Research Paper Volume 14, Issue 24 pp 9860—9876

Figure 4. C-C chemokine receptor 2 (CCR2) is the major receptor for C-C motif chemokine ligand 2 (CCL2) in muscle cells. Mouse C2C12 myoblasts (MBs) were differentiated into myotubes (MTs) with 2% horse serum for the indicated number of days. (A) Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and western blot analyses were performed to determine the expression of CCR2 in C2C12 cells cultured with 2% horse serum for the specified number of days. (B) Mouse C2C12 MBs were differentiated into MTs with 2% horse serum in the presence or absence of recombinant CCL2 and/or CCR2 inhibitor for three days. qRT-PCR results for CCR2, MyoD, MyoG, and myosin heavy chain (MyHC) in C2C12 cells. (C) Western blots of CCR2, MyHC, and myogenin in C2C12 cells cultured with 2% horse serum in the presence or absence of recombinant CCL2 and/or CCR2 inhibitor for three days. (D) MTs were stained with anti-MyHC antibody, and the nuclei were counterstained with 4, 6-diamidino-2-phenyindole (DAPI). Scale bars, 100 μm. (E) Quantitative results per field are presented. Number of experiments (No.) of (A–C) = 4 times, respectively. No. of (D, E) = 6 times, respectively. Data are expressed as mean ± standard deviation (SD). (A) *P<0.05, **P<0.005, ***P<0.0005, †P<0.01, ††P<0.001, †††P<0.0001 vs. MB. (B, C) *P<0.05, **P<0.005, ***P<0.0005, †P<0.01, ††P<0.001, †††P<0.0001 vs. siRNA Control MB, or vs. siRNA Control MT or siRNA Control MT & CCL2 (represented with lines). (E) *P<0.05, **P<0.005, ***P<0.0005, †P<0.01, ††P<0.001, †††P<0.0001 vs. siRNA Control MT, or vs. siRNA Control MT & CCL2 (represented with lines).