O exercício físico melhora a sensibilidade à insulina de ratos expostos à fuma?a de cigarro

摘要

GOAL: Smoking can cause cardiovascular diseases and reduction on insulin sensitivity. This study evaluated the effect of smoking and associated moderate physical activity on the insulin sensitivity in the heart by GLUT4 gene expression. METHODS: Male Wistar rats were divided into 4 groups: (C) control, (Ex) exercised, (SS) sedentary smoker and (ES) exercised smoker. SS and ES groups were submitted to cigarette smoke exposition, 30 min/2x a day/60 days. Ex and EF groups performed running on a treadmill, during 60min/60 days. GLUT4 protein and mRNA contents analysis was performed by Western Blotting and RT-PCR, respectively. RESULTS: The results showed that neither smoking nor physical activity changed body weight (C: 364.7 ± 9.7, Ex: 372.4 ± 7.2, SS: 368.9 ± 6.7, ES: 376.4 ± 7.8 g) and heart weight (C: 1.12 ± 0.05; Ex: 1.16 ± 0.04; SS: 1.14 ± 0.05; ES: 1.19 ± 0,05g). Insulin sensitivity was reduced in sedentary smoker group, and exercise improved this condition (C: 3.7 ± 0.3; Ex: 5.28 ± 0.5 *; SS: 2.1 ± 0.7 *; ES: 4.8 ± 0.09 **; *P <0.05 vs C, ** P <0.05 vs. SS). mRNA and protein contents did not change among the groups. On the other hand, smoking caused reduction, and exercise provoked increase in GLUT4 total content per gram of heart (C: 119.72±9.98; Ex: 143.09±9.09; SS: 84.36±10.99*; ES: 132.18±11.40# AU/ g tissue, *P<0.05 vs C, #P<0.01 vs SS). CONCLUSION: We concluded that smoking reduces insulin sensitivity and the cardiac ability in uptaking glucose, which can be reversed by moderate physical exercise.