Quercetin Protects against Obesity-Induced Skeletal Muscle Inflammation and Atrophy

Figure 3

Quercetin suppresses inflammatory responses in cocultured myotubes and macrophages treated with FFA. C2C12 myotubes (Mb) were cocultured with Raw264.7 macrophages (M⌀) for 24 h (Co) and then treated with 500 μM palmitic acid for the next 24 h (Co/FFA). As the control, the same numbers of Mb and M⌀ were cultured separately and mixed after being collected/harvested, named as mixture (Mix), same as FFA treated condition, which was named as Mix/FFA. The established Mb and M⌀ were pretreated with 50 μM quercetin in serum-free DMEM for 1 h (Co/FFA/Q). ((a), (c)) qRT-PCR analysis of transcripts of inflammatory cytokines (TNFα and MCP-1) and inflammatory receptors (4-1BB and TLR4). (b) Protein levels of TNFα and MCP-1 released into the culture medium were measured by ELISA. (d) Phosphorylated ERK, ERK, phosphorylated p38 MAPK, p38 MAPK, IκBα, and α-tubulin were determined by Western blotting. (e) The intensities of the bands were measured using ImageJ. Data are means ± SEM of three independent triplicate experiments. , , and for the differences between the Co/FFA group and the Mix, Mix/FFA, or Co groups. and for the differences between the Co/FFA/Q and Co/FFA groups.

(a)

(b)

(c)

(d)

(e)