Numerical Density Of Neurons Research Articles

3-acetylpyridine induced behavioral dysfunction and neuronal loss in the striatum and hippocampus of adult male rats

3-acetylpyridine (3-AP) is a neurotoxin that is known to mainly affect the inferior olivary nucleus (ION) in the brain stem. Although several studies have explored the effect of this neurotoxin, still further investigation is required to understand the impact of this toxin on different parts of the brain. In this research, two groups of rats were studied, the 3-AP-treated and the control groups. Behavioral, stereological, and immunohistochemical analyses were performed. The locomotor activity of the 3-AP-treated rats decreased whereas their anxiety levels were higher than in normal controls. Also, memory performance was impaired in animals in the 3-AP group. Microscopic observations showed a decline in the numerical density of neurons in the hippocampus and striatum along with gliosis. Although this toxin is used to affect the ION, it exerts a neurotoxic effect on different brain regions.

Changes in the cerebral cortex and thyroid in the simulation of cerebral hypoperfusion and its combination with physical exercise

Cerebral hypoperfusion, as the main mechanism of age-associated diseases, is widespread, which leads to decreased work capacity in the most qualified segment of employees. The study aimed to analyze compensatory and adaptive reactions of the cerebral cortex, thyroid gland, and blood in cerebral hypoperfusion and its combination with short-term physical activity. Chronic cerebral hypoperfusion was modeled by permanent bilateral occlusion of the common carotid arteries. The study included 280 rats, of which 112 were subjected to daily short-term swimming as a model of rehabilitation measures. On days 1, 6, 8, 14, 21, 28, 35, 60, and 90 after surgery, the animals were subjected to the Morris water maze and open field tests. Histological sections of the brain and thyroid gland were examined. The concentrations of the active products of thiobarbituric acid, nitrites, and L-arginine in blood plasma were measured. The results showed that changes in the cerebral cortex and thyroid gland in the cerebral hypoperfusion model were characterized by a general stage: days 18, hypothyroid condition and death of cortical cells, cerebral hemispheres, predominantly neurons; weeks 23, stabilization, transition to the euthyroid condition, accompanied with thyrocyte desquamation, folliculogenesis, perifollicular hemocapillaries fullness, decreased functional activity of neurons, and astrocyte activation; weeks 45, incomplete adaptation, which is characterized by neurons approaching the vessels of the hemocirculatory channel and satellites sinking into the cytoplasm of neurons. Mosaicism of thyroid blood filling was also observed. After 3 months, degenerative changes in the cells of the cerebral cortex of the cerebral hemispheres appear, including a decrease in the numerical density of neurons and immunoreactive cells of glial fibrillar acid protein and a hyperthyroid state with signs of decompensation: plasmorrhagia and desquamation of the thyroid epithelium. Daily 15-min exercise with cerebral hypoperfusion demonstrated a neuroprotective effect, slowed down the progression of hypoxic and neurodegenerative changes, and reduced the concentration of nitrites and malondialdehyde in the blood and the levels of neuronal nitric oxide synthase in immunoreactive neurons.

Exosomes derived from human placental mesenchymal stem cells in combination with hyperbaric oxygen synergically alleviates spinal cord ischemia-reperfusion injury

Spinal cord ischemia-reperfusion injury (IR) is a terrible non-traumatic injury that occurs after abdominal aortic occlusion and causes serious damage to neurological function. Several treatment strategies have been suggested for IR, but they were not unable to effectively improve these conditions. Herein we investigated whether exosomes derived from human placental mesenchymal stem cells (hpMSCs-Exos) in combination with hyperbaric oxygen (HBO) could alleviate injury and promote recovery in IR rats. Eighty male Sprague-Dawley rats were randomly allocated into five equal groups. In addition to the control group that only underwent laparotomy, IR animals were planned into four groups as follows: IR group; IR-Exos group; IR-HBO group; and IR-Exos + HBO group. Neurological function evaluated before, 6 h, 12 h, 24 h, and 48 h after injury. After the last neurological evaluation, tissue samples were obtained for stereological, biochemical, and molecular assessments. Our results indicated that the neurological function scores (MDI), the numerical density of neurons, the levels of antioxidative factors (GSH, SOD, and CAT), and anti-inflammatory cytokine (IL-10) were considerably greater in treatment groups than in the IR group, and these changes were more obvious in the IR-Exos + HBO ones. This is while the numerical density of glial cells, the levels of an oxidative factor (MDA) and inflammatory cytokines (IL-1β, TNF-α, and IL-18), as well as the expression of an apoptotic protein (caspase-3) were meaningfully decreased in treatment groups, especially IR-Exos + HBO group, compared to the IR group. Generally, it was found that co-administration of hpMSCs-Exos and HBO has synergistic neuroprotective effects in the rats undergoing IR.

Morphofunctional Changes in Neurons, Glial Cells and Synapses in the Sensorimotor Cortex after Severe Traumatic Brain Injury

The aim of the study was to investigate morphofunctional modifications in neurons, glial cells and synaptic terminals in the sensorimotor cortex of the brain in rats after severe traumatic brain injury (STBI).Material and methods. STBI simulation in white rats (main group, n=30) was performed on a device with a special shock mechanism. Intact animals (n=6) were included in the control group. The sensorimotor cortex (SMC) of the brain in rats was studied histomorphologically on sections stained with hematoxylin and eosin and thionin according to Nissl. Synaptophysin and GFAP were detected immunohistochemically, then morphometry was performed. On serial frontal sections of the SMC, neurons, neuroglia, and interneuronal synapses were studied in animals of the control group and in animals exposed to STBI in 1, 3, 7, 14, and 30 days after STBI simulation. The number density of neurons, neuroglia, and synaptic terminals was determined per a unit area of the section of layers I (terminals only), III, and V of the cerebral SMC. Statistical hypotheses were tested using nonparametric methods in the Statistica 10.0 program.Results. In animals of the control group, typical normochromic pyramidal neurons predominated, synaptic terminals were clearly verified; this was combined with unaltered neuropil. In animals exposed to STBI, there were signs of tinctorial, hydropic, dehydration and necrobiotic changes in neurons, reactive astrogliosis, fields of "loss" of neurons appeared; the overall numerical density of neurons and synapses decreased. The maximally increased content of pycnomorphic neurons was detected in 1 day after STBI (in layer III of the SMC, by 11.6%; in layer V of the SMC, by 18.5%). The peak in the number density of shadow cells and hyperchromic non-wrinkled neurons was noted in 3 days. The numerical density of synaptic terminals in different layers of the SMC decreased by 1.5-2 times. The altered balance of the destruction and restoration processes of the synaptic pool after STBI was evidenced by statistically significant data on the decreased and increased numerical density of terminals during 30 days of the study. There was no complete recovery of the studied parameters of neurons and synapses to control values within 30 days.Conclusion. The SMC of the brain in rats remains functioning after STBI; this occurs in the context of long-term preservation of reversibly and irreversibly damaged neurons, reactive neurogliosis, and permanent reorganization of interneuronal relationships due to activated reparative neuro- and synaptic plasticity. The data obtained will specify reorganization of the components of various neuronal complexes of the SMC (layers I, III, and V) after STBI.

Structural and Functional Reorganization of the Sensorimotor Cortex During Ligation of the Common Carotid Arteries (Experimental Study)

Aim of the study. To explore the structural and functional changes of neurons, glial cells, and synaptic terminals in layers I, III, and V of the sensorimotor cortex (SMC) of the rat brain after bilateral common carotid artery ligation (CCAL).Material and methods. Incomplete cerebral ischemia was simulated by irreversible bilateral CCAL (2-vessel model of global ischemia without hypotension) on white rats (n=36). Comparative evaluation of the studied SMC structures was performed in the control group (intact rats, n=6) on days 1, 3, 7, 14, and 30 (n=30) after CCAL. Nissl, hematoxylin-eosin staining, and immunohistochemical reactions for NSE, MAP-2, p38, GFAP, and IBA1 were used. Numerical density of pyramidal neurons, astrocytes, oligodendrocytes, microglial cells, and relative area of p38-positive material (synaptic terminals) were determined. Statistical hypotheses were tested using nonparametric methods with Statistica 8.0 software.Results. After CCAL, the number of degenerative neurons in rat brain SMCs increased. The peak of numerical density of unshrunken neurons was detected after day 1. Later, the numerical density of hyperchromic unshrunken neurons decreased, while that of shrunken neurons increased. These parameters did not reach the control values. The changes in SMC neurons were accompanied by an increase in the numerical density of microglial cells after day 1 and its subsequent decrease. Immunohistochemistry for IBA1 revealed signs of microglial cell activation such as change in shape and loss of processes. Maximum increase in the SMC density of oligodendrocytes was observed on day 7, and that of astrocytes on day 14 after CCAL. The maximum number of NSE-positive neurons occurred on day 1 after CCAL. There was a significant decrease in the number of NSEpositive neurons in SMC layer III on days 3, 7, and 14, and an increase in the number of NSE-positive neurons on day 30. The number of NSE-positive neurons in layer V of the SMC progressively decreased throughout the whole study period. The evolution of changes in the proportion of p38-positive material (synaptic terminal area) differed significantly between the layers of SMC. In the layers I and III, this parameter first decreased (days 1 and 3) and then increased (days 7, 14, and 30). In layer V of SMC, the activation of the protein expression was observed in the acute phase (days 1 and 3), then it decreased on days 7 and 14, and increased again on day 30. The changes found in the numerical density of neurons, glial cells and synaptic terminals were associated with dehydration and overhydration of SMC. We found strong to medium significant associations between the relative area of terminals and neuropil swelling and edema zones.Conclusion. After CCAL, layers I, III, and V of the SMC of white rats revealed destructive and compensatory changes in neurons, glial cells, and inter-neuronal communication structures. Taken together, all these changes indicate a significant layer-by-layer variability of the neural tissue response to CCAL. Layer III (secondary projection complex) of the SMC was affected to a greater extent. Reorganization of neuronal-glial and interneuronal interrelations occurred along with a prominent neuropil overhydration.

Development of the human perihypoglossal nuclei from mid-gestation to the perinatal period: A morphological study

IntroductionMorphological data on the development of the human perihypoglossal nuclei (PHN) are scarce. This study describes the morphology of the human PHN from mid-gestation to the perinatal period. Materials and methodsTen brains were collected from infants aged 21–43 postmenstrual weeks (PW). Serial sections were cut and stained using the Klüver–Barrera method. Morphometric parameters [volume, neuronal numerical density (Nv) and total number (Nt), and neuronal profile area (PA)] were analyzed from microscopic observations. ResultsFour PHN [nucleus of Roller (RO), interfascicular nucleus (IF), intercalated nucleus (IC), and prepositus nucleus (PR)] were identified at 21 PW. Medium-sized to large, oval, or polygonal neurons were concentrated in the ventral nuclei (RO and IF) and localized regions near the IC–PR transition of the dorsal nuclei (IC and PR). Small to large neurons of various shapes were scattered across the dorsal nuclei. The PR showed rostrocaudal differences in the neuronal cytoarchitecture. The volume of each nucleus increased between 21 and 43 PW, with a typical exponential increase for the dorsal nuclei. The Nv in each nucleus exponentially decreased, whereas the Nt was almost stable. The median PA linearly increased for every nucleus, and the increasing rates were greater for the ventral nuclei than those for the dorsal nuclei. ConclusionsThe dorsal and ventral PHN are identifiable at mid-gestation. The topographic relationships of the four nuclei are conserved until the perinatal period. The characteristic neuronal cytoarchitecture of each group is rapidly formed by 28–30 PW.

Some features of the brain of Wistar rats that developed in broods of various numbers

Objective: To study the morphofunctional features of the brain development of 14- and 30-day-old rats born in broods that differ significantly in numbers.Methods: 2 age groups of animals were studies – 14-day-old and 30-day-old rat pups, the offspring of intact rats, each group was divided into subgroups: 1) small broods (4-7 rat pups per brood) and 2) broods of average size (9-12 rats in a brood). The brains of animals of both subgroups were subjected to morphometric and histochemical studies. At the age of 28 days, rat pups from the second age group were tested in an elevated plus maze.Results: It was found that rat pups from small broods at the age of 14 and 30 days had signs of acceleration and differed in the outstripping rates of development of brain from animals from the group of broods of average size. Differences were manifested by a greater mass of the brain and hemisphere, a lower numerical density of neurons and a higher density of gliocytes, a large glioneural index, as well as the size of neurons, their nuclei and nucleoli in the cortex of the parietal lobe and the hippocampus. The behavior of pups from small broods and broods of average numbers at the age of 28 days in an elevated plus maze had significant intergroup differences.Conclusions: These findings indicate that differences in brood numbers affect important indicators of brain development.

Effect of Experimental Litters Reduction during the Neonatal and Suckling? Periods of Ontogeny on Some Parameters of Brain Development in 30-Day-Old Rats.

We compared the effect of litter reduction on day 1 (series I) and day 14 after birth (series II) on the weight of the brain and right hemisphere and on the morphometric indicators of the development of the anteroparietal lobe in rats. Animals from both experimental series showed signs of acceleration (higher body weight and weights of the testes and ovaries). In series I, the weight of the brain and hemisphere and the thickness of the cortex surpassed the control values; the numerical density of neurons in layers II and V was lower and the numerical density of gliocytes was higher than in the control. The size of the neuronal nuclei of these layers as well as the size of perikaryons of layer V neurons also surpassed the control. These differences can be considered as evidence of advanced brain development in experimental animals. In contrast, gravimetric and morphometric parameters in series II did not differ significantly from the control values. Thus, the factors that determine accelerated development of the brain after reduction of litter size in the neonatal period produced no similar effect after litter reduction on day 14 after birth.

EVIDENCE OF APOPTOSIS IN PARVOCELLULAR NUCLEI OF HYPOTHALAMUS IN DIABETES MELLITUS

Diabetes mellitus (DM) causes great socio-economic damage, which is determined by medical expenses and expenditure on social security to patients due to invalidity and loss of labour capacity. Researchers are studying the role of hypothalamic neuropeptides and their involvement in the regulation of pancreatic islet function. In view of the above, the aim of our study was to establish the features of morphofunctional changes in the arcuate nucleus (AN) and ventromedial nucleus (VN) of the hypothalamus in streptozotocin-induced diabetes mellitus (SIDM).
 Histological, immunohistochemical, electron-microscopic, biochemical and statistical research methods were used.
 Polymorphic changes were noted in AN and VN at early stages of development of SIDM (on the 14th day). In AN, the area of neurons and their nuclei became larger, the numerical density of dark functionally more active neurons increased, and dinuclear light neuroendocrine cells (NC) appeared. In light and dark NCs of AN, there was a significant increase in the bulk density of neurosecretory granules – by 2-4 times compared with the control, in VN – by 1.2-2 times.
 Such morphofunctional changes in parvocellular nuclei of the hypothalamus and the increase in the bulk density of neurosecretory granules in their NCs indicate boosted synthesis of neurohormones which directly affect the adenohypophysis and improving functional activity of NCs in AN and VN.
 On the 70th day of SIDM in AN and VN of the hypothalamus, there was a decrease in the numerical density of neurons due to light NC and increase in the numerical density of vacuolated, dark pycnomorphic and apoptotic neurons. The apoptotic index in the studied nuclei of the hypothalamus increased by 2-4 times compared with the control. The area of the profile field of NC increased and the area of nuclei decreased, which led to the reduced nuclear-cytoplasmic index and indicated a decrease in their functional activity and was confirmed by a decrease in the bulk density of neurosecretory granules in NC by 1.9-2.1 times in AN and by 2.7-4.7 times in VN. At the ultrastructural level, pronounced destructive processes such as vacuolar dystrophy, development of satelliteosis and neuronophagia were observed in light NCs.
 Thus, prolonged hyperglycemia in SIDM in parvocellular nuclei of the hypothalamus causes neuronal death to a lesser extent due to apoptosis, and to a greater extentdue due to hydropic dystrophy and colliquative necrosis, especially in the long term of the experiment (on the 70th day), and leads to the development of diabetic neuroendocrinopathy.

Development of the human hypoglossal nucleus from mid-gestation to the perinatal period: A morphological study

IntroductionThe human hypoglossal nucleus (nXII) was morphologically examined from mid-gestation to the perinatal period. Materials/methodsSerial brain sections from 6 preterm and 4 perinatal infants aged 21–43 postmenstrual weeks (PW) were stained with the Klüver–Barrera method. Following microscopic observation, morphometric parameters (volume, neuronal number, and neuronal profile area [PA]) were analysed. ResultsTwo types of neurons, motor and non-motor neurons, were observed at 21 PW. The motor neurons were distributed into clusters, which were not completely separated. The non-motor neurons were dispersed among the motor neurons. Myelination of the hypoglossal nerve roots was noted at 21 PW, when degenerated neurons were sporadically encountered. To a lesser extent, they were seen until 35 PW. The nXII volume increased exponentially with age. Conversely, the neuronal numerical density decreased exponentially, while the total number remained relatively stable. The neuronal PA increased gradually, with a greater rate of increase measured in the caudal part. ConclusionsIn the human nXII, motor and non-motor neurons are distinguishable from mid-gestation. Then, while the nXII expands exponentially in volume, the two types of neurons change in number and PA almost in parallel during the second half of gestation. Natural neuronal death may also occur.

Development of the human accessory olivary nuclei: A morphometric and computerized 3D-reconstruction study

IntroductionThis study described the prenatal development of the accessory olivary nuclei (AO) in humans. Materials/methodsSerial brain sections from ten pre- and full term infants aged 21–43 postmenstrual weeks (PW) were stained using the Klüver–Barrera method. A computerized 3D-reconstruction technique and morphometry were adopted for the study. ResultsThe medial AO (MAO) and dorsal AO (DAO) were identified at 21 PW. The dorsal cap was clearly differentiated from the main body (MB) of the MAO in neuronal cytoarchitecture. Pyknotic neurons were diffusely observed in the AO at 21 PW and were most concentrated in the MB. These neurons became infrequent from 28 PW onward. Neuronal nests existed in clusters between the AO and the medial lemniscus at 21 PW, which reduced progressively in size and number with age. The 3D-reconstructions showed that the AO are separated into caudal and rostral parts, and that this separation is achieved by mid-gestation in the DAO. Nuclear volume increased exponentially with age in the AO, although the rate of increase was half that of the principal nucleus (PO). Neuronal numerical density decreased rapidly 21–28 PW. The total neuronal number showed a weak correlation with age. The mean neuronal profile area increased linearly with age. ConclusionThe human AO are separated into caudal and rostral parts in the fetal period. The nuclear volume and neuronal profile areas increase with age, although the rate of this increase is lower than in the PO. Natural neuronal death may occur at mid-gestation in the AO.

Glial Cell Architecture Dynamics in Dentate Gyrus and CA4 Area of Wistar Rat Hippocampus Following 20-minute Occlusion of Common Carotid Arteries

Aim. To study the distribution and spatial organization of dentate gyrus (DG) astrocytes and CA4 area of hippocampus of Wistar rats following 20-minute occlusion of common carotid arteries (OCCA) compared to sham-operated control animals.Material and methods. Histological (Nissl staining with hematoxylin and eosin), immunohistochemical (GFAP, MAP-2) and morphometric methods were used. Astrocytes and neurons in control (sham-operated animals, n = 5) group, after 6 hours (n=5), 1 days (n=5), 3 days (n=5), 7 days (n=5), 14 days (n=5) and 30 days (n=5) after 20-minute OCCA were studied on thin (4 µm) serial frontal sections of the hippocampus. Fractal analysis (ImageJ 1.52; fraclac 2.5 plugin) was used to obtain additional quantitative information on the spatial organization of astrocyte networks. Statistical hypotheses were tested using nonparametric criteria.Results. 30 days after the 20-minute OCCA, only 5.3% of CA4 neurons were irreversibly destroyed and the total numerical density of DG granular cells remained at the control level. Hypertrophy and increased complexity of the spatial organization of astrocyte processes were observed 6 hours and 1 day after OCCA and persisted for 30 days. Astrogliosis was accompanied by an increased relative area of GFAP-positive material and fractal dimension and reduced lacunarity of the astrocyte network. The latter was especially evident in 1, 14 and 30 days after the OCCA.Conclusion. After the 20-minute OCCA, the density of GFAP-positive material increased, the fibroarchitecture reorganized and gained more complexity due to the branching of astrocyte processes. At the same time, the total numerical density of neurons changed only slightly. All this indicated the probable role of astrocytes in post-ischemic activation of natural neuroprotection mechanisms.

Neuroprotective effects of lovastatin in the pilocarpine rat model of epilepsy according to the expression of neurotrophic factors.

Studies have suggested that neurotrophic factors (NTFs) are involved in the status epilepticus development. This indicates their essential role in mediating acquired epileptic conditions. Therefore, modulating the expression of NTFs may inhibit seizure-induced cell loss in the epileptic lesions. In this study, we examined the anti-apoptotic, anti-necrotic and regulatory effects of lovastatin on the expression of NTFs in the pilocarpine rat model of temporal lobe epilepsy (TLE). A total of 32 male Wistar rats were divided into 4 groups (n = 8 per group): i) normal; ii) non-treated epileptic group [intraperitoneal (i.p.) administration of 350-400mg/kg pilocarpine]; iii) treatment group (pilocarpine-treated rats treated followed by 5mg/kg lovastatin); and iv) vehicle epileptic rats treated with Carboxymethyl cellulose (CMC). Animals that had a behavioral score of 4-5 according to the Racine scale were selected for study participation. Three days after the first seizure, pilocarpine-treated rats received i.p. injections of lovastatin for 14days. The rats were killed and prepared for histopathologic analysis as well as real-time RT-PCR 17days after the first seizure. The results of this study showed increased mRNA expression of glial cell line-derived neurotrophic factor (GDNF) and Ciliary neurotrophic factor (CNTF) and decreased expressions of Brain-derived neurotrophic factor (BDNF), Neurotrophin-3 (NT-3), and Neurotrophin-4 (NT-4) mRNA in the epileptic rats treated with lovastatin. Histological analysis of neurodegeneration in the brain sections showed that the number of hippocampal apoptotic and necrotic cells significantly decreased in the treatment groups. Furthermore, numerical density of neurons per area was significantly higher in the treated groups compared with the untreated groups. Collectively, the results of this study have shown that lovastatin could attenuate seizure-induced expression of neurotrophic factors and consequently reduce hippocampal cell death in the pilocarpine rat model of TLE.

Immediate and Delayed Effects of Food Restriction on Some Parameters of Brain Development in Rats.

The effects of 15-day restriction diet (from 1 to 1.5 months of age) on some parameters of brain development were studied in rats. The immediate and delayed (15 days after transfer to normal ration) effects were evaluated. The immediate effects included a significant decrease of the absolute weights of the brain and hemispheres. The relative weight of the brain was significantly higher. The thickness of the cortex of the parietal lobe proper and its layer I decreased. The absolute weights of the brain and hemispheres were less than in the control 15 days after the rats were transferred to ad libitum feeding, while the relative weight of the brain was higher than in controls. The thickness of the parietal and anterior parietal cortex and the numerical density of neurons in layers II and V did not differ from the control. In the neurons of layers II and V of the anterior parietal and parietal lobe proper the nuclei were larger, while the nucleoli were enlarged in the neurons of these locations and the hippocampus, the shifts being significant in the anterior parietal layer V. The concentrations of RNA in the parietal, anterior parietal, and hippocampal lobe neurons in different groups were similar directly and 15 days after the diet. Changes in the gravimetric and morphometric parameters of the brain were paralleled by the development of oxidative stress.

PLEIOTROPIC ENZYMES OF APOPTOSIS AND SYNAPTIC PLASTICITY IN ALBINO RAT HIPPOCAMPUS AFTER OCCLUSION OF COMMON CAROTID ARTERIES

Aim: the aim of the study was to investigate the pleiotropic properties of the apoptotic enzyme caspase-3 and its associations with the synaptic plasticity of the hippocampus of albino rats in healthy animals and in rats after 20-min occlusion of the common carotid arteries.Material and Methods. Total numerical density of neurons, ultrastructure of synapses, and area of immunohistochemically positive hippocampal synaptic terminals of CA1 stratum radiatum and stratum lucidum CA3 were studied by the methods of optical microscopy (hematoxylin and eosin stain), electron microscopy (uranyl acetate and lead citrate as contrast agents), immunohistochemistry (MAP2, synaptophysin, caspase-3, p53, and bcl-2), and morphometry in the brains of intact rats (n=5) and in animals after acute ischemia at day 1 (n=5), 3 (n=5), 7 (n=5), 14 (n=5), and 30 (n=25).Results and Discussion. The study showed that 33.0% of pyramidal neurons in CA1 region and 17.4% of those in CA3 region underwent irreversible damage within 30 days of the post-ischemic period. Among the irreversibly damaged neurons, the cells with signs of coagulative-ischemic necrosis prevailed. In animals subject to ischemia, the relative area of synaptophysin-positive material initially decreased (at day 1) and then recovered (at days 3, 7). We found that caspase-3 colocalized with synaptophysin, which was especially evident in the giant synapses of the stratum lucidum of the hippocampal CA3 region. In the neurosomes of the hippocampal pyramidal cells, caspase-3 was not detected. However, this enzyme was found in the terminals of the axo-dendritic, axo-spine, and axo-somatic synapses. In the course of th e post-ischemic period, the most pronounced changes in the expression of caspase-3 were observed in the stratum radiatum of the CA1 field. Apoptosis regulatory proteins (p53, bcl-2) were detected in the individual neurons. In this regard, caspase-3 should be viewed in the context of its pleiotropy and involvement in the adaptation and recovery processes due to post-ischemic activation of neuroplasticity at the level of axons and synapses.Conclusion. After acute ischemia caused by 20-min occlusion of the common carotid arteries, the activation of caspase-3 contributes to ischemic preconditioning and neuroprotection.

Neuroprotective effect of lovastatin through down-regulation of pro-apoptotic Mst1 gene expression in rat model pilocarpine epilepsy

ABSTRACTObjective: Statins as inhibitors of HMG-CoA reductase have been recently recognized as anti-inflammatory and neuroprotective drugs. In this paper, we studied anti-apoptotic and regulatory effects of lovastatin using Pilocarpine rat model through downregulation of Mst1 (Mammalian sterile 20-like kinase 1) as a novel pro-apoptotic gene.Methods: The rats were divided into four groups: non-treated epileptic rats, lovastatin treated, and two vehicle groups. Racine scale was used for behavioral assessment and animals with a score of 4–5 were selected for the study. After 3 days, epileptic rats received intraperitoneal injections of lovastatin, followed by treating for 14 days. Next, they were sacrificed (28 post-first seizure) and prepared for histopathological analysis and Real-time RT-PCR.Results: The results showed that lovastatin protects Pilocarpine-induced cell death via a regulatory effect on pro-apoptotic and anti-apoptotic gene expression. The real-time PCR results showed that in the epileptic lovastatin treated group, the expression level of Mst1 significantly decreased while Nrf2 and Bcl-2 genes increased. Furthermore, histological analysis of neurodegeneration in the brain sections showed that the number of hippocampal apoptotic cells significantly decreased in the treatment groups. The results showed that the numerical density of neurons per area was significantly higher in the treated than the untreated group.Conclusion: Overall, the results of this study showed that lovastatin attenuates hippocampal cell death in Pilocarpine-induced status epilepticus rat model through downregulation of the pro-apoptotic Mst1 gene.Abbreviations: Mst1: Mammalian sterile 20-like kinase 1; Nrf2: nuclear factor erythroid 2–related factor 2; Bcl-2: B-cell lymphoma 2; HMG-CoA: 3-hydroxy-3-methylglutaryl-coenzyme A; RT-PCR: reverse transcription-polymerase chain reaction; TLE: Temporal Lobe Epilepsy; SE: status epilepticus.

Features of the White Rats’ Neocortex, Archicortex and Amygdala Changes After Acute Ischemia

The aim of the study is to evaluate neurons and synapses of the sensorimotor cortex, hippocampus and amygdala of the brain of white rats in the normal state and after 20-minute occlusion of the common carotid arteries. Material and methods. Light microscopy, immunohistochemistry (synaptophysin or P38) and morphometry were used to study the total numerical density of neurons and the area of sections of synaptic terminals of the brain in normal (n=5) and 1, 3, 7, 14, 30 days (n=25) after acute ischemia. Results. Within 30 days of the postischemic period, of the sensorimotor cortex in the layer III irreversible destruction have been 21.5% and in layer V of 19.0% of neurons in field CA 1 of the hippocampus - 33.0%, CA 3 - 17,4%, СА 4 - 5.3% of neurons in the amygdala - the 15.1% average and 6.2% of the large neurons. The decrease in the relative area of P38-positive material of mainly axospines and axodendritic synapses changed the ratio of functioning synapses on the bodies and dendrites of neurons in favor of axosomatic, which are mainly inhibitory. Conclusion. All of this could be the basis of recovery and of dysfunction of interneuronal relationships, predisposing to the development of postischemic encephalopathy.

An improved three-vessel occlusion model of global cerebral ischemia in rats

We developed an improved three-vessel occlusion model of global cerebral ischemia in rats. This method consists in cessation of cerebral blood flow by accessing a. carotis communis sinistra through the ventral surface of the neck as well as tr. brachiocephalicus and a. subclavia sinistra through the first intercostal space, bypassing the pleural cavity and excluding pneumothorax. After the occlusion of the vessels that resulted in interruption of their blood flow, according to laser-Doppler flowmetry, there was a sharp decline in local cerebral blood flow in the visual cortex to 4±1% of the initial level. After restoring the level of local cerebral blood flow at the 5th minute, 10th minute, 20th minute and 24th hour of reperfusion, the levels of local cerebral blood flow were 51±7%, 41±5%, 35±8% and 54±9% of the initial level, respectively. Histo-quantitative analysis of changes in neurons of the hippocampus of rats showed that after ischemic injury, the numerical density of neurons in hippocampal zone CA1 in the observed 1mm2 region decreased by 29%, 22%, and 35%, respectively, compared to sham-operated animals (p<0.05). By the first day after global cerebral ischemia, the experimental group had shown a mean neurological deficit score equal to 7.5±1.0 and 7.9±0.7 points, followed by a decrease up to score 6.5±1.1 and 5.9±0.7 on the third day, 4.6±0.8 and 4.7±0.5 on the fifth day (on chloral hydrate and propofol anesthesia correspondently).

The Effects of Acoustic White Noise on the Rat Central Auditory System During the Fetal and Critical Neonatal Periods: A Stereological Study.

Aim:To evaluate the effects of long-term, moderate level noise exposure during crucial periods of rat infants on stereological parameters of medial geniculate body (MGB) and auditory cortex.Materials and Methods:Twenty-four male offspring of 12 pregnant rats were divided into four groups: fetal-to-critical period group, which were exposed to noise from the last 10 days of fetal life till postnatal day (PND) 29; fetal period group that exposed to noise during the last 10 days of fetal life; critical period group, exposed to noise from PND 15 till PND 29, and control group. White noise at 90 dB for 2 h per day was used.Statistical Analysis Used:Variance for variables was performed using Proc GLM followed by mean comparison by Duncan’s multiple range test.Results:Numerical density of neurons in MGB of fetal-to-critical period group was lower than control group. Similar results were seen in numerical density of neurons in layers IV and VI of auditory cortex. Furthermore, no significant difference was observed in the volume of auditory cortex among groups, and only MGB volume in fetal-to-critical period group was higher than other groups. Estimated total number of neurons in MGB was not significantly different among groups.Conclusion:It seems necessary to prevent long-term moderate level noise exposure during fetal-to-critical neonatal period.

Natural Defense Mechanisms of the Human Brain against Chronic Ischemia

Objective: to study the structural bases of natural defense mechanisms of the human brain against chronic ischemia. Materials and methods. To accomplish this, histological, immunohistochemical (NSE, calbindin, NPY, p38) and morphometric examinations of intraoperative biopsy specimens were performed to determine the reorganization of excitatory and inhibitory neurons in the ischemic penumbra of the temporal cerebral cortex (CC). Morphometric analysis was made using the specially developed algorithms to verify neurons and their elements in the ImageJ 1.46 program. Results . The reduction in the total numerical density of neurons and synapses in chronic ischemia was ascertained to be accompanied by the compensatorily enhanced expression of NSE, calbindin, p38, and NPY in the remaining CC neurons. There were signs of hypertrophy of inhibitory CC interneurons and growth of their processes. In consequence, the impact of inhibitory CC interneurons on excitatory neurons was likely to enhance. Conclusion . In chronic ischemia, the human brain is anticipated to respond to damage to some cells via compensatory excitatory and inhibitory neuronal reorganization directed towards its natural defense against excitatory damage and towards better conditions for compensatory recovery of the structure and function of CC.