ABSTRACT
Exercise training, an adjuvant therapy has a prophylactic effect on improvement of breast cancer. The purpose of this study was investigating the effect of endurance training on serum IL-8 concentration and tumor volume in breast cancer bearing mice. Forty female BALB/c mice [4 to 5 week years old, average 17 g weight] were randomly assigned into four groups: 1] exercise-tumor-exercise [ETE], 2] exercise-tumor-rest [ETR], 3] rest-tumor-exercise [RTE] and 4] rest-tumor-rest [RTR]. For tumorigenesis, MC4-L2 cell lines were used. Endurance training was performed for 8 weeks before inducing tumor in which training was initiated with 50% VO2max and reached 75% VO2max in the 8th week. Endurance training was performed with the intensity of 50 to 65% VO2max for 6 weeks after tumor induction. After training, serum IL-8 concentration was measured by ELISA. Data were analyzed by one-way ANOVA and Pearson correlation. There were significant differences in serum IL-8 concentration and tumor volume among the groups [P=0.0001]. Significant differences were between training groups after tumor induction with other groups. In addition, significant correlations were observed between serum IL-8 concentration and tumor volume among the groups [P>0.05]. Endurance training with moderate intensity reduces tumor volume. IL-8 is involved in angiogenesis and tumor growth and the decreased level of IL-8 is one reason for the reduced tumor volume. Due to reduction of the level of this cytokine in groups doing exercise after malignancy, endurance training in addition to a prophylactic role is presumed to have adjuvant therapeutic effects on estrogen-receptor dependent tumors