Exercise and Shark Liver Oil Supplementation Reduce Tumor Growth and Cancer Cachexia in Walker 256 Tumor Bearing Rats

Abstract

This study investigated whether exercise associated to shark liver oil supplementation (1 g/kg b.w./day) affects tumor growth, cachexia, lipid peroxidation and proteins expression involved in cell death in Walker 256 tumorbearing rats. Animals were divided into 4 groups: sedentary tumor-bearing (W), sedentary tumor-bearing shark liver oil supplemented (WSL), exercised tumor-bearing (EW) and exercised tumor-bearing shark liver oil supplemented (EWSL). Training sessions consisted of 6 bouts, 30 seconds each with 50% body-weight load attached to the trunk followed by 1 minute of resting (jump training). Five minutes after the finish jump training the exercise groups were subjected to 30 minutes of continuous swimming with a load equivalent to 6% of body weight, 4 times a week during 8 weeks. Tumor cells were injected at the 6 th training week and all groups were killed 15 days post inoculation. Tumor weight (g) in W group was of 26.50 ± 1.79 and in the WSL, EW and EWSL was of 14.08 ± 0.91, 15.60 ± 0.55 and 12.60 ± 1.07, respectively. The group W showed hypoglycemia (68.67 ± 2.12 mg/dl), hyperlactacidemia (1.49 ± 0.06 mmol/L), hypertriacylglycerolemia (161.4 ± 9.4 mg/dl) and body weight reduction (13.21 ± 2.25 g) characterizing cachexia state. The groups WSL, EW and EWSL presented reduction of tumor cells proliferation ex vivo, and the production of hydroperoxide and apoptosis was increased. Bax/Bcl-2 expression ratio was increased only in the exercised groups. Shark liver oil supplementation and exercise alone were able in to avoid the installation of cachexia state and also reduced tumor growth, but the association of both cause further effect only in the tumor growth.