Efeitos do sildenafil na lesão de músculo esquelético após isquemia e reperfusão em membros posteriores de ratos
Data
2012
Autores
Armstrong, Dinani Matoso Fialho de Oliveira 
Orientadores
Fagundes, Djalma José
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Fundamentação. Citrato de sildenafil (CS), um inibidor da enzima fosfodiesterase tipo5, é capaz de atenuar a lesão de isquemia e reperfusão (LIR) como pré-condicionamento farmacológico em coração, rim, fígado e cérebro. Contudo, os efeitos do CS na LIR em músculo esquelético não são definidos, especialmente quando administrado após o início da isquemia. Objetivo. Investigar os efeitos protetores do CS como póscondicionamento farmacológico na expressão da caspase 3 na LIR em músculo esquelético. Métodos. Ratos Wistar machos, adultos, foram randomizados para 4h ou 24h de reperfusão, distribuídos em 3 grupos: (1) grupo simulado (GS); (2) grupo controle (GCT); e (3) grupo do CS (GCS). No GCT e no GCS , a artéria femoral foi clampeada por 6 horas. Solução salina ou 1 mg/kg de CS foi administrado por gavagem 5h e meia após o início da isquemia. O músculo sóleo foi retirado 4h ou 24h após a
reperfusão. Um procedimento similar foi realizado no GS, porém sem isquemia. Depois da coloração imunohistoquímica, a razão entre as células positivas para a caspase-3 e as células negativas foi usada para a estimativa da apoptose. Os testes Wilcoxon rank-sum ou Kruskal-Wallis foram utilizados para avaliar as diferenças entre os grupos. Coeficiente de Correlação Intra-classe (CCI) e Bland-Altman plots foram utilizados para a reprodutibilidade inter-examinadores. Resultados. 18 animais foram incluídos no grupo de 4 horas de reperfusão e 21 animais no grupo de 24 horas de reperfusão. A relação média de caspase-3 foi de 0,18 ± 0,1 para todos grupos; 0,14 ± 0,06 para os grupos de 4h de reperfusão e 0,19 ± 0,08 para os grupos de 24h (p <0,05). GCS teve valores inferiores da expressão da caspase-3 em comparação com os grupos controle para a reperfusão tanto 4h e 24h. Contudo, a significância estatística foi atingida apenas para os grupos com reperfusão 24h. Conclusão. Citrato de sildenafil amenizou a LIR no músculo esquelético após o início da agressão isquêmica (pós-condicionamento farmacológico) neste modelo murino.
Background. Sildenafil citrate (SC), an inhibitor of phosphodiesterase type-5 enzyme, is capable of mitigating the degree of cellular damage associated with ischemiareperfusion injury (IRI) as pharmacologic preconditioning in heart, kidney, liver, and brain. However, the effect of SC in skeletal muscle is unclear, especially when used after the onset of the ischemic injury. Objective. We aim to investigate the protective effects of SC as pharmacologic postconditioning on skeletal muscle caspase-3 expression. Methods. Adult males Wistar rats were randomized for 4h or 24h reperfusion, distributed in three groups: (1) sham group (SG); (2) control group (CTG); and (3) sildenafil citrate group (SCG). In CTG and SCG, femoral artery was occluded for 6 hours. Saline or 1 mg/kg of SC was used 5½ hours after arterial occlusion. Soleus muscle samples were acquired 4h or 24h after the reperfusion. A similar procedure was performed to SG, but without artery occlusion. After immunohistochemistry analysis, the ratio between caspase-3 positive and negative cells was used for apoptosis estimative. Wilcoxon rank-sum test or Kruskal-Wallis test were used to assess differences among groups. Intra-class correlation coefficient (ICC) and Bland-Altman plots were used for inter-reader reproducibility. Results. A total of 18 animals were included in the 4h reperfusion groups and 21 animals in the 24h reperfusion groups. The mean caspase-3 ratio was 0.18±0.1 for the total cohort; 0.14±0.06 for the 4h reperfusion groups and 0.19±0.08 for the 24h groups (p<0.05). SCG had lower caspase-3 ratios compared to the control groups for both 4h and 24h reperfusion. However, statistical significance was shown only for the groups with 24h reperfusion. Conclusion. Sildenafil citrate limits IRI-induced cellular damage in skeletal muscle after the onset of the ischemic injury (pharmacological postconditioning) in this murine model.
Background. Sildenafil citrate (SC), an inhibitor of phosphodiesterase type-5 enzyme, is capable of mitigating the degree of cellular damage associated with ischemiareperfusion injury (IRI) as pharmacologic preconditioning in heart, kidney, liver, and brain. However, the effect of SC in skeletal muscle is unclear, especially when used after the onset of the ischemic injury. Objective. We aim to investigate the protective effects of SC as pharmacologic postconditioning on skeletal muscle caspase-3 expression. Methods. Adult males Wistar rats were randomized for 4h or 24h reperfusion, distributed in three groups: (1) sham group (SG); (2) control group (CTG); and (3) sildenafil citrate group (SCG). In CTG and SCG, femoral artery was occluded for 6 hours. Saline or 1 mg/kg of SC was used 5½ hours after arterial occlusion. Soleus muscle samples were acquired 4h or 24h after the reperfusion. A similar procedure was performed to SG, but without artery occlusion. After immunohistochemistry analysis, the ratio between caspase-3 positive and negative cells was used for apoptosis estimative. Wilcoxon rank-sum test or Kruskal-Wallis test were used to assess differences among groups. Intra-class correlation coefficient (ICC) and Bland-Altman plots were used for inter-reader reproducibility. Results. A total of 18 animals were included in the 4h reperfusion groups and 21 animals in the 24h reperfusion groups. The mean caspase-3 ratio was 0.18±0.1 for the total cohort; 0.14±0.06 for the 4h reperfusion groups and 0.19±0.08 for the 24h groups (p<0.05). SCG had lower caspase-3 ratios compared to the control groups for both 4h and 24h reperfusion. However, statistical significance was shown only for the groups with 24h reperfusion. Conclusion. Sildenafil citrate limits IRI-induced cellular damage in skeletal muscle after the onset of the ischemic injury (pharmacological postconditioning) in this murine model.
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Citação
ARMSTRONG, Dinani Matoso Fialho de Oliveira. Efeitos do sildenafil na lesão de músculo esquelético após isquemia e reperfusão em membros posteriores de ratos. Tese (Doutorado em Ciências) - Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, 2012.