The effects of a Camellia sinensis-derived polyphenolic in induced experimental hydrocephalus in Wistar rats

A hidrocefalia é uma síndrome complexa caracterizada pelo acúmulo de líquido cérebro-espinal no interior das cavidades ventriculares. Considerando a sua fisiopatologia de caráter multifatorial sendo um dos fatores envolvidos o estresse oxidativo desencadeado pela peroxidação lipídica e formação de radicais livres, este trabalho visa estudar o possível efeito neuroprotetor proveniente do polifenol galato de epigalocatequina (EGCG) na hidrocefalia experimental. Foram utilizados ratos da linhagem Wistar (N=56), com 7 dias de idade. Os filhotes foram submetidos à indução da hidrocefalia pelo método da injeção intracisternal de caulim a 20%. O polifenol foi administrado intraperitonealmente por 9 ou 20 dias consecutivos a partir da indução da hidrocefalia. Aferição do peso corporal diário e testes comportamentais foram realizados. Dez ou 21 dias após a indução da hidrocefalia os animais, profundamente anestesiados, foram sacrificados através da perfusão cardíaca com solução salina. Seus encéfalos foram removidos, fixados com paraformaldeído 3% em tampão fosfato 0,1M e processados para inclusão em parafina. Preparações histológicas foram realizadas para a análise por coloração hematoxilina eosina, solocromo-cianina e imunoistoquímica para GFAP e Ki67. Os diferentes parâmetros de avaliação demonstraram que os animais tratados com o polifenol por 9 dias consecutivos apresentaram redução da atividade astrocitária através da imunomarcação pelo GFAP no corpo caloso, cápsula externa e matriz germinativa; além de apresentarem corpo caloso mais espesso e mielinizado, exibindo uma tonalidade azul mais intensa evidenciada pela coloração solocromocianina. Apesar desses resultados demonstrarem um possível efeito neuroprotetor na fase inicial de instalação da doença, estudos adicionais devem ser realizados para obtenção de uma terapêutica eficiente e segura para o aprofundamento com testes clínicos.Hydrocephalus is a complex syndrome, characterized by the accumulation of cerebrospinal fluid in cerebral ventricles. Considering its multifactorial pathophysiology, one of the factors being the oxidative stress triggered by lipid peroxidation and free radical formation, this work aims to study the possible neuroprotective effect of the polyphenol epigallocatechin gallate (EGCG) in experimental hydrocephalus. Seven-day old Wistar rats (N=56) were used in this study. The pups were subjected to hydrocephalus induction by kaolin 20% through intracisternal injection. The polyphenol was administered intraperitoneally for 9 or 20 days from the induction of hydrocephalus. Measurement of daily body weight and behavioral tests were performed. The animals, deeply anesthetized, were sacrificed by cardiac perfusion with saline 10 or 21 days after induction of hydrocephalus. Their brains were removed, fixed with 3% paraformaldehyde in 0.1 M phosphate buffer, and processed for paraffin embedding. Preparations were made for histological analysis by hematoxylin and eosin, solochrome-cyanine and immunohistochemistry for GFAP and Ki67. The different evaluated parameters showed that animals treated with the polyphenol for 9 consecutive days displayed reduction on the reactive astrocytes GFAP immunostaining at the corpus callosum, external capsule and germinal matrix, also having thicker and more myelinated corpus callosum exhibiting a more intense blue staining by solocromo-cyanine. 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

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

0.1T magnetic resonance image in the study of experimental hydrocephalus in rats. Accuracy of the method in the measurements of the ventricular size Imagem de ressonância magnética de 1,0T no estudo da hidrocefalia experimental em ratos. Avaliação do método de medição do tamanho ventricular

PURPOSE: To investigate the accuracy of 1.0T Magnetic Resonance Imaging (MRI) to measure the ventricular size in experimental hydrocephalus in pup rats. METHODS: Wistar rats were subjected to hydrocephalus by intracisternal injection of 20% kaolin (n=13). Ten rats remained uninjected to be used as controls. At the endpoint of experiment animals were submitted to MRI of brain and killed. The ventricular size was assessed using three measures: ventricular ratio (VR), the cortical thickness (Cx) and the ventricles area (VA), performed on photographs of anatomical sections and MRI. RESULTS: The images obtained through MR present enough quality to show the lateral ventricular cavities but not to demonstrate the difference between the cortex and the white matter, as well as the details of the deep structures of the brain. There were no statistically differences between the measures on anatomical sections and MRI of VR and Cx (p=0.9946 and p=0.5992, respectively). There was difference between VA measured on anatomical sections and MRI (p<0.0001). CONCLUSION: The parameters obtained through 1.0T MRI were sufficient in quality to individualize the ventricular cavities and the cerebral cortex, and to calculate the ventricular ratio in hydrocephalus rats when compared to their respective anatomic slice.<br>OBJETIVO: Investigar a fidelidade das Imagens de Ressonância Magnética de 1,0T no estudo do tamanho ventricular na hidrocefalia experimental em ratos jovens. MÉTODOS: Ratos Wistar foram submetidos à hidrocefalia através da injeção intracisternal de caulim 20%. Dez animais permaneceram sem injeção para uso como controles. Ao final do experimento, os animais foram submetidos à Ressonância magnética de encéfalo e sacrificados. O tamanho ventricular foi avaliado por três medidas: razão ventricular (VR), espessura cortical (Cx) e área ventricular (VA), tomadas em fotografias das secções anatômicas e nas imagens de ressonância magnética (RM). RESULTADOS: As imagens por RM apresentaram qualidade suficiente para individualizar os ventriculos laterais, mas a distinção entre córtex e substância branca, bem como detalhamento das estruturas profundas do encéfalo não foram possíveis. Quando comparadas as medidas em seções anatômicas e RM, não houve diferença estatística entre as médias de razão ventricular e espessura cortical (p=0,9946 e p=0,5992, respectivamente). Houve diferença da área ventricular comparando-se as secções anatômicas e ressonância magnética (p<0,0001). CONCLUSÃO: Os parâmetros obtidos através de imagens da ressonância magnética de 1,0T foram suficientes para individualizar as cavidades ventriculares e o córtex cerebral, e para calcular o tamanho ventricular em ratos hidrocefálicos quando comparados aos seus respectivos cortes anatômicos

Employment of a Collagen Conduit Soaked in an Angiogenic Fraction Derived from Natural Latex in the Regeneration of Sciatic Nerve of Rats

AbstractPeripheral nerve injuries are very frequent in medical practice and although the use of autografts remains the standard procedure to repair the gap between the proximal and distal stumps, alternative techniques have been proposed to avoid complications to the donor site and speed up the nerve regeneration process. A membrane produced from natural latex has been used successfully both experimentally (angioplasties, esophagus neoformation, reconstruction of the ocular conjunctiva) and clinically (myringoplasties, treatment of skin ulcers), showing angiogenic potential and leading to tissue neoformation. The purpose of this study is to evaluate the capacity of a conduit made with collagen and soaked in an angiogenic protein extracted from latex in accelerating and improving the regeneration after surgically sectioning the rat sciatic nerve. Adult Wistar male rats had the sciatic nerve sectioned under anesthesia with a subtraction of a 10mm nerve fragment. Then they received an autograft implant (inverted nerve fragment) or the interposition into the nerve gap of a tube made up of that collagen and soaked in an angiogenic fraction derived from natural latex. At the endpoint of the experiments, the animals were submitted to neurological function evaluation, and killed by an overdose of anesthesia and exsanguination. The implants (collagen conduit or autograft) and the tibialis and gastrocnemius muscles were removed, fixed and processed with embedding in resin. Cross-section of implants and muscles were performed and prepared in histological slides to observation under light microscopy. Functional recovery was correlated with histopathological analysis. Bot

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.<br>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