space flight, impediments, and 4) in 9 d after landing the vestibular input to Purkinje's cells was almost normal. The observed reduction in the vestibular input to the nodulus Purkinje's cells during and after the spaceflight microgravity is presumably the key to the mechanism altering the velocity storage in mammals in microgravity and on return from space flight.
Asunto(s)
Dendritas/ultraestructura , Microscopía Electrónica/métodos , Neuronas Aferentes/ultraestructura , Células de Purkinje/ultraestructura , Vuelo Espacial , Nervio Vestibular/ultraestructura , Animales , Estudios de Seguimiento , Masculino , Ratas , Ratas Sprague-Dawley , Factores de Tiempo , Ingravidez/efectos adversosRESUMEN
The neuromuscular junctions were investigated in m. soleus of rats subjected to a 3-month tail suspension simulating the microgravity effects. Electron microscopy analysis revealed some ultrastructural signs of atrophy, degeneration and adipose dystrophy of muscle fibers. The aggregate of these findings points to progressive atrophy in m. soleus, while ultrastructural changes in the neuromuscular synapses testify a reduced functional activity of the synapses and partial denervation of the muscle fibers which, probably, underlay the atrophic process in the muscle. Increases in the number of axon terminals found in some neuromuscular synapses as well as of synaptic vesicles in individual axon terminals are likely to reflect formation of a particularly active pool of spinal motoneurons at L5, possibly associated with the growth in the number of fast fibers resulted from transformation.
Asunto(s)
Neuronas Motoras/ultraestructura , Músculo Esquelético/inervación , Unión Neuromuscular/ultraestructura , Simulación de Ingravidez/efectos adversos , Animales , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Estudios de Seguimiento , Suspensión Trasera/efectos adversos , Suspensión Trasera/métodos , Masculino , Microscopía Electrónica , Músculo Esquelético/ultraestructura , Distrofia Muscular Animal/etiología , Distrofia Muscular Animal/patología , Terminales Presinápticos/ultraestructura , Ratas , Ratas Wistar , Vesículas Sinápticas/ultraestructura , Factores de Tiempo , Simulación de Ingravidez/veterinariaRESUMEN
Nineteen-day centrifugation of rats at 2 G and ensuing 30-d readaptation to 1 g caused changes in the somatosensory cortex (SSC) ultrastructure pointing to intensification of the afferent input and functional activity of SSC neurons during hypergravity, and recovery of these processes in the course of readaptation. Repeated 5-d centrifugation of the rats at 2 G produced changes in ultrastructure of SSC layers 3 and 4 evidencing a more effective cortex functioning aimed at facilitation of adaptation to hypergravity repeated after the lengthy delay.
Asunto(s)
Hipergravedad , Corteza Somatosensorial/ultraestructura , Vuelo Espacial , Adaptación Fisiológica , Animales , Axones/ultraestructura , Dendritas/ultraestructura , Masculino , Neuronas/ultraestructura , Ratas , Ratas WistarRESUMEN
By means of scanning electron microscopy the ultrastructure of ependyma was studied in the brain third ventricle of the rats repeatedly exposed to 14-day tail-suspension (TS). Animals were subjected to TS for 30 days, then readapted to horizontal position during 30 days and again, repeatedly subjected to TS for 14 days simultaneously with the rats which were in TS for the first time during 14 days. Repeated TS of rats, inspite of repeated redistribution of body liquid mediums in cranial direction, results in considerably less expressed destructive changes in ultrastructure of ependymocyte cilia, then after primary 14- and 30-day TS, showing much greater cerebrospinal fluid (CSF) outflow from brain ventricles into sagittal venous sinus at postponed for a long time, repeated simulation of weightlessness effects in comparison with CSF outflow at primery one.