Autophagy activation attenuates the neurotoxicity of local anesthetics by decreasing caspase-3 activity in rats / A ativação autofágica atenua a neurotoxicidade dos anestésicos locais ao diminuir a atividade da caspase‐ 3 em ratos

Abstract Background and objectives The mechanisms by which local anesthetics cause neurotoxicity are very complicated. Apoptosis and autophagy are highly coordinated mechanisms that maintain cellular homeostasis against stress. Studies have shown that autophagy activation serves as a protective mechanism in vitro. However, whether it also plays the same role in vivo is unclear. The aim of this study was to explore the role of autophagy in local anesthetic-induced neurotoxicity and to elucidate the mechanism of neurotoxicity in an intrathecally injected rat model. Methods Eighteen healthy adult male Sprague-Dawley rats were randomly divided into three groups. Before receiving an intrathecal injection of 1% bupivacaine, each rat received an intraperitoneal injection of vehicle or rapamycin (1 mg.kg-1) once a day for 3 days. The pathological changes were examined by Haematoxylin and Eosin (HE) staining. Apoptosis was analysed by TdT-mediated dUTP Nick-End Labelling (TUNEL) staining. Caspase-3, Beclin1 and LC3 expression was examined by Immunohistochemical (IHC) staining. Beclin1 and LC3 expression and the LC3-II/LC3-I ratio were detected by western blot analysis. Results After bupivacaine was injected intrathecally, pathological damage occurred in spinal cord neurons, and the levels of apoptosis and caspase-3 increased. Enhancement of autophagy with rapamycin markedly alleviated the pathological changes and decreased the levels of apoptosis and caspase-3 while increasing the expression of LC3 and Beclin1 and the ratio of LC3-II to LC3-I. Conclusions Enhancement of autophagy decreases caspase-3-dependent apoptosis and improves neuronal survivalin vivo. Activation of autophagy may be a potential therapeutic strategy for local anaesthetic-induced neurotoxicity.

Resumo Introdução e objetivos Os mecanismos de neurotoxicidade dos anestésicos locais são complexos. A apoptose e a autofagia são mecanismos altamente organizados que mantêm a homeostase celular durante o estresse. Estudos revelam que a ativação da autofagia atua como mecanismo de proteção in vitro. Não está claro se a autofagia também desempenha essa função in vivo. O objetivo deste estudo foi analisar o papel da autofagia na neurotoxicidade induzida por anestésico local e esclarecer o mecanismo dessa neurotoxicidade utilizando um modelo de injeção intratecal em ratos. Métodos Dezoito ratos Sprague‐Dawley machos adultos saudáveis foram divididos aleatoriamente em três grupos. Antes de receber a injeção intratecal de bupivacaína a 1%, cada rato recebeu injeção intraperitoneal de veículo ou rapamicina (1 mg.kg‐1) uma vez ao dia durante 3 dias. As alterações patológicas foram examinadas por coloração com Hematoxilina e Eosina (HE). A apoptose foi analisada por coloração com o método dUTP Nick‐End Labeling (TUNEL) mediado por TdT. A expressão de caspase‐3, Beclin1 e LC3 foram examinadas por coloração Imunohistoquímica (IHQ). A expressão de Beclin1 e LC3 e a razão LC3‐II/LC3‐I foram detectadas por análise de western blot. Resultados Após a injeção intratecal de bupivacaína, ocorreu lesão patológica nos neurônios da medula espinhal e os níveis de apoptose e caspase‐3 aumentaram. A ativação da autofagia causada pela rapamicina mitigou de forma expressiva as alterações patológicas e diminuiu os níveis de apoptose e caspase‐3, aumentando a expressão de LC3 e Beclin1 e a razão LC3‐II/LC3‐I. Conclusões O aumento da autofagia diminui a apoptose dependente da caspase‐3 e melhora a sobrevivência neuronal in vivo. A ativação da autofagia pode ser uma estratégia terapêutica potencial para a neurotoxicidade induzida por anestésicos locais.

effects of Boswellia resin extract on dopaminergic cell line, SK-N-SH, against MPP[+]-induced neurotoxicity

Oxidative stress and neuroinflammation are involved in neurodegeneration procedure in Parkinson's disease. Recently, neuroprotective potential of Boswellia resin has been demonstrated. Therefore, this study examined whether administration of Boswellia resin would attenuate MPP+- induced neuronal death in SK-N-SH- cell line, a human dopaminergic neurons- in vitro. Boswellia resin extract was added to culture medium [10microg/ml] before and after exposure of SK-N-SH cell line to MPP+ [1000microM]. Cell viability and apoptosis features were assessed using MTT and Hoechst staining, respectively. Treatment with Boswellia resin 2 and 3h prior to MPP ° exposure and up to 60 minutes after MPP ° exposure significantly increased cell viability compare to untreated cells. Apoptotic features were also reduced significantly by Boswellia resin [10 microg/ml] compare to that of control untreated cells. Boswellia resin has neuroprotective effects on dopaminergic neurons which can be applicable in Parkinson's disease

Protective effects of N-Acetyl-L-cystein on 3,4-Methylene Dioxymethamphetamie-induced Neurotoxicity in Cerebellum of male rats

3-4, methylenedioxymethamphetamine [MDMA] causes apoptosis in nervous system and several studies suggest that oxidative stress contributes to MDMA-induced neurotoxicity. The aim of this study is to examine the effects of N-acetyl-L-Cystein [NAC] as an antioxidant on MDMA-induced apoptosis. 21 Sprague dawley male rats [200-250mg] were treated with MDMA [2x0,5mg/kg] or MDMA plus NAC [100mg/kg IP for 7 day]. After last administration of MDMA, rats were killed, cerebellum was removed and Bax and Bcl-2 expression was assessed by western blotting method. The results of this study showed that MDMA causes up-regulation of Bax and down-regulation of Bcl-2 and NAC administration attenuated MDMA-induced apoptosis. The present study suggests that NAC treatment may improve MDMA-induced neurotoxicity.

Aracnoides trabecular, piamadre espinal humana y anestesia subaracnoidea / Trabecular arachnoid membrane, human spinal piamater and subarachnoid anesthesia

En los textos de anestesiología se aportan pocos detalles sobre la aracnoides trabecular y la piamadre espinal humana, a pesar de ser estructuras íntimamente relacionadas con los anestésicos locales administrados en una anestesia subaracnoidea. Complicaciones tales como el síndrome de cauda equina y el síndrome de irritación radicular transitorio posterior a la realización de bloqueos subaracnoideos, sumado a la alta permeabilidad que ha sido asociada con la piamadre, nos ha motivado a investigar sobre la ultraestructura de estas meninges. Método. Las muestras estudiadas se tomaron de cadáveres recientes y fueron examinadas por microscopía electrónica de transmisión y de barrido. Resultados. El trabeculado aracnoideo rodeaba a las raíces nerviosas, a la médula y a los vasos que se encontraban dentro del espacio subaracnoideo, limitando zonas. La piamadre estaba formada por un plano celular y por un compartimiento subpial. En el plano celular existían perforaciones naturales, especialmente en la región del cono medular y en las raíces nerviosas. Conclusiones. La inyección accidental de anestésicos locales dentro de las fundas que formaban el trabeculado aracnoideo podría justificar una dilución inadecuada de estas soluciones y el origen de síndromes neurotóxicos transitorios o permanentes. La alta permeabilidad de la piamadre podría deberse, en parte, a la existencia de perforaciones naturales, las cuales facilitarían un pasaje rápido de las sustancias introducidas en el líquido cefalorraquídeo hacia las raíces nerviosas y la médula espinal. En este caso, la membrana basal ubicada por debajo de las fibras colágenas del compartimiento subpial sería la única estructura limitante previa al tejido glio-neuronal de la médula.

Few details are to be found in anesthesiology texts concerning the trabecular arachnoid membrane and the human spinal pia mater in spite of being structures that are intimately related to local anesthetics administered in subarachnoid anesthesia. We were driven to investigate the ultrastructure of these meninges by complications such as the cauda equina syndrome and the transitory radicular irritation syndrome following subarachnoid blocks, added to the high permeability associated to the pia mater. Method. The samples analyzed were taken from recently deceased cadavers and were examined under transmission and scanning electron microscopy. Results. The arachnoid trabeculation surrounded the nerve roots, the spinal cord and the vessels within the subarachnoid space, limiting areas. The pia mater was formed by a cellular plane and by a sub-pial compartment. There were natural perforations in the cellular plane, particularly in the medullar cone region and the nerve roots. Conclusions. Accidental injection of local anesthetics into the sheaths formed by arachnoid trabeculation could be the cause of inadequate dilution of these solutions and the source of transitory or permanent neurotoxic syndromes. The high permeability of the pia mater could be partly due to the existence of natural perforations, which enable the quick passage of the substances introduced in the cerebrospinal fluid into the nerve roots and spinal cord. ln this case, the basal membrane located underneath the collagen fibers of the subpial compartment would be the only limiting structure before the glioneural tissue of the spinal cord.

Os textos de anestesiologia fornecem poucos detalhes sobre a aracnóide trabecular e a pia-máter espinhal humana, apesar delas serem estruturas intimamente relacionadas com os anestésicos locais administrados em uma anestesia subaracnóidea. Complicações tais como a síndrome de cauda eqüina e a síndrome de irritação radicular transitória posterior a bloqueios subaracnóideosas quais se soma a alta permeabilidade, que tem sido associada à pia-máter -levou-nos a pesquisar a ultraestrutura dessas meninges. Método. As amostras estudadas foram coletadas de cadáveres recentes e examinadas por microscopia eletrónica de transmissão e de varredura. Resultados. A trabeculação aracnóidea rodea va as raízes nervosas, a medula e os vasos no interior do espaço subaracnóide, limitando zonas. A pia-máter estava formada por um plano celular e um espaço subpial. No plano celular existiam perfurações naturais, especialmente na regiáo do cone medular e nas raízes nervosas. Conclusóes. A injeção acidental de anestésicos locais no interior das coberturas que formavam a trabeculação aracnoidea poderia justificar uma diluição inadequada das soluções e a origem de síndromes neurotóxicas transitórias ou permanentes. A causa da alta permeabilidade da pia-máter seria, em parte, a existencia de perfurações naturais que facilitariam a rápida passagem das substancias introduzidas no líquido cefalorraquiano para as raizes nervosas e a medula espinhal. Neste caso, a membrana basal localizada abaixo das fibras colágenas do espaço subpial seria a única estrutura limitante anterior ao tecido glio-neuronal da medula.

Study of cyclosporine level at 2 hours after administration in preoperative kidney transplant recipients for prediction of postoperative optimal cyclosporine dose.

OBJECTIVE: Absorption profiling of cyclosporine is a current concept of drug monitoring. A single blood concentration measurement 2 hours after cyclosporine administration (C2) has been shown to be a good predictor of drug exposure and clinical outcome. The recommendation states that achieving the recommended target level of 1700 +/- 340 ng/ml within 3-5 days after renal transplantation is associated with a lower rate of acute rejection and nephrotoxicity. The high variation of pharmacokinetic profile and short limited time during early post-transplantation period make it hard to adjust the cyclosporine dose that can reach that target level on time. The present study was designed to be a method to predict the optimal pre-transplant CsA dose. MATERIAL AND METHOD: Eleven living-related kidney transplant recipients were recruited to receive cyclosporine and were monitored for C2 concentration during the 2 weeks before operation by the designed method. The pre-transplant empirical dose of 3.5 mg/kg/dose every 12 hours were assigned to all patients. The first predicted dose was estimated by using C2 concentration of 1,700 ng/mL. The first predicted dose was prescribed to the patients. The second predicted dose was estimated by using C2 concentration of the first predicted dose. All patients received the average of the first and the second predicted doses of cyclosporine within 12-24 hrs before transplantation and until the 3rd day after transplantation. RESULTS: Nine out of 11 patients (81.81%) reached the target C2 level on the 3rd day after transplantation without any serious side effect and complications. The most common side effect was nausea and a flushing sensation that usually abated with a later dose after transplantation. CONCLUSION: The early postoperative optimal cyclosporine dose can be effectively predicted by pre-transplant C2 measurement as conducted in the present study.