NLRP3 Activation Contributes to Memory Impairment in an Experimental Model of Pneumococcal Meningitis.

Bacterial meningitis is considered a life-threatening condition with high mortality rates. In response to the infection, signaling cascades, producing pro-inflammatory mediators trigger an exacerbated host immune response. Another inflammatory pathway occurs through the activation of inflammasomes. Studies highlight the role of the NLR family pyrin domain containing 3 (NLRP3) in central nervous system disorders commonly involved in neuroinflammation. We aimed to investigate the role of NLRP3 and its inhibitor MCC950 on neurochemical, immunological, and behavioral parameters in the early and late stages of experimental pneumococcal meningitis. For this, adult male Wistar rats received an intracisternal injection of Streptococcus pneumoniae or artificial cerebrospinal fluid as a placebo. The animals were divided into control/saline, control/MCC950, meningitis/saline, and meningitis/MCC950. Immediately after the meningitis induction, the animals received 140 ng/kg MCC950 via intracisternal injection. For the acute protocol, 24 h after induction, brain structures were collected to evaluate cytokines, NLRP3, and microglia. In the long-term group, the animals were submitted to open field and recognition of new objects tests at ten days after the meningitis induction. After the behavioral tests, the same markers were evaluated. The animals in the meningitis group at 24 h showed increased levels of cytokines, NLRP3, and IBA-1 expression, and the use of the MCC950 significantly reduced those levels. Although free from infection, ten days after meningitis induction, the animals in the meningitis group had elevated cytokine levels and demonstrated behavioral deficits; however, the single dose of NLRP3 inhibitor rescued the behavior deficits and decreased the brain inflammatory profile.

Pre-treatment and continuous administration of simvastatin during sepsis improve metabolic parameters and prevent CNS injuries in survivor rats.

Sepsis causes overproduction of inflammatory cytokines, organ dysfunction, and cognitive impairment in survivors. In addition to inflammation, metabolic changes occur according to the stage and severity of the disease. Understanding the role and place of metabolic disturbances in the pathophysiology of sepsis is essential to evaluate the framework of septic patients, predict the syndrome progress, and define the treatment strategies. We investigated the effect of simvastatin on the disease time course and on metabolic alterations, especially with respect to their possible consequences in the CNS of surviving rats. The animals of this study were weighed daily and followed for 10 days to determine the survival rate. In the first experiment, control or cecal ligation and puncture (CLP)-animals were randomized in 24 h, 48 h, and 10 days after septic induction, for bacterial load determination and quantification of cytokines. In the second experiment, control or CLP-animals were treated or not with simvastatin and randomized in the same three time points for cytokines quantification and assessment of their body metabolism and locomotor activity (at 48 h and 10 days), as well as the evaluation of cytoarchitecture and astrogliosis (at 10 days). The CLP-rats treated with simvastatin showed a reduction in plasma cytokines and improvement in metabolic parameters and locomotor activity, followed by minor alterations compatible with apoptosis and astrogliosis in the hippocampus and prefrontal cortex. These results suggest that the anti-inflammatory effect of simvastatin plays a crucial role in restoring energy production, maintaining a hypermetabolic state necessary for the recovery and survival of these CLP-rats.

Hyperbaric Oxygen Therapy Associated with Ventricular-Subcutaneous Shunt Promotes Neuroprotection in Young Hydrocephalic Rats.

Hydrocephalus is characterized by the accumulation of CSF within the cerebral ventricles and the subarachnoid space. Ventricular volume can progressively increase and generate serious damage to the nervous system, with cerebral hypoxia/ischemia as one of the most important factors involved. Hyperbaric oxygen therapy (HBOT) improves oxygen supply to tissues, which can reduce the progression of lesions secondary to ventricular enlargement. We evaluated whether HBOT associated with CSF diversion can promote neuroprotective effects to structures damaged by ventriculomegaly and understand its role. Seven-day-old male Wistar Hannover rats submitted to hydrocephalus by intracisternal injection of 15% kaolin were used. The animals were divided into six groups, with ten animals in each: control, control associated with hyperbaric therapy, hydrocephalic without treatment, hydrocephalic treated with hyperbaric oxygen therapy, hydrocephalic treated with CSF deviation, and hydrocephalic treated with hyperbaric oxygen therapy associated with CSF deviation. To assess the response to treatment, behavioral tests were performed such as modified Morris water maze and object recognition, evaluation by transcranial ultrasonography, histology by Hematoxylin-Eosin and Luxol Fast Blue, immunohistochemistry for GFAP, Ki-67, Caspase-3, COX-2, NeuN and SOD1, and biochemical ELISA assay for GFAP and MBP. The results show that the association of treatments exerts neuroprotective effects such as neurobehavioral improvement, preservation of periventricular structures, antioxidant effect, and reduction of damage resulting from ischemia and the neuroinflammatory process. We conclude that HBOT has the potential to be used as an adjuvant treatment to CSF deviation surgery in experimental hydrocephalus.

Corticosterone and Adrenocorticotrophic Hormone Secretion Is Recovered after Immune Challenge or Acute Restraint Stress in Sepsis Survivor Animals.

BACKGROUND: Clinical and experimental studies report a dysregulation of hypothalamus-pituitary-adrenal (HPA) axis during sepsis that causes impairment in hormone secretion in the late phase contributing for the pathophysiology of the disease. However, it is unclear whether this alteration persists even after the disease remission. METHODS: We evaluated the effect of an immune challenge or restraint stress on the hormone secretion of HPA axis in sepsis survivor rats. Sepsis was induced by cecal ligation-puncture (CLP) surgery. Naive or animals that survive 5 or 10 days after CLP were submitted to lipopolysaccharide (LPS) injection or restraint stress. After 60 min, blood was collected for plasma nitrate, cytokines, adrenocorticotropic hormone (ACTH), and corticosterone (CORT) and brain for synaptophysin and hypothalamic cytokines. RESULTS: Five days survivor animals showed increased plasma nitrate (p < 0.001) and interleukin (IL)-1ß levels (p < 0.05) that were abolished in the 10 days survivors. In the hypothalamus of both survivors, the reverse was seen with IL-6 increased (p < 0.01), while IL-1ß did not show any alteration. Synaptophysin expression was reduced in both survivors and did not change after any stimuli. Only the LPS administration increased plasma and/or inflammatory mediators levels in both groups (survivors and naive) being apparently lower in the survivors. There was no difference in the increased secretion pattern of ACTH and CORT observed in the naive and sepsis survivor animals submitted to immune challenge or restraint stress. CONCLUSION: We conclude that the HPA axis is already recovered soon after 5 days of sepsis induction responding with normal secretion of ACTH and CORT when required.

Microglial Activation Modulates Neuroendocrine Secretion During Experimental Sepsis.

Sepsis promotes an inflammatory state in the central nervous system (CNS) that may cause autonomic, cognitive, and endocrine changes. Microglia, a resident immune cell of the CNS, is activated in several brain regions during sepsis, suggesting its participation in the central alterations observed in this disease. In this study, we aimed to investigate the role of microglial activation in the neuroendocrine system functions during systemic inflammation. Wistar rats received an intracerebroventricular injection of the microglial activation inhibitor minocycline (100 µg/animal), shortly before sepsis induction by cecal ligation and puncture. At 6 and 24 h after surgery, hormonal parameters, central and peripheral inflammation, and markers of apoptosis and synaptic function in the hypothalamus were analyzed. The administration of minocycline decreased the production of inflammatory mediators and the expression of cell death markers, especially in the late phase of sepsis (24 h). With respect to the endocrine parameters, microglial inhibition caused a decrease in oxytocin and an increase in corticosterone and vasopressin plasma levels in the early phase of sepsis (6 h), while in the late phase, we observed decreased oxytocin and increased ACTH and corticosterone levels compared to septic animals that did not receive minocycline. Prolactin levels were not affected by minocycline administration. The results indicate that microglial activation differentially modulates the secretion of several hormones and that this process is associated with inflammatory mediators produced both centrally and peripherally.

Simvastatin Prevents Long-Term Cognitive Deficits in Sepsis Survivor Rats by Reducing Neuroinflammation and Neurodegeneration.

Sepsis-associated encephalopathy causes brain dysfunction that can result in cognitive impairments in sepsis survivor patients. In previous work, we showed that simvastatin attenuated oxidative stress in brain structures related to memory in septic rats. However, there is still a need to evaluate the long-term impact of simvastatin administration on brain neurodegenerative processes and cognitive damage in sepsis survivors. Here, we investigated the possible neuroprotective role of simvastatin in neuroinflammation, and neurodegeneration conditions of brain structures related to memory in rats at 10 days after sepsis survival. Male Wistar rats (250-300 g) were submitted to cecal ligation and puncture (CLP, n = 42) or remained as non-manipulated (naïve, n = 30). Both groups were treated (before and after the surgery) by gavage with simvastatin (20 mg/kg) or an equivalent volume of saline and observed for 10 days. Simvastatin-treated rats that survived to sepsis showed a reduction in the levels of nitrate, IL1-ß, and IL-6 and an increase in Bcl-2 protein expression in the prefrontal cortex and hippocampus, and synaptophysin only in the hippocampus. Immunofluorescence revealed a reduction of glial activation, neurodegeneration, apoptosis, and amyloid aggregates confirmed by quantification of GFAP, Iba-1, phospho Ser396-tau, total tau, cleaved caspase-3, and thioflavin-S in the prefrontal cortex and hippocampus. In addition, treated animals presented better performance in tasks involving habituation memory, discriminative, and aversive memory. These results suggest that statins exert a neuroprotective role by upregulation of the Bcl-2 and gliosis reduction, which may prevent the cognitive deficit observed in sepsis survivor animals.

Sepsis-induced encephalopathy impairs descending nociceptive pathways in rats.

Sepsis-associated encephalopathy (SAE) is a significant problem in patients with sepsis, and it is associated with a decrease in cognitive and sensitivity capability induced by systemic inflammation. SAE is implicated in reversible brain damage of several regions related to cognition, emotion, and sensation; however, it is not well established if it could affect brain regions associated with nociceptive modulation. Here were evaluated the nociceptive thresholds in rats with systemic inflammation induced by cecal ligation puncture (CLP). After 24 h of CLP, it was observed an increase in nociceptive threshold in all tests. Periaqueductal gray, rostroventral medulla, critical regions for descending nociceptive modulation, were evaluated and showed enhanced pro-inflammatory cytokines as well as glial activation. These results suggest that systemic inflammation could compromise descending facilitatory pathways, impairing nociceptive sensory functioning.

HSP-Target of Therapeutic Agents in Sepsis Treatment.

Sepsis is a syndrome characterized by a dysregulated inflammatory response, cellular stress, and organ injury. Sepsis is the main cause of death in intensive care units worldwide, creating need for research and new therapeutic strategies. Heat shock protein (HSP) analyses have recently been developed in the context of sepsis. HSPs have a cytoprotection role in stress conditions, signal to immune cells, and activate the inflammatory response. Hence, HSP analyses have become an important focus in sepsis research, including the investigation of HSPs targeted by therapeutic agents used in sepsis treatment. Many therapeutic agents have been tested, and their HSP modulation showed promising results. Nonetheless, the heterogeneity in experimental designs and the diversity in therapeutic agents used make it difficult to understand their efficacy in sepsis treatment. Therefore, future investigations should include the analysis of parameters related to the early and late immune response in sepsis, HSP localization (intra or extracellular), and time to the onset of treatment after sepsis. They also should consider the differences in experimental sepsis models. In this review, we present the main results of studies on therapeutic agents in targeting HSPs in sepsis treatment. We also discuss limitations and possibilities for future investigations regarding HSP modulators.

Kaolin-induced hydrocephalus causes acetylcholinesterase activity dysfunction following hypothalamic damage in infant rats.

In hydrocephalus, the progressive accumulation of cerebrospinal fluid (CSF) causes dilatation of the lateral ventricles affecting the third ventricle and diencephalic structures such as the hypothalamus. These structures play a key role in the regulation of several neurovegetative functions by the production of the hormones. Since endocrine disturbances are commonly observed in hydrocephalic children, we investigated the impact of progressive ventricular dilation on the hypothalamus of infant rats submitted to kaolin-induced hydrocephalus. Seven-day-old infant rats were submitted to hydrocephalus induction by kaolin 20% injection method. After 14 days, the animals were decapitated and brain was collected to analyze mitochondrial function, neuronal activity by acetylcholinesterase (AChE) enzyme, oxidative damage, glial activation, and, neurotransmission-related proteins and anti-apoptotic processes in the hypothalamus. The hydrocephalic animals showed reduction in respiratory rates in the States of phosphorylation (P < 0.01) and non-phosphorylation (P < 0.05); increase in AChE activity in both the cytosol (P < 0.05) and the membrane (P < 0.01); decrease in synaptophysin (P < 0.05) and Bcl-2 (P < 0.05) contents and; increase in protein carbonyl (P < 0.01), GFAP (P < 0.01) and Iba-1 (P < 0.05) levels. The results demonstrate that ventricular dilation causes hypothalamic damage characterized by cholinergic dysfunction and suggests further investigation of the synthesis and secretion of hormones to generate new approaches and to assist in the treatment of hydrocephalic patients with hormonal alterations.

Neuroprotective action of Eicosapentaenoic (EPA) and Docosahexaenoic (DHA) acids on Paraquat intoxication in Drosophila melanogaster.

Several studies have shown the protective effects of dietary enrichment of omega-3 (ω-3) long-chain fatty acids in several animal models of neurodegenerative diseases. Here we investigate if eicosapentaenoic (EPA) and Docosahexaenoic (DHA) acids (ω-3) protect against neurodegeneration mediated by the exposure to a widely used herbicide Paraquat (PQ) (1,1'-dimethyl-4-4'-bipyridinium dichloride), focusing on mitochondrial metabolism using Drosophila melanogaster as a model. Dietary ingestion of PQ for 3 days resulted in the loss of citrate synthase content, respiratory capacity impairment and exacerbated H2O2 production per mitochondrial unit related to complex I dysfunction, and high lactate accumulation in fly heads. PQ intoxication lead to 1) the loss of ELAV (embryonic lethal abnormal vision) and α-spectrin, essential proteins of neuronal viability and synaptic stability; 2) increased gamma-secretase activity, an enzyme related to APP release; and 3) increased the amyloid fibrils contents. All these toxic effects induced by PQ were prevented by concomitant dietary ingestion of EPA/DHA, suggesting that a neuroprotective effect of ω-3 also involves mitochondrial protection. In conclusion, concomitant EPA and DHA ingestion protects against PQ-induced neuronal and mitochondrial dysfunctions frequently found in neurodegenerative processes reinforcing its protective role against environmental neurodegenerative diseases.

Acupuncture at ST36 exerts neuroprotective effects via inhibition of reactive astrogliosis in infantile rats with hydrocephalus.

BACKGROUND: Acupuncture has been associated with improved cerebral circulation, analgesia, neuromodulatory function and neurogenesis. In particular, acupuncture at ST36 has been widely used in several central nervous system (CNS) disorders, including neurodegenerative diseases. However, its effects on hydrocephalus have not been studied. Our aim was to evaluate the effects of acupuncture at ST36 on behaviour, motor development and reactive astrogliosis in infantile rats with hydrocephalus. METHODS: Hydrocephalus was induced in sixteen 7-day-old pup rats by injection of 20% kaolin into the cisterna magna. One day after hydrocephalus induction, acupuncture was applied once daily (for 30 min) for a total of 21 days in eight randomly selected animals (HAc group) while the remaining eight remained untreated (H group). An additional eight healthy animals were included as controls (C group). All animals were weighed daily and, from the fifth day after hydrocephalus induction, underwent MRI to determine the ventricular ratio (VR). Rats were also exposed to modified open-field tests every 3 days until the end of the experiment. After 21 days all the animals were euthanased and their brains removed for histology and immunohistochemistry. RESULTS: Hydrocephalic rats showed an increase in VR when compared with control rats (P<0.01). In addition, these animals exhibited delayed weight gain, which was attenuated with acupuncture treatment. Hydrocephalic animals treated with acupuncture performed better in open field tests (P<0.05), and had a reduction in reactive astrocyte cell density in the corpus callosum and external capsule, as assessed by GFAP (glial fibrillary acidic protein) immunohistochemistry (P<0.05). CONCLUSIONS: These findings indicate that acupuncture at ST36 has a neuroprotective potential mediated, in part, by inhibition of astrogliosis.

Impairment of osmotic challenge-induced neurohypophyseal hormones secretion in sepsis survivor rats.

BACKGROUND/PURPOSE: Recent studies have reported that sepsis survivors show impaired central nervous system functions. The osmoregulation in this post-sepsis condition has not been well investigated. In the present study, we evaluated the secretion of neurohypophyseal hormones, arginine vasopressin (AVP) and oxytocin (OT), and water intake induced by osmotic challenge in survivor rats. METHODS: Wistar rats were submitted to sepsis by cecal ligation and puncture (CLP). Five days after CLP surgery, the survivor and naive animals were stimulated with an osmotic challenge consisting of hypertonic saline administration. Thirty minutes later, blood and brain were collected for determination of osmolality, nitrite, interleukin (IL)-1ß, IL-6, AVP and OT levels and c-fos expression analysis of hypothalamic supraoptic nuclei (SON), respectively. In another set of sepsis survivor animals, water intake was measured for 240 min after the osmotic stimulus. RESULTS: High levels of nitrite and IL-1ß, but not IL-6, were found in the plasma of sepsis survivors and this long-term systemic inflammation was not altered by the osmotic challenge. Moreover, the AVP and OT secretion (but not the osmolality) and c-fos expression in SON were significantly attenuated in CLP survivor animals. Additionally, there was no alteration in the water intake response induced by osmotic challenge in the sepsis survivor group. CONCLUSION: The results suggest that the inflammatory components mediated a persistent impairment in the component of the osmoregulatory reflex affecting the secretion of neurohypophyseal hormones in sepsis survivor animals.

Environmental enrichment reduces brain damage in hydrocephalic immature rats.

PURPOSE: We investigate the effects of environmental enrichment (EE) on morphological alterations in different brain structures of pup rats submitted to hydrocephalus condition. METHODS: Hydrocephalus was induced in 7-day-old pup rats by injection of 20% kaolin into the cisterna magna. Ventricular dilatation and magnetization transfer to analyze myelin were assessed by magnetic resonance. Hydrocephalic and control rats exposed to EE (n = 10 per group) were housed in cages with a tunnel, ramp, and colored plastic balls that would emit sound when touched. The walls of the housing were decorated with colored adhesive tape. Moreover, tactile and auditory stimulation was performed daily throughout the experiment. Hydrocephalic and control rats not exposed to EE (n = 10 per group) were allocated singly in standard cages. All animals were weighed daily and exposed to open-field conditions every 2 days until the end of the experiment when they were sacrificed and the brains removed for histology and immunohistochemistry. Solochrome cyanine staining was performed to assess the thickness of the corpus callosum. The glial fibrillary acidic protein method was used to evaluate reactive astrocytes, and the Ki67 method to assess cellular proliferation in the subventricular zone. RESULTS: The hydrocephalic animals exposed to EE showed better performance in Open Field tests (p < 0.05), while presenting lower weight gain. In addition, these animals showed better myelination as revealed by magnetization transfer (p < 0.05). Finally, the EE group showed a reduction in reactive astrocytes by means of glial fibrillary acidic protein immunostaining and preservation of the proliferation potential of progenitor cells. CONCLUSION: The results suggest that EE can protect the developing brain against damaging effects caused by hydrocephalus.

Curcumin suppresses inflammatory cytokines and heat shock protein 70 release and improves metabolic parameters during experimental sepsis.

CONTEXT: Curcumin has been reported to have anti-inflammatory, antioxidant and hypoglycaemic properties, besides reducing mortality in sepsis. OBJECTIVE: This study evaluates the biological activities of a curcumin dispersion formulated by spray-drying in experimental sepsis. MATERIALS AND METHODS: Male Wistar rats were subjected to sepsis by caecal ligation and puncture (CLP), controls were sham operated. The animals were treated with curcumin dispersion (100 mg/kg, p.o.) or water for 7 days prior to CLP and at 2 h after surgery. One group was used to analyze curcumin absorption through HPLC; another had the survival rate assessed during 48 h; and from a third group, blood was collected by decapitation to analyze metabolic and inflammatory parameters. RESULTS: The plasma curcumin levels reached 2.5 ng/mL at 4 h, dropped significantly (p < 0.001) at 6 h (1.2 ng/mL), and were undetectable at 24 h in both groups. Curcumin temporarily increased the survival rate of the septic rats by 20%. Moreover, it attenuated glycaemia (p < 0.05) and volemia (p < 0.05) alterations typically observed during sepsis, and decreased the levels of the proinflammatory cytokines IL-1ß and IL-6 in plasma (p < 0.001) and peritoneal lavage fluid (p < 0.05) of septic rats. Serum HSP70 levels were decreased (p < 0.01) at 24 h after CLP. DISCUSSION AND CONCLUSION: Our results show that the curcumin dispersion dose employed was not detrimental to the septic rats. In fact, it temporarily increased their survival rate, improved important metabolic parameters, reduced proinflammatory cytokines and HSP70 production.

Edaravone reduces astrogliosis and apoptosis in young rats with kaolin-induced hydrocephalus.

PURPOSE: We investigated the possible neuroprotective effects of the free radical scavenger edaravone in experimental hydrocephalus. METHODS: Seven-day-old Wistar rats were divided into three groups: control group (C), untreated hydrocephalic (H), and hydrocephalic treated with edaravone (EH). The H and EH groups were subjected to hydrocephalus induction by 20% kaolin intracisternal injection. The edaravone (20 mg/kg) was administered daily for 14 days from the induction of hydrocephalus. All animals were daily weighed and submitted to behavioral test and assessment by magnetic resonance imaging. After 14 days, the animals were sacrificed and the brain was removed for histological, immunohistochemical, and biochemical studies. RESULTS: The gain weight was similar between groups from the ninth post-induction day. The open field test performance of EH group was better (p < 0.05) as compared to untreated hydrocephalic animals. Hydrocephalic animals (H and EH) showed ventricular ratio values were higher (p < 0.05), whereas magnetization transfer values were lower (p < 0.05), as compared to control animals. Astrocyte activity (glial fibrillary acidic protein) and apoptotic cells (caspase-3) of EH group were decreased on the corpus callosum (p > 0.01), germinal matrix (p > 0.05), and cerebral cortex (p > 0.05), as compared to H group. CONCLUSIONS: We have demonstrated that administration of edaravone for 14 consecutive days after induction of hydrocephalus reduced astrocyte activity and that it has some beneficial effects over apoptotic cell death.

Brain Oxidative Stress During Experimental Sepsis Is Attenuated by Simvastatin Administration.

During sepsis, brain damage is associated with oxidative stress due to overproduction of reactive oxygen species (ROS). Although there are recent reports about the benefits of statins in experimental sepsis and endotoxemia in peripheral organs, little is known about their effects in the CNS. Here, we investigated the antioxidant properties of simvastatin and its possible neuroprotective role during experimental sepsis. Male Wistar rats (250-300 g) were submitted to cecal ligation and puncture (CLP, n = 34) or remained as non-manipulated (naive, n = 34). Both groups were treated by gavage with simvastatin (20 mg/kg) or an equivalent volume of saline. The animals submitted to CLP were treated 4 days before and 48 h after surgery. One animal group was decapitated and the blood and brain were collected to quantify plasma levels of cytokines and assess astrogliosis and apoptosis in the prefrontal cortex and hippocampus. Another group was perfused with PBS (0.01 M), and the same brain structures were dissected to analyze oxidative damage. The CLP rats treated with simvastatin showed a reduction in nitric oxide (P < 0.05), IL1-ß (P < 0.001), IL-6 (P < 0.01), and TBARS levels (P < 0.001) and an increase in catalase activity (P < 0.01), citrate synthase enzyme (P < 0.05), and normalized GSH/GSSG ratio. In addition, the histopathological analysis showed a reduction (P < 0.001) in reactive astrocytes and caspase 3-positive apoptotic cells. The results suggest a possible neuroprotective effect of simvastatin in structures responsible for spatial learning and memory and indicate the need for behavioral studies evaluating the impact on cognitive damage, as frequently seen in patients surviving sepsis.

Vasopressin Impairment During Sepsis Is Associated with Hypothalamic Intrinsic Apoptotic Pathway and Microglial Activation.

Previous studies have shown that in the early phase of sepsis, the plasma concentration of arginine vasopressin (AVP) is increased, but in the late phase, its levels remain inadequately low, despite of persistent hypotension. One hypothesis suggested for this relative deficiency is apoptosis of vasopressinergic neurons. Here, we investigated apoptosis pathways in the hypothalamus during sepsis, as well as mechanisms underlying this process. Male Wistar rats were submitted to sepsis by cecal ligation and puncture (CLP) or nonmanipulated (naive) as control. After 6 and 24 h, the animals were decapitated and brain and blood were collected to assess hypothalamic apoptotic markers, IFN-γ plasma levels, and evidence for breakdown of the blood-brain barrier (BBB). Sepsis caused a decrease in mitochondrial antiapoptotic proteins (Bcl-2, Bcl-xL) in the hypothalamus, but had no effect on markers of cell death mediated by death receptors or immune cells. In the supraoptic nuclei of these animals, microglia morphology was consistent with activation, associated with an increase in plasma IFN-γ. A transitory breakdown of BBB in the hypothalamus was seen at 6 h following CLP. The results indicate that the intrinsic but not extrinsic apoptosis pathway is involved in the cell death observed in vasopressinergic neurons, and that this condition is temporally associated with microglial activation and BBB leaking.

Camellia sinensis neuroprotective role in experimentally induced hydrocephalus in Wistar rats.

PURPOSE: This study tested possible neuroprotective effects of Camellia sinensis-extracted polyphenols in experimental hydrocephalus in young rats. METHODS: Seven-day-old Wistar rats were used in this study. Pups were subjected to hydrocephalus induction by 20 % kaolin intracisternal injection. The polyphenol was administered intraperitoneally for 9 or 20 days from the induction of hydrocephalus. Clinical observations and behavioral tests were performed once a day. The animals, deeply anesthetized, were sacrificed by cardiac perfusion with saline 10 or 21 days after induction of hydrocephalus and their brains were removed. Preparations were made for histological analysis by hematoxylin and eosin, solochrome-cyanine, and immunohistochemistry for GFAP. RESULTS: Histopathological analysis showed that animals treated with the polyphenol for 9 consecutive days displayed reduction on astrocyte activity on the corpus callosum and external capsule, shown by GFAP immunostaining. They also displayed thicker and myelinated corpus callosum, exhibiting a more intense solochrome-cyanine blue staining. CONCLUSION: Although these results demonstrate a possible neuroprotective effect at the initial onset of the disease, additional studies should be performed to obtain an effective and safe therapy for deeper studies in clinical trials.

Sciatic nerve regeneration in rats by a nerve conduit engineering with a membrane derived from natural latex.

PURPOSE: To evaluate the capacity of natural latex membrane to accelerate and improve the regeneration quality of the of rat sciatic nerves. METHODS: Forty male adult Wistar rats were used, anesthetized and operated to cut the sciatic nerve and receive an autograft or a conduit made with a membrane derived from natural latex (Hevea brasiliensis). Four or eight weeks after surgery, to investigate motor nerve recovery, we analyzed the neurological function by walking pattern (footprints analysis and computerized treadmill), electrophysiological evaluation and histological analysis of regenerated nerve (autologous nerve graft or tissue cables between the nerve stumps), and anterior tibial and gastrocnemius muscles. RESULTS: All functional and morphological analysis showed that the rats transplanted with latex conduit had a better neurological recovery than those operated with autologous nerve: quality of footprints, performance on treadmill (p<0.01), electrophysiological response (p<0.05), and quality of histological aspects on neural regeneration. CONCLUSION: The data reported showed behavioral and functional recovery in rats implanted with latex conduit for sciatic nerve repair, supporting a complete morphological and physiological regeneration of the nerve.

Sciatic nerve regeneration in rats by a nerve conduit engineering with a membrane derived from natural latex / Regeneração do nervo ciático em ratos através de um conduto confeccionado com uma membrana de látex natural

PURPOSE: To evaluate the capacity of natural latex membrane to accelerate and improve the regeneration quality of the of rat sciatic nerves. METHODS: Forty male adult Wistar rats were used, anesthetized and operated to cut the sciatic nerve and receive an autograft or a conduit made with a membrane derived from natural latex (Hevea brasiliensis). Four or eight weeks after surgery, to investigate motor nerve recovery, we analyzed the neurological function by walking pattern (footprints analysis and computerized treadmill), electrophysiological evaluation and histological analysis of regenerated nerve (autologous nerve graft or tissue cables between the nerve stumps), and anterior tibial and gastrocnemius muscles. RESULTS: All functional and morphological analysis showed that the rats transplanted with latex conduit had a better neurological recovery than those operated with autologous nerve: quality of footprints, performance on treadmill (p<0.01), electrophysiological response (p<0.05), and quality of histological aspects on neural regeneration. CONCLUSION: The data reported showed behavioral and functional recovery in rats implanted with latex conduit for sciatic nerve repair, supporting a complete morphological and physiological regeneration of the nerve.

OBJETIVO: Avaliar a capacidade de uma membrana de látex natural em acelerar e melhorar a qualidade da regeneração do nervo ciático seccionado de ratos. MÉTODOS: Foram utilizados 40 ratos machos adultos da linhagem Wistar, anestesiados e operados com autoenxerto ou com interposição de um tubo confeccionado com uma membrana derivada do latex natural (Havea brasiliensis). Quatro ou oito semanas após a cirurgia, para investigar a recuperação motora do nervo, foram analisadas a função neurológica através do padrão da marcha (análise das pegadas e esteira computadorizada), avaliação eletrofisiológica e análise histológica do nervo regenerado (enxerto de nervo autólogo ou formação de nervo novo entre os cotos nervosos) e músculos gastrocnêmio e tibial anterior. RESULTADOS: Todas as análises morfológicas e funcionais demonstraram que os ratos transplantados com o conduto de látex tiveram recuperação melhor do que aqueles operados com nervo autólogo: qualidade das pegadas impressas, desempenho em esteira (p<0,01), resposta eletrofisiológica (p<0,05), e qualidade histológica da regeneração nervosa. CONCLUSÃO: Os dados apresentados demonstraram recuperação comportamental e funcional nos ratos implantados com o conduto de látex para a reparação do nervo ciático por meio de uma completa regeneração morfológica e fisiológica do nervo.