Kleiton Augusto Santos Silva, Ralmony de Alcântara Santos, Marcelo Rocino Arlotti, Luciana Jorge, Rafael da Silva Luiz, Rodolfo Rosseto Rampaso, Tatiana Sousa Cunha, and Nestor Schor
A type of exercise (Resistance Exercise Training – RET) that is markedly applied to increase muscle mass has been prescribed to prevent muscle atrophy from catabolic conditions such as, diabetes and chronic kidney disease. However, how this type of exercise modulates renal system remains unclear. It prompted us to apply progressive RET to STZ-induced diabetes rats in order to investigate renal environment. Progressive RET was applied to Wistar rats under following exercise program: 6 to 12 climbs/day, 5 days/week, 8 weeks, at 50 to 80% of maximal loading test. After streptozotocin injection, animals were divided into four groups: two control groups (non-exercised and exercised) and two diabetic groups (non-exercised and exercised) with 4 to 6 rats/group. Kidney weight (KW), muscle weight, proteinuria and protein level (assessed by Western blot and multiplex technology) were determined. It was found that RET did not protect exercised diabetic animals from loss of muscle mass. RET did not influence the performance in maximal loading test in diabetic groups (p>0.05); additionally exercised diabetic animals did not recover body weight (p>0.05). KW was preserved in exercised diabetic animals meanwhile proteinuria was lowering as well (15.83 ± 2.6 mg/24h) when compared to diabetic group (37.66 ± 3.2 mg/24h, p<0.05). We assessed upstream and downstream of mTOR and found significant decreases in PI3K, p-Akt and p-4EBP1 in kidneys of exercised diabetic animals (p<0.05). Moreover, we observed that kidney protein level of TGFβ-1 was markedly decreased in exercised diabetic animals. Under progressive RET program, kidneys may be functionally protected and mTOR-signaling pathway plays important role on renal environment. However, skeletal muscle showed no improvement under this program, suggesting different mTOR modulation among renal and muscle functions
