Preventive effect of 8 weeks moderate training on susceptible colon cancer factor (Insulin Growth Factor I and Insulin Growth Factor Binding Protein 3 in rats)

摘要

Background & Aims : Malignant neoplasm of the colon wall or colon cancer (or colorectal cancer) is the fourth and third most common cancer in men and women worldwide, respectively. Risk factors for colon cancer are complex and the drug therapies did not have a great survival chance. Regarding the probable role of the physical activity in preventing the incidence and severity of cancer, the present study examined insulin-like growth factor-1 (IGF-I) and insulin-like growth factor binding protein 3 (IGFBP3) in an animal model of colon cancer. Material & Methods : Male Wistar rats were selected based on approved protocols undergoing treadmill exercise training at moderate intensity. Groups consisted of healthy controls and trained; and cancerous control and trained. In each group, at least 7 mice were used alternatively. Animals first underwent eight weeks of moderate-intensity training and then, through intraperitoneal injection of 1,2-Dimethylhydrazine (DMH), changes in the predisposing factors for colon cancer were investigated. In non-experimental groups, the experience of drug-carrier injection and treadmill adaptation was also performed. Four weeks after DMH injection, IGF-I and IGFBP3 levels were measured in animal serum. Anatomical evidence was provided to confirm colon cancer. Results : Besides anatomical evidence of colon cancer, assessing the IGF-I and IGFBP3 values using quantitative ELISA kits showed that serum levels of IGF-I in animals were significantly reduced with moderate intensity pre-training but serum levels of IGFBP3 increased significantly compared to their values in untrained animals. Conclusion : Considering the findings of longitudinal studies, the underlying factors of increasing the incidence and severity of cancer and its relation with hyperinsulinemia were considered. The Increase in IGF-I and decrease in IGFBP3 following hyperinsulinemia is likely to be a factor for increasing the susceptibility to colorectal cancer in these patients. The findings of this study, as well as other studies, suggest that physical activity by reducing IGF-I and increasing IGFBP3 can be effective in preventing colon cancer. Physical activity can be important as a non-pharmacological approach to reducing the severity and development of colon cancer.