Effects of propofol pretreatment on myocardial cell apoptosis and SERCA2 expression in rats with hepatic ischemia/reperfusion / Efeitos do pré-tratamento com propofol sobre a apoptose de células miocárdicas e expressão de SERCA2 em ratos com isquemia/reperfusão hepática

Abstract Introduction: Hepatic ischemia-reperfusion injury is a common pathophysiological process in liver surgery. Whether Propofol can reduce myocardial ischemia-reperfusion injury induced by hepatic ischemia-reperfusion injury in rats, together with related mechanisms, still needs further studies. Objective: To investigate if propofol would protect the myocardial cells from apoptosis with hepatic ischemia-reperfusion injury. Methods: Male Sprague-Dawley rats (n = 18) were randomly allocated into three groups: Sham Group (Group S, n = 6), Hepatic Ischemia-reperfusion Injury Group (Group IR, n = 6) and Propofol Group (Group P, n = 6). Group S was only subjected to laparotomy. Group IR was attained by ischemia for 30 min and reperfusion for 4 h. Group P was subjected identical insult as in Group IR with the administration of propofol started 10 min before ischemia with 120 mg.kg−1, following by continuous infusion at 20 mg.kg−1.h−1. Cell apoptosis was examined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. Endoplasmic reticulum Ca2+-ATPase2 (SERCA2) and cysteine-containing aspartic acid cleaved-caspase3 (cleaved-caspase3) were assayed by western blot and Altimeter polymerase chain reaction. Results: Apoptosis rate was increased, with mRNA and protein of SERCA2 down-regulated and cleaved-caspase3 up-regulated in Group IR compared with Group S (p < 0.01). Apoptosis rate was decreased, with mRNA and protein of SERCA2 up-regulated and cleaved-caspase3 down-regulated in Group P compared with Group IR (p < 0.01). Conclusions: Propofol can reduce hepatic ischemia-reperfusion injury-induced myocardial cell apoptosis, meanwhile, can up-regulate mRNA and protein of SERCA2 in rats.

Resumo Introdução: A lesão hepática por isquemia-reperfusão é um processo fisiopatológico comum em cirurgias hepáticas. Mais estudos ainda são necessários para avaliar se o propofol pode reduzir a lesão de isquemia-reperfusão miocárdica induzida pela lesão de isquemia-reperfusão hepática em ratos, juntamente com os mecanismos que estão relacionados. Objetivo: Investigar se propofol protege as células do miocárdio da apoptose com a lesão hepática por isquemia-reperfusão. Métodos: Ratos machos da raça Sprague-Dawley (n = 18) foram alocados aleatoriamente em três grupos: Grupo Sham (Grupo S, n = 6), Grupo Lesão Hepática por Isquemia-reperfusão (Grupo IR, n = 6) e Grupo Propofol (Grupo P, n = 6). O Grupo S foi submetido apenas à laparotomia. O grupo IR foi submetido à isquemia por 30 min e reperfusão por 4 h. O grupo P foi submetido à mesma isquemia do grupo IR, com a administração de 120 mg.kg-1 de propofol iniciada 10min antes da isquemia, seguida de infusão contínua a 20 mg.kg-1.h-1. A apoptose celular foi examinada por meio do ensaio de marcação de terminações dUTP pela deoxinucleotidil transferase. Retículo endoplasmático Ca2+-ATPase2 (SERCA2) e caspase-3 do ácido aspártico contendo cisteína (caspase-3 clivada) foram avaliados com o ensaio western blot e reação em cadeia da polimerase. Resultados: A taxa de apoptose foi maior com mRNA e proteína de SERCA2 regulados para baixo e caspase-3 clivada suprarregulada no Grupo IR, em comparação com o Grupo S (p < 0,01). A taxa de apoptose foi menor com mRNA e proteína de SERCA2 suprarregulada e caspase-3 clivada sub-regulada no Grupo P, em comparação com o Grupo IR (p < 0,01). Conclusões: O propofol pode reduzir a apoptose de células miocárdicas induzida por lesão hepática por isquemia-reperfusão. Entretanto, pode suprarregular o mRNA e a proteína de SERCA2 em ratos.

[Effects of propofol pretreatment on myocardial cell apoptosis and SERCA2 expression in rats with hepatic ischemia/reperfusion]. / Efeitos do pré­tratamento com propofol sobre a apoptose de células miocárdicas e expressão de SERCA2 em ratos com isquemia/reperfusão hepática.

INTRODUCTION: Hepatic ischemia-reperfusion injury is a common pathophysiological process in liver surgery. Whether Propofol can reduce myocardial ischemia-reperfusion injury induced by hepatic ischemia-reperfusion injury in rats, together with related mechanisms, still needs further studies. OBJECTIVE: To investigate if propofol would protect the myocardial cells from apoptosis with hepatic ischemia-reperfusion injury. METHODS: Male Sprague-Dawley rats (n=18) were randomly allocated into three groups: Sham Group (Group S, n=6), Hepatic Ischemia-reperfusion Injury Group (Group IR, n=6) and Propofol Group (Group P, n=6). Group S was only subjected to laparotomy. Group IR was attained by ischemia for 30min and reperfusion for 4h. Group P was subjected identical insult as in Group IR with the administration of propofol started 10min before ischemia with 120mg.kg-1, following by continuous infusion at 20mg.kg-1.h-1. Cell apoptosis was examined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. Endoplasmic reticulum Ca2+-ATPase2 (SERCA2) and cysteine-containing aspartic acid cleaved-caspase3 (cleaved-caspase3) were assayed by western blot and Altimeter polymerase chain reaction. RESULTS: Apoptosis rate was increased, with mRNA and protein of SERCA2 down-regulated and cleaved-caspase3 up-regulated in Group IR compared with Group S (p<0.01). Apoptosis rate was decreased, with mRNA and protein of SERCA2 up-regulated and cleaved-caspase3 down-regulated in Group P compared with Group IR (p<0.01). CONCLUSIONS: Propofol can reduce hepatic ischemia-reperfusion injury-induced myocardial cell apoptosis, meanwhile, can up-regulate mRNA and protein of SERCA2 in rats.

Effect of dexmedetomidine on acute lung injury in experimental ischemia-reperfusion model / Efeito de dexmedetomidina sobre lesão pulmonar aguda em modelo experimental de isquemia-reperfusão

Abstract Purpose: Ischemia-reperfusion injury is one of the consequences of tourniquet application for extremity surgery. The aim of the study was to establish the effect of dexmedetomidine on the acute lung injury following lower extremity experimental ischemia-reperfusion model in rats. Methods: Twenty-eight Wistar-Albino breed Rats were recruited after Ethics Committee approval and allocated into 4 groups, each with 7 subjects. Group 1 (SHAM) received only anesthesia. Group 2 (IR) had experienced 3 h of ischemia and 3 h of reperfusion using left lower extremity tourniquet after anesthesia application. Groups 3 (D-50) and 4 (D-100) had undergone the same procedures as in the Group 2, except for receiving 50 and 100 mg·kg-1, respectively, dexmedetomidine intraperitoneally 1 h before the tourniquet release. Blood samples were obtained for the analysis of tumor necrosing factor-α and interleukin-6. Pulmonary tissue samples were obtained for histological analysis. Results: No significant difference regarding blood tumor necrosing factor-α and interleukin-6 values was found among the groups, whereas pulmonary tissue injury scores revealed significant difference. Histological scores obtained from the Group 2 were significantly higher from those in the Groups 1, 3 and 4 with p-values 0.001 for each comparison. Moreover, Group 1 scores were found to be significantly lower than those in the Groups 3 and 4 with p-values 0.001 and 0.011, respectively. No significant difference was observed between the Groups 3 and 4. Conclusion: Dexmedetomidine is effective in reduction of the experimental ischemia-reperfusion induced pulmonary tissue injury in rats, formed by extremity tourniquet application.

Resumo Objetivo: A lesão de isquemia-reperfusão é uma das consequências da aplicação do torniquete em cirurgias de extremidades. O objetivo do estudo foi determinar o efeito de dexmedetomidina em lesão pulmonar aguda após modelo experimental de isquemia-reperfusão em extremidade inferior de ratos. Métodos: Vinte e oito ratos albinos Wistar foram recrutados após aprovação do Comitê de Ética e alocados em quatro grupos, cada um com sete indivíduos. O Grupo 1 (Sham) recebeu apenas anestesia. O Grupo 2 (IR) foi submetido a 3 horas de isquemia e 3 horas de reperfusão com o uso de torniquete em extremidade inferior após a aplicação da anestesia. Os grupos 3 (D-50) e 4 (D-100) foram submetidos aos mesmos procedimentos do Grupo 2, exceto por receberem 50 e 100 mg.kg-1 de dexmedetomidina, respectivamente, por via intraperitoneal uma hora antes da liberação do torniquete. Amostras de sangue foram coletadas para análise de TNF-α e Interleucina-6 (IL-6). Amostras de tecido pulmonar foram coletadas para análise histológica. Resultados: Não houve diferença significativa quanto aos valores sanguíneos de TNF-α e IL-6 entre os grupos, enquanto os escores de lesão em tecidos pulmonares revelaram diferença significativa. Os escores histológicos obtidos no Grupo 2 foram significativamente maiores do que os dos grupos 1, 3 e 4, com valores-p de 0,001 para cada comparação. Além disso, os escores do Grupo 1 foram significativamente menores do que os dos grupos 3 e 4, com valores-p de 0,001 e 0,011, respectivamente. Não houve diferença significativa entre os grupos 3 e 4. Conclusão: Dexmedetomidina mostrou eficácia na redução de lesão em tecido pulmonar induzida por isquemia-reperfusão experimental em ratos, ocasionada por aplicação de torniquete em extremidade.

Effect of dexmedetomidine on acute lung injury in experimental ischemia-reperfusion model.

PURPOSE: Ischemia-reperfusion injury is one of the consequences of tourniquet application for extremity surgery. The aim of the study was to establish the effect of dexmedetomidine on the acute lung injury following lower extremity experimental ischemia-reperfusion model in rats. METHODS: Twenty-eight Wistar-Albino breed Rats were recruited after Ethics Committee approval and allocated into 4 groups, each with 7 subjects. Group 1 (SHAM) received only anesthesia. Group 2 (IR) had experienced 3h of ischemia and 3h of reperfusion using left lower extremity tourniquet after anesthesia application. Groups 3 (D-50) and 4 (D-100) had undergone the same procedures as in the Group 2, except for receiving 50 and 100mg·kg-1, respectively, dexmedetomidine intraperitoneally 1h before the tourniquet release. Blood samples were obtained for the analysis of tumor necrosing factor-α and interleukin-6. Pulmonary tissue samples were obtained for histological analysis. RESULTS: No significant difference regarding blood tumor necrosing factor-α and interleukin-6 values was found among the groups, whereas pulmonary tissue injury scores revealed significant difference. Histological scores obtained from the Group 2 were significantly higher from those in the Groups 1, 3 and 4 with p-values 0.001 for each comparison. Moreover, Group 1 scores were found to be significantly lower than those in the Groups 3 and 4 with p-values 0.001 and 0.011, respectively. No significant difference was observed between the Groups 3 and 4. CONCLUSION: Dexmedetomidine is effective in reduction of the experimental ischemia-reperfusion induced pulmonary tissue injury in rats, formed by extremity tourniquet application.

[Effect of dexmedetomidine on acute lung injury in experimental ischemia-reperfusion model]. / Efeito de dexmedetomidina sobre lesão pulmonar aguda em modelo experimental de isquemia­reperfusão.

PURPOSE: Ischemia-reperfusion injury is one of the consequences of tourniquet application for extremity surgery. The aim of the study was to establish the effect of dexmedetomidine on the acute lung injury following lower extremity experimental ischemia-reperfusion model in rats. METHODS: Twenty-eight Wistar-Albino breed rats were recruited after Ethics Committee approval and allocated into 4 groups, each with 7 subjects. Group 1 (SHAM) received only anesthesia. Group 2 (IR) had experienced 3h of ischemia and 3h of reperfusion using left lower extremity tourniquet after anesthesia application. Groups 3 (D-50) and 4 (D-100) had undergone the same procedures as in the Group 2, except for receiving 50 and 100mg.kg-1, respectively, dexmedetomidine intraperitoneally 1h before the tourniquet release. Blood samples were obtained for the analysis of tumor necrosing factor-α and interleukin-6. Pulmonary tissue samples were obtained for histological analysis. RESULTS: No significant difference regarding blood tumor necrosing factor-α and interleukin-6 values was found among the groups, whereas pulmonary tissue injury scores revealed significant difference. Histological scores obtained from the Group 2 were significantly higher from those in the Groups 1, 3 and 4 with p-values 0.001 for each comparison. Moreover, Group 1 scores were found to be significantly lower than those in the Groups 3 and 4 with p-values 0.001 and 0.011, respectively. No significant difference was observed between the Groups 3 and 4. CONCLUSION: Dexmedetomidine is effective in reduction of the experimental ischemia-reperfusion induced pulmonary tissue injury in rats, formed by extremity tourniquet application.

Myocardial remote ischemic preconditioning: from pathophysiology to clinical application.

Short periods of myocardial ischemia followed by reperfusion induce a cardioprotective mechanism when the myocardium is subsequently subjected to a prolonged period of ischemia, a phenomenon known as ischemic preconditioning. As well as its application in the myocardium, ischemic preconditioning can also be induced by brief interruptions of blood flow to other organs, particularly skeletal muscle. Transient ischemia induced noninvasively by inflating a cuff on a limb, followed by reperfusion, helps reduce the damage caused to the myocardium by interruption of the coronary circulation. Remote ischemic preconditioning involves activation of humoral and/or neural pathways that open mitochondrial ATP-sensitive potassium channels in the myocardium and close mitochondrial permeability transition pores, making cardiomyocytes less vulnerable to ischemia-induced cell death. This cardioprotective mechanism is now being translated into clinical practice, with positive results in several clinical trials in coronary artery bypass surgery, surgical repair of abdominal aortic aneurysms, valve replacement surgery and percutaneous coronary intervention. However, certain factors weaken the subcellular mechanisms of preconditioning - age, comorbidities, medication, anesthetic protocol - and appear to explain the heterogeneity of results in some studies. Detailed understanding of the pathways involved in cardioprotection induced by ischemic preconditioning is expected to lead to the development of new drugs to reduce the consequences of prolonged ischemia.