Resistance Training Alters Cytokine Gene Expression in Skeletal Muscle of Adults with Type 2 Diabetes

Abstract

Resistance training results in muscle hypertrophy and improves glycemic control in patients with type 2 diabetes. Whether resistance training modulates inflammation in muscles of diabetic patients remains unknown. We examined the expression of genes encoding the cytokines, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-lβ) and transforming growth factor-β, (TGF-β,) as well as the pan-leukocyte marker CD18. Thirty men and women (67 ± 7 years) were randomized to either 16 weeks of resistance training and usual diabetes care (EX) or to usual diabetes care only (CON). Muscle biopsies were obtained from the vastus lateralis muscle prior to the 16-week intervention, and 72 h following the maximal strength test post-intervention. Fiber cross-sectional area (CSA) was determined following ATPase staining. Cytokine and CD18 transcript levels were assessed by real-time PCR. Resistance training increased CSA of type I and II fibers (both P < 0.05) and IL-1β transcript levels (P = 0.05). TNF-α (P < 0.05) and TGF-β₁ transcripts (P < 0.05) increased over time in the EX group, but these increases did not differ from those in the CON group. In both groups, the increase in CD18 transcripts remained minimal. The two groups differ by the relationship between changes in CD18 and changes in cytokine transcripts, suggesting that resistance training affects the source of cytokines in muscle. Our studies establish that resistance training in older adults with type 2 diabetes results in muscle fiber hypertrophy, despite a greater accumulation of inflammatory cytokine transcripts in muscle.