Effect of environmental enrichment on behavioral and morphological outcomes following neonatal hypoxia-ischemia in rodent models: A systematic review and meta-analysis.

Neonatal hypoxia-ischemia (HI) is a major cause of mortality and morbidity in newborns and, despite recent advances in neonatal intensive care, there is no definitive treatment for this pathology. Once preclinical studies have shown that environmental enrichment (EE) seems to be a promising therapy for children with HI, the present study conducts a systematic review and meta-analysis of articles with EE in HI rodent models focusing on neurodevelopmental reflexes, motor and cognitive function as well as brain damage. The protocol was registered a priori at PROSPERO. The search was conducted in PubMed, Embase and PsycINFO databases, resulting in the inclusion of 22 articles. Interestingly, EE showed a beneficial impact on neurodevelopmental reflexes (SMD= -0.73, CI= [-0.98; -0.47], p< 0.001, I2= 0.0%), motor function (SMD= -0.55, CI= [-0.81; -0.28], p< 0.001, I2= 62.6%), cognitive function (SMD= -0.93, CI= [-1.14; -0.72], p< 0.001, I2= 27.8%) and brain damage (SMD= -0.80, CI= [-1.03; -0.58], p< 0.001, I2= 10.7%). The main factors that potentiate EE positive effects were enhanced study quality, earlier age at injury as well as earlier start and longer duration of EE exposure. Overall, EE was able to counteract the behavioral and histological damage induced by the lesion, being a promising therapeutic strategy for HI.

Arundic Acid (ONO-2506) Attenuates Neuroinflammation and Prevents Motor Impairment in Rats with Intracerebral Hemorrhage.

Intracerebral hemorrhage (ICH) is a severe stroke subtype caused by the rupture of blood vessels within the brain. Increased levels of S100B protein may contribute to neuroinflammation after ICH through activation of astrocytes and resident microglia, with the consequent production of proinflammatory cytokines and reactive oxygen species (ROS). Inhibition of astrocytic synthesis of S100B by arundic acid (AA) has shown beneficial effects in experimental central nervous system disorders. In present study, we administered AA in a collagenase-induced ICH rodent model in order to evaluate its effects on neurological deficits, S100B levels, astrocytic activation, inflammatory, and oxidative parameters. Rats underwent stereotactic surgery for injection of collagenase in the left striatum and AA (2 µg/µl; weight × 0.005) or vehicle in the left lateral ventricle. Neurological deficits were evaluated by the Ladder rung walking and Grip strength tests. Striatal S100B, astrogliosis, and microglial activation were assessed by immunofluorescence analysis. Striatal levels of interleukin 1ß (IL-1ß) and tumor necrosis factor α (TNF-α) were measured by ELISA, and the ROS production was analyzed by dichlorofluorescein (DCF) oxidation. AA treatment prevented motor dysfunction, reduced S100B levels, astrogliosis, and microglial activation in the damaged striatum, thus decreasing the release of proinflammatory cytokines IL-1ß and TNF-α, as well as ROS production. Taken together, present results suggest that AA could be a pharmacological tool to prevent the harmful effects of increased S100B, attenuating neuroinflammation and secondary brain damage after ICH.

Pregnancy swimming prevents early brain mitochondrial dysfunction and causes sex-related long-term neuroprotection following neonatal hypoxia-ischemia in rats.

Neonatal hypoxia-ischemia (HI) is a major cause of cognitive impairments in infants. Antenatal strategies improving the intrauterine environment can have high impact decreasing pregnancy-derived intercurrences. Physical exercise alters the mother-fetus unity and has been shown to prevent the energetic challenge imposed by HI. This study aimed to reveal neuroprotective mechanisms afforded by pregnancy swimming on early metabolic failure and late cognitive damage, considering animals' sex as a variable. Pregnant Wistar rats were submitted to daily swimming exercise (20' in a tank filled with 32 °C water) during pregnancy. Neonatal HI was performed in male and female pups at postnatal day 7. Electron chain transport, mitochondrial mass and function and ROS formation were assessed in the right brain hemisphere 24 h after HI. From PND45, reference and working spatial memory were tested in the Morris water maze. MicroPET-FDG images were acquired 24 h after injury (PND8) and at PND60, following behavioral analysis. HI induced early energetic failure, decreased enzymatic activity in electron transport chain, increased production of ROS in cortex and hippocampus as well as caused brain glucose metabolism dysfunction and late cognitive impairments. Maternal swimming was able to prevent mitochondrial dysfunction and to improve spatial memory. The intergenerational effects of swimming were sex-specific, since male rats were benefited most. In conclusion, maternal swimming was able to affect the mitochondrial response to HI in the offspring's brains, preserving its function and preventing cognitive damage in a sex-dependent manner, adding relevant information on maternal exercise neuroprotection and highlighting the importance of mitochondria as a therapeutic target for HI neuropathology.

Experimental cerebral palsy causes microstructural brain damage in areas associated to motor deficits but no spatial memory impairments in the developing rat.

INTRODUCTION: Cerebral palsy (CP) is the major cause of motor and cognitive impairments during childhood. CP can result from direct or indirect structural injury to the developing brain. In this study, we aimed to describe brain damage and behavioural alterations during early adult life in a CP model using the combination of maternal inflammation, perinatal anoxia and postnatal sensorimotor restriction. METHODS: Pregnant Wistar rats were injected intraperitoneally with 200 µg/kg LPS at embryonic days E18 and E19. Between 3 and 6 h after birth (postnatal day 0 - PND0), pups of both sexes were exposed to anoxia for 20 min. From postnatal day 2 to 21, hindlimbs of animals were immobilized for 16 h daily during their active phase. From PND40, locomotor and cognitive tests were performed using Rota-Rod, Ladder Walking and Morris water Maze. Ex-vivo MRI Diffusion Tensor Imaging (DTI) and Neurite Orientation Dispersion and Density Imaging (NODDI) were used to assess macro and microstructural damage and brain volume alterations induced by the model. Myelination and expression of neuronal, astroglial and microglial markers, as well as apoptotic cell death were evaluated by immunofluorescence. RESULTS: CP animals showed decreased body weight, deficits in gross (rota-rod) and fine (ladder walking) motor tasks compared to Controls. No cognitive impairments were observed. Ex-vivo MRI showed decreased brain volumes and impaired microstructure in the cingulate gyrus and sensory cortex in CP brains. Histological analysis showed increased cell death, astrocytic reactivity and decreased thickness of the corpus callosum and altered myelination in CP animals. Hindlimb primary motor cortex analysis showed increased apoptosis in CP animals. Despite the increase in NeuN and GFAP, no differences between groups were observed as well as no co-localization with the apoptotic marker. However, an increase in Iba-1+ microglia with co-localization to cleaved caspase 3 was observed. CONCLUSION: Our results suggest that experimental CP induces long-term brain microstructural alterations in myelinated structures, cell death in the hindlimb primary motor cortex and locomotor impairments. Such new evidence of brain damage could help to better understand CP pathophysiological mechanisms and guide further research for neuroprotective and neurorehabilitative strategies for CP patients.

Arundic Acid (ONO-2506), an Inhibitor of S100B Protein Synthesis, Prevents Neurological Deficits and Brain Tissue Damage Following Intracerebral Hemorrhage in Male Wistar Rats.

Stroke is one of the leading causes of mortality and neurological morbidity. Intracerebral hemorrhage (ICH) has the poorest prognosis among all stroke subtypes and no treatment has been effective in improving outcomes. Following ICH, the observed high levels of S100B protein have been associated with worsening of injury and neurological deficits. Arundic acid (AA) exerts neuroprotective effects through inhibition of astrocytic synthesis of S100B in some models of experimental brain injury; however, it has not been studied in ICH. The aim of this study was to evaluate the effects of intracerebroventricular (ICV) administration of AA in male Wistar rats submitted to ICH model assessing the following variables: reactive astrogliosis, S100B levels, antioxidant defenses, cell death, lesion extension and neurological function. Firstly, AA was injected at different doses (0.02, 0.2, 2 and 20 µg/µl) in the left lateral ventricle in order to observe which dose would decrease GFAP and S100B striatal levels in non-injured rats. Following determination of the effective dose, ICH damage was induced by IV-S collagenase intrastrial injection and 2 µg/µl AA was injected through ICV route immediately before injury. AA treatment prevented ICH-induced neurological deficits and tissue damage, inhibited excessive astrocytic activation and cellular apoptosis, reduced peripheral and central S100B levels (in striatum, serum and cerebrospinal fluid), improved neuronal survival and enhanced the antioxidant defences after injury. Altogether, these results suggest that S100B is a viable target for treating ICH and highlight AA as an interesting strategy for improving neurological outcome after experimental brain hemorrhage.

Differential glucose and beta-hydroxybutyrate metabolism confers an intrinsic neuroprotection to the immature brain in a rat model of neonatal hypoxia ischemia.

Neonatal hypoxia ischemia (HI) is the main cause of newborn mortality and morbidity. Preclinical studies have shown that the immature rat brain is more resilient to HI injury, suggesting innate mechanisms of neuroprotection. During neonatal period brain metabolism experience changes that might greatly affect the outcome of HI injury. Therefore, the aim of the present study was to investigate how changes in brain metabolism interfere with HI outcome in different stages of CNS development. For this purpose, animals were divided into 6 groups: HIP3, HIP7 and HIP11 (HI performed at postnatal days 3, 7 and 11, respectively), and their respective shams. In vivo [18F]FDG micro positron emission tomography (microPET) imaging was performed 24 and 72 h after HI, as well as ex-vivo assessments of glucose and beta-hydroxybutyrate (BHB) oxidation. At adulthood behavioral tests and histology were performed. Behavioral and histological analysis showed greater impairments in HIP11 animals, while HIP3 rats were not affected. Changes in [18F]FDG metabolism were found only in the lesion area of HIP11, where a substantial hypometabolism was detected. Furthermore, [18F]FDG hypometabolism predicted impaired cognition and worst histological outcomes at adulthood. Finally, substrate oxidation assessments showed that glucose oxidation remained unaltered and higher level of BHB oxidation found in P3 animals, suggesting a more resilient metabolism. Overall, present results show [18F]FDG microPET predicts long-term injury outcome and suggests that higher BHB utilization is one of the mechanisms that confer the intrinsic neuroprotection to the immature brain and should be explored as a therapeutic target for treatment of HI.

Previous adaptation triggers distinct molecular pathways and modulates early and long-term neuroprotective effects of pregnancy swimming preventing neonatal hypoxia-ischemia damage in rats.

Neonatal hypoxia-ischemia (HI) is one of the main causes of neurological damage in newborns. Pregnancy swimming (PS) alters brain maturation and has neuroprotective effects following HI; however, variables such as timing play a decisive role in its effects. Prior to mating, we tested if adaptation of female rats to a tank filled with water at 32 °C for 7 days before mating, modulates PS benefits. After mating, rats swam 20 min/day or remained in standard cages. Seven-day-old pups were subjected to HI (right common carotid artery occlusion followed by FiO2 8% for 60 min). Animals were divided into 8 experimental groups, adaptation, swimming and injury. Astrocytic reactivity, apoptosis-related proteins, neurotrophins and cell survival markers expression were assessed in the hippocampus 24 h after HI. From PND45, animals performed behavioral tests followed by histological assessment. Three-way ANOVA showed a significant increase in astrogliosis only in non-adapted HI animals. Swimming decreased apoptotic cell death despite adaptation period in both exercised groups. Cylinder evidenced HI impairments; no effect of swimming or adaptation period were observed. In the open field, only HI animals whose mothers had been adapted had increased locomotion; moreover, swimming reversed HI damage. Hemisphere and hippocampus were preserved only in the HI group whose mothers swam before mating, suggesting a preconditioning effect mediated by the adaptation. In summary, adaptation period plays a major role in the mechanisms involving neuroprotection afforded by PS and needs to be further explored in future studies involving damage to the neonatal brain.

Chronic mild hyperhomocysteinemia induces anxiety-like symptoms, aversive memory deficits and hippocampus atrophy in adult rats: New insights into physiopathological mechanisms.

In the last decade, increased homocysteine levels have been implicated as a risk factor for neurodegenerative and psychiatric disorders. We have developed an experimental model of chronic mild hyperhomocysteinemia (HHcy) in order to observe metabolic impairments in the brain of adult rodents. Besides its known effects on brain metabolism, the present study sought to investigate whether chronic mild HHcy could induce learning/memory impairments associated with biochemical and histological damage to the hippocampus. Adult male Wistar rats received daily subcutaneous injections of homocysteine (0.03 µmol/g of body weight) twice a day, from the 30th to the 60th day of life or saline solution (Controls). After injections, anxiety-like and memory tests were performed. Following behavioral analyses, brains were sliced and hippocampal volumes assessed and homogenized for redox state assessment, antioxidant activity, mitochondrial functioning (chain respiratory enzymes and ATP levels) and DNA damage analyses. Behavioral analyses showed that chronic mild HHcy may induce anxiety-like behavior and impair long-term aversive memory (24 h) that was evaluated by inhibitory avoidance task. Mild HHcy decreased locomotor and/or exploratory activities in elevated plus maze test and caused hippocampal atrophy. Decrease in cytochrome c oxidase, DNA damage and redox state changes were also observed in hippocampus of adult rats subjected to mild HHcy. Our findings show that chronic mild HHcy alters biochemical and histological parameters in the hippocampus, leading to behavioral impairments. These findings might be considered in future studies aiming to search for alternative strategies for treating the behavioral impairments in patients with mild elevations in homocysteine levels.

Tissue Injury and Astrocytic Reaction, But Not Cognitive Deficits, Are Dependent on Hypoxia Duration in Very Immature Rats Undergoing Neonatal Hypoxia-Ischemia.

Preterm birth and hypoxia-ischemia (HI) are major causes of neonatal death and neurological disabilities in newborns. The widely used preclinical HI model combines carotid occlusion with hypoxia exposure; however, the relationship between different hypoxia exposure periods with brain tissue loss, astrocyte reactivity and behavioral impairments following HI is lacking. Present study evaluated HI-induced behavioral and morphological consequences in rats exposed to different periods of hypoxia at postnatal day 3. Wistar rats of both sexes were assigned into four groups: control group, HI-120 min, HI-180 min and HI-210 min. Neurodevelopmental reflexes, exploratory abilities and cognitive function were assessed. At adulthood, tissue damage and reactive astrogliosis were measured. Animals exposed to HI-180 and HI-210 min had delayed neurodevelopmental reflexes compared to control group. Histological assessment showed tissue loss that was restricted to the ipsilateral hemisphere in lower periods of hypoxia exposure (120 and 180 min) but affected both hemispheres when 210 min was used. Reactive astrogliosis was increased only after 210 min of hypoxia. Interestingly, cognitive deficits were induced regardless the duration of hypoxia and there were correlations between behavioral parameters and cortex, hippocampus and corpus callosum volumes. These results show the duration of hypoxia has a close relationship with astrocytic response and tissue damage progression. Furthermore, the long-lasting cognitive memory deficit and its association with brain structures beyond the hippocampus suggests that complex anatomical changes should be involved in functional alterations taking place as hypoxia duration is increased, even when the cognitive impairment limit is achieved.

Arundic acid administration protects astrocytes, recovers histological damage and memory deficits induced by neonatal hypoxia ischemia in rats.

INTRODUCTION: Perinatal hypoxia-ischemia (HI) is one of the main causes of mortality and chronic neurological morbidity in infants and children. Astrocytes play a key role in HI progression, becoming reactive in response to the injury, releasing S100 calcium binding protein B (S100B). Since S100B inhibition seems to have neuroprotective effects on central nervous system injury models, here we evaluated the neuroprotective effects of an S100B inhibitor, arundic acid (AA) in a HI model. METHODS: On the 7th postnatal day, animals were submitted to the combination of common carotid artery occlusion and hypoxic atmosphere (8% O2) for 60 min. Three experiments were performed in order to: (1) define AA dose (0.1, 1 or 10 mg/kg, pre-hypoxia i.p. injection), (2) test if repeated AA administrations (10 mg/kg at 3 time points: Pre-hypoxia, 24 h and 48 h after HI) would improve the response and (3) investigate biochemical mechanisms involved in AA protection two days after HI. RESULTS: AA at a dose of 10 mg/kg applied before and after hypoxia, was the only treatment protocol that was able to improve HI-induced memory deficits, to reduce tissue damage, to promote astrocytic survival in the hippocampus and to reduced extracellular release of S100B in the cerebrospinal fluid. CONCLUSION: Overall, AA treatment showed beneficial effects on memory deficits, tissue damage, promoting astrocyte survival likely by reducing S100B release. Protection aided to astrocytes by AA treatment against HI lesion may lead to development of new therapeutic strategies that target these particular cells.

Enriched experience during pregnancy and lactation protects against motor impairments induced by neonatal hypoxia-ischemia.

Neonatal hypoxia-ischemia (HI) is responsible for movement disorders in preterm infants. Non-pharmacological strategies, such as environmental enrichment (EE) during adulthood, have shown positive effects on promoting sensorimotor recovery after HI. However, little is known about the effects of perinatal EE on sensorimotor function following HI. In present study we investigated the hypothesis that enriched experiences during pregnancy and lactation would reduce motor impairments caused by a model of neonatal HI in rats. At postnatal day (PND) 3, Wistar pups of both sexes were subject to the modified Rice-Vannucci model. Motor function was evaluated from PND 60 to PND 64. HI caused a reduction in the forepaws strength and worsening of movement quality in the right forepaw. These effects were attenuated in animals receiving prenatal or lactational EE, which showed better performance when compared to the control group. Moreover, enriched experiences during lactation reversed HI-induced asymmetric use of the forepaws and the trend to increased paw errors in a walking test. Lower scores were found in the contralateral forepaw placement in HI animals, except when EE was provided at both stages of neurodevelopment. These results indicate that enriched experiences reduce motor impairments, i.e, measured in force, asymmetry and coordination domains, and that EE during lactation is more effective in promoting post-injury recovery. These data support that early therapeutic interventions might enhance functional reorganization at a period of high brain plasticity and that enriched-like experience might be encouraged in pediatric rehabilitation programs, in order to reduce long-term movement disorders after neonatal brain insults.

Preventive and therapeutic effects of environmental enrichment in Wistar rats submitted to neonatal hypoxia-ischemia.

Environmental enrichment (EE) at early stages of neurodevelopment attenuates HI-induced behavioral, histological and cellular damage. However, the effects of EE exposure during gestational or early postnatal period and the possible influence of sexual dimorphism on EE protection are not fully understood. Present study evaluated the effects of pre-natal and postnatal EE, as well as their combination, in male and female rats submitted to neonatal HI at postnatal day (PND) 3. Wistar rats were housed in EE or in standard condition (SC) during all pregnancy. At PND1, the litters were randomly allocated to the same prenatal environment during lactation (SC + SC or EE + EE) or housed in a new environment until weaning (SC + EE or EE + SC). Behavioral tasks were performed from PND 60-75. Then, animals were euthanized for biochemical and histological analysis. Prenatal and early postnatal EE alone improved performance of HI males in the Water Maze spatial memory task, while HI females were most benefited from early postnatal stimulation. Moreover, EE attenuated HI-induced lower anxiety-like behavior in rats of both sexes and decreased hyperlocomotion in HI females. Hippocampus tissue preservation and higher VEGF and TrkB levels were observed in all HI groups exposed to EE. Interestingly, HI males exposed to prenatal or postnatal EE alone exhibited higher GFAP levels and additional tissue preservation. Therefore, both prenatal and early postnatal environmental enrichment cause attenuation of HI-induced impairments, revealing their preventive and therapeutic actions, possibly due to VEGF and astrocyte activity; some of these effects are sex-specific.

Locomotor Training Promotes Time-dependent Functional Recovery after Experimental Spinal Cord Contusion.

Locomotor training (LT) has been exhaustively investigated as a treatment for the spinal cord injury (SCI), however the literature reports both positive and negative effects over the functional recovery. The initiation period of LT following SCI is one of the major variables that needs attention. To investigate the better period, three different starting times were investigated after SCI in rats. Methods: Wistar rats were randomly divided into groups: control, SCI (rats with spinal cord contusion), and SCI groups exposed to LT starting 7, 14 or 28 days after the injury (SCI-T7, SCI-T14 and SCI-T28). LT was performed on a treadmill, five days a week, 20 minutes per day, for ten weeks. Basso, Breattie and Bresnahan (BBB) scale and Horizontal Ladder walking test were used to evaluate the motor function; at the end, morphological and biochemical analyses of the spinal cords, tibialis anterior and soleus muscles were performed. Results: SCI-T14 and SCI-T28 groups had an improvement in both behavioral tests, while SCI-T7 presented a worsening in the functional performance. Late training groups preserved motoneurons in the spinal cord, showed larger muscle fiber areas and higher BDNF expression in tibialis anterior muscle. SCI-T7 group had higher lesion volume after LT in comparison with the SCI group. Late onset of LT promoted an increment of the hindlimb function, while early onset of training worsened the functional recovery of the SCI animals. These results demonstrate a critical LT starting time after the injury, contributing to define the best therapeutic window for rehabilitation.

Pregnancy as a valuable period for preventing hypoxia-ischemia brain damage.

Neonatal brain Hypoxia-Ischemia (HI) is one of the major causes of infant mortality and lifelong neurological disabilities. The knowledge about the physiopathological mechanisms involved in HI lesion have increased in recent years, however these findings have not been translated into clinical practice. Current therapeutic approaches remain limited; hypothermia, used only in term or near-term infants, is the golden standard. Epidemiological evidence shows a link between adverse prenatal conditions and increased risk for diseases, health problems, and psychological outcomes later in life, what makes pregnancy a relevant period for preventing future brain injury. Here, we review experimental literature regarding preventive interventions used during pregnancy, i.e., previous to the HI injury, encompassing pharmacological, nutritional and/or behavioral strategies. Literature review used PubMed database. A total of forty one studies reported protective properties of maternal treatments preventing perinatal hypoxia-ischemia injury in rodents. Pharmacological agents and dietary supplementation showed mainly anti-excitotoxicity, anti-oxidant or anti-apoptotic properties. Interestingly, maternal preconditioning, physical exercise and environmental enrichment seem to engage the same referred mechanisms in order to protect neonatal brain against injury. This construct must be challenged by further studies to clearly define the main mechanisms responsible for neuroprotection to be explored in experimental context, as well as to test their potential in clinical settings.

Prenatal and Early Postnatal Environmental Enrichment Reduce Acute Cell Death and Prevent Neurodevelopment and Memory Impairments in Rats Submitted to Neonatal Hypoxia Ischemia.

Environmental enrichment (EE) is an experimental strategy to attenuate the negative effects of different neurological conditions including neonatal hypoxia ischemia encephalopathy (HIE). The aim of the present study was to investigate the influence of prenatal and early postnatal EE in animals submitted to neonatal HIE model at postnatal day (PND) 3. Wistar rats were housed in EE or standard conditions (SC) during pregnancy and lactation periods. Pups of both sexes were assigned to one of four experimental groups, considering the early environmental conditions and the injury: SC-Sham, SC-HIE, EE-sham, and EE-HIE. The offspring were euthanized at two different time points: 48 h after HIE for biochemical analyses or at PND 67 for histological analyses. Behavioral tests were performed at PND 7, 14, 21, and 60. Offspring from EE mothers had better performance in neurodevelopmental and spatial memory tests when compared to the SC groups. HIE animals showed a reduction of IGF-1 and VEGF in the parietal cortex, but no differences in BDNF and TrkB levels were found. EE-HIE animals showed reduction in cell death, lower astrocyte reactivity, and an increase in AKTp levels in the hippocampus and parietal cortex. In addition, the EE was also able to prevent the hippocampus tissue loss. Altogether, present findings point to the protective potential of the prenatal and early postnatal EE in attenuating molecular and histological damage, as well as the neurodevelopmental impairments and the cognitive deficit, caused by HIE insult at PND 3.

Glial-associated changes in the cerebral cortex after collagenase-induced intracerebral hemorrhage in the rat striatum.

Striatum and the cerebral cortex are regions susceptible to secondary injury after intracerebral hemorrhage (ICH) and glial cells in tissue adjacent to the hematoma may modulate cellular vulnerability after brain damage. Nonetheless, while the glial- associated changes occurring in the cerebral cortex after ICH may be important in maximizing brain recovery, they are not fully understood. The aim of this study was to evaluate the temporal profile of glial-associated changes in the cerebral cortex after ICH. First, the motor consequences of ICH and its relation to the lesion volume were analyzed. Secondly, glial cell proportion (GFAP+ and S100B+ astrocytes, CD11+ microglia) in the ipsilesional sensorimotor cortex and striatum, using flow cytometry were evaluated. ELISA was used to measure GFAP and S100B content in these structures as well as S100B levels in serum and cerebral spinal fluid. Main results revealed that ICH induced a delayed increase in GFAP+ cells in the sensorimotor cortex, as compared to the striatum, although the pattern of GFAP expression was similar in both structures. Interestingly, the time-curve patterns of both S100B and CD11+ microglial cells differed between the cortex and striatum. Altogether, these results suggest a different dynamics of glial-associated changes in the cerebral cortex, suggesting it is a vulnerable structure and undergoes an independent secondary process of reactive glial plasticity following intracerebral hemorrhage.

Administration of Huperzia quadrifariata Extract, a Cholinesterase Inhibitory Alkaloid Mixture, has Neuroprotective Effects in a Rat Model of Cerebral Hypoxia-Ischemia.

Neonatal hypoxia-ischemia (HI) is an etiologic component of several neurologic pathologies associated to cognitive impairment. The mechanisms involved in HI-induced tissue damage start immediately after HI and extend for days. Acetylcholine is an important neurotransmitter in the central nervous system and exerts a protector effect on tissue damage by modulating inflammation, and cholinesterase inhibitors have shown neuroprotective properties and their action are often attributed to inhibition of the immune response. The administration of Huperzia quadrifariata alkaloid extract (HqAE), with potent and selective cholinesterase inhibitor properties, will reduce the HI induced behavioral deficits and tissue damage. A total of 84 newborn Wistar rat pups at post natal day 7 (PND7) were subjected to right carotid occlusion followed by 1 h of hypoxia (8% of O2) and i.p. injections of saline, vehicle or HqAE (10 mg/kg). Morris Water Maze and inhibitory avoidance tests were used to assess the cognitive function. Flow cytometry was performed at PND11. Histological analysis was performed at PND45. HqAE treatment was able to prevent the HI induced cognitive deficits in both tests and, at PND45, histological analysis showed that HqAE treatment reduced hippocampus tissue damage. Flow cytometry of the injured hippocampus revealed that the treatment was able to reduce cellular death and the number of infiltrating T cells. Altogether, these results show the therapeutic potential of the Huperzia quadrifariata alkaloid extract to prevent cognitive deficits and histological damage caused by neonatal hypoxia-ischemia, probably by reducing cellular death and T cell mobilization.

Longer hypoxia-ischemia periods to neonatal rats causes motor impairments and muscular changes.

Prematurity and hypoxia-ischemia (HI) can lead to movement disorders in infants. Considering that mild-moderate HI induced at postnatal day (PND) 3 has failed to produce motor disabilities similar to those seen in pre-term newborns, the main goal of the present study was to verify whether longer hypoxia periods would mimic motor function impairment, brain and muscle morphological alterations. Forty-nine Wistar rat pups of both sexes were randomly assigned to surgical control (CG) and HI groups. HI animals were submitted to the Levine-Rice model at PND 3, and exposed to 120 (HI-120'), 180 (HI-180') or 210 (HI-210') minutes of hypoxia (FiO2: 0.08). Sensorimotor function was assessed as from PND 35-45, by means of grasping strength, adhesive removal, cylinder and ladder walking tests. Histological staining was used to quantify the striatal volume and the cross-sectional area (CSA) of skeletal muscles. Cylinder and adhesive removal test evidenced that HI-180' and HI-210' groups had asymmetrical use of the forepaws when compared to controls. HI animals showed a decrease in the step placement quality and an increase in step errors when compared to CG (P⩽0.05). Reduction in striatal volume correlates with behavioral assessment, HI-180' and HI-210' groups presented lower biceps brachii and tibialis anterior CSA. These results show that rats exposed to longer hypoxic periods at PND3 have encephalic and sensorimotor impairments that mimic those observed in preterm infants. Morphological changes in muscle tissue evidence a new pathophysiological characteristic of the HI model that might be of relevance for the study of sensorimotor deficits.

Human dental pulp stem cells transplantation combined with treadmill training in rats after traumatic spinal cord injury.

Spinal cord injury (SCI) is a disabling condition resulting in deficits of sensory and motor functions, and has no effective treatment. Considering that protocols with stem cell transplantation and treadmill training have shown promising results, the present study evaluated the effectiveness of stem cells from human exfoliated deciduous teeth (SHEDs) transplantation combined with treadmill training in rats with experimental spinal cord injury. Fifty-four Wistar rats were spinalized using NYU impactor. The rats were randomly distributed into 5 groups: Sham (laminectomy with no SCI, n=10); SCI (laminectomy followed by SCI, n=12); SHEDs (SCI treated with SHEDs, n=11); TT (SCI treated with treadmill training, n=11); SHEDs+TT (SCI treated with SHEDs and treadmill training; n=10). Treatment with SHEDs alone or in combination with treadmill training promoted functional recovery, reaching scores of 15 and 14, respectively, in the BBB scale, being different from the SCI group, which reached 11. SHEDs treatment was able to reduce the cystic cavity area and glial scar, increase neurofilament. Treadmill training alone had no functional effectiveness or tissue effects. In a second experiment, the SHEDs transplantation reduced the TNF-α levels in the cord tissue measured 6 h after the injury. Contrary to our hypothesis, treadmill training either alone or in combination, caused no functional improvement. However, SHEDs showed to be neuroprotective, by the reduction of TNF-α levels, the cystic cavity and the glial scar associated with the improvement of motor function after SCI. These results provide evidence that grafted SHEDs might be an effective therapy to spinal cord lesions, with possible anti-inflammatory action.

Human dental pulp stem cells transplantation combined with treadmill training in rats after traumatic spinal cord injury

Spinal cord injury (SCI) is a disabling condition resulting in deficits of sensory and motor functions, and has no effective treatment. Considering that protocols with stem cell transplantation and treadmill training have shown promising results, the present study evaluated the effectiveness of stem cells from human exfoliated deciduous teeth (SHEDs) transplantation combined with treadmill training in rats with experimental spinal cord injury. Fifty-four Wistar rats were spinalized using NYU impactor. The rats were randomly distributed into 5 groups: Sham (laminectomy with no SCI, n=10); SCI (laminectomy followed by SCI, n=12); SHEDs (SCI treated with SHEDs, n=11); TT (SCI treated with treadmill training, n=11); SHEDs+TT (SCI treated with SHEDs and treadmill training; n=10). Treatment with SHEDs alone or in combination with treadmill training promoted functional recovery, reaching scores of 15 and 14, respectively, in the BBB scale, being different from the SCI group, which reached 11. SHEDs treatment was able to reduce the cystic cavity area and glial scar, increase neurofilament. Treadmill training alone had no functional effectiveness or tissue effects. In a second experiment, the SHEDs transplantation reduced the TNF-α levels in the cord tissue measured 6 h after the injury. Contrary to our hypothesis, treadmill training either alone or in combination, caused no functional improvement. However, SHEDs showed to be neuroprotective, by the reduction of TNF-α levels, the cystic cavity and the glial scar associated with the improvement of motor function after SCI. These results provide evidence that grafted SHEDs might be an effective therapy to spinal cord lesions, with possible anti-inflammatory action.