Resistance exercise modulates lipid plasma profile and cytokine content in the adipose tissue of tumour-bearing rats

Cancer cachexia is a multifactorial syndrome characterised by progressive weight loss, frequently accompanied by anorexia, sarcopenia, and chronic systemic inflammation. The white adipose tissue is markedly affected by cachexia and contributes to this syndrome throught the secretion of pro-inflammatory factors which reach the adjacent tissues and the circulation. A nonpharmacologic intervention that may attenuate cancer cachexia is chronic physical activity, but the effect of resistance training upon adipose tissue inflammation in cachexia has never been examined. For that purpose we designed a protocol in which animals were randomly assigned to a control group (CT, n=7), a Tumour bearing group (TB, n=7), a Resistance Trained group (RT, n=7) and a Resistance Trained tumour bearing group (RTTB, n=7). Trained rats climbed a vertical ladder with an extra load attached to the tail, representing 75–90% of total body mass, 3 times per week, for 8weeks. In the 6thweek of resistance training, tumour cells (3×10⁷ Walker 256 carcinosarcoma) were inoculated in the tumour groups. Body, adipose tissue, muscle and tumour mass was determined, as well a blood biochemical parameters, and the hormone and cytokine profile assessed. The glycogen content of the liver and muscle was measured. IL-10, IL-6 and TNF-α protein expression was evaluated in the mesenteric adipose tissue (MEAT) examined. Resistance training increased by 9% body weight gain in RTTB (final weight 310.8±9.8g), when compared with TB (final weight 288.3±4.9g). LDL-c levels were decreased in RTTB (0.28±0.9mmol/L) by 43% when compared with TB (0.57±0.1mmol/L). HDL-c levels were increased in RTTB (1.31±0.12mmol/L) by 15% in regard to CT (1.13±0.7mmol/L) and 22% as compared with TB (1.07±0.07mmol/L). RTTB testosterone levels (577±131ng/mL) were 55% higher when compared with CT (254±41.3ng/mL) and 63% higher when compared with TB (221±23.1ng/mL). Adiponectin levels were augmented in RT (23μg/mL) by 43% when compared with TB (11μg/mL). Protein expression of IL-6 was increased 38% in TB MEAT (5.95pg/μg), as compared with CT (3.64pg/μg) and 50% compared with RTTB (2.91pg/μg). Similar results with respect to TNF-α TB (7.18pg/μg) were observed: 39% and 46%, higher protein expression in comparison with CT (4.63pg/μg) and RTTB (3.8pg/μg), respectively. IL-10 protein expression was found to be increased in TB (4.4pg/μg) and RTTB (3.2pg/μg) 50% and 47%, respectively, in comparison with CT (1.2pu/μg). The IL-10/TNF-α ratio was higher in RTTB in relation to all others experimental groups. The results show a robust effect of resistance exercise training in preventing important symptoms of cancer cachexia, thus strongly suggesting it may appear as an alternative to endurance exercise as a non-pharmacological therapy in the management of this syndrome.