Exercise training prevents skeletal muscle damage in an experimental sepsis model

OBJECTIVE: Oxidative stress plays an important role in skeletal muscle damage in sepsis. Aerobic exercise can decrease oxidative stress and enhance antioxidant defenses. Therefore, it was hypothesized that aerobic exercise training before a sepsis stimulus could attenuate skeletal muscle damage by modulating oxidative stress. Thus, the aim of this study was to evaluate the effects of aerobic physical preconditioning on the different mechanisms that are involved in sepsis-induced myopathy. METHODS: Male Wistar rats were randomly assigned to either the untrained or trained group. The exercise training protocol consisted of an eight-week treadmill program. After the training protocol, the animals from both groups were randomly assigned to either a sham group or a cecal ligation and perforation surgery group. Thus, the groups were as follows: sham, cecal ligation and perforation, sham trained, and cecal ligation and perforation trained. Five days after surgery, the animals were euthanized and their soleus and plantaris muscles were harvested. Fiber cross-sectional area, creatine kinase, thiobarbituric acid reactive species, carbonyl, catalase and superoxide dismutase activities were measured. RESULTS: The fiber cross-sectional area was smaller, and the creatine kinase, thiobarbituric acid reactive species and carbonyl levels were higher in both muscles in the cecal ligation and perforation group than in the sham and cecal ligation and perforation trained groups. The muscle superoxide dismutase activity was higher in the cecal ligation and perforation trained group than in the sham and cecal ligation and perforation groups. The muscle catalase activity was lower in the cecal ligation and perforation group than in the sham group. CONCLUSION: In summary, aerobic physical preconditioning prevents atrophy, lipid peroxidation and protein oxidation and improves superoxide dismutase activity in the skeletal muscles of septic rats

Análise da relação entre a expressão da proteína VEGF e o estadiamento do câncer colorretal Analysis of relationship between VEGF protein expression and colorectal câncer staging

Os estudos em biologia molecular desenvolvidos nas últimas décadas, possibilitaram grandes avanços para uma maior compreensão da carcinogênese colorretal. Na década de 80 pesquisadores descobriram uma proteína com a capacidade de aumentar a permeabilidade dos vasos sangüíneos. Inicialmente esta proteína foi denominada como fator de permeabilidade vascular. Estudos posteriores correlacionaram esta proteína com o crescimento de novos vasos sangüíneos (angiogênese), quando passou a ser chamada de fator de crescimento endotelial vascular (VEGF). A proteína VEGF tem sido apontada como o principal fator promotor da angiogênese, dentre os vários já conhecidos. Neste trabalho o objetivo foi quantificar a proteína VEGF, e correlacionar os resultados com o estadiamento tumoral em amostras de adenocarcinoma colorretal. Foram incluídos 56 adenocarcinomas colorretais, nos quais a detecção da proteína VEGF foi realizada por imunoistoquímica através da construção de uma matriz tecidual e sua quantificação com análise digital de imagens assistida por computador. Nossos resultados não evidenciaram relação estatisticamente significativa entre a expressão da proteína VEGF e o estadiamento tumoral, ou presença e número de linfonodos comprometidos. Baseado no nível de expressão da proteína VEGF não foi possível inferir a presença de linfonodos comprometidos nas amostras analisadas.<br>Development of studies in molecular biology over the last decades has contributed for better knowledge about colorectal carcinogenesis. An important landmark in this process was the identification of a protein with effect on vascular permeability eventually named as vascular endothelial growth factor (VEGF), which seems to be essential for the angiogenesis activation of tumor development. The aim of this study was to assess the VEGF expression and correlate to tumor staging in colorectal cancer. Surgical specimens from 56 colorectal cancer patients were analyzed by immunohistochemistry for VEGF expression using a multitissue array and a computer-assisted image system. No significant result was found between VEGF expression and tumor staging or lymph nodes metastasis. We concluded that no predictive value for lymph nodes metastasis could be demonstrated by VEGF immunostaining in this study