Figure 2

Peroxisome proliferator-activated receptor gamma coactivator (PGC)-1β ameliorates muscle damage in dystrophin-deficient (mdx) mice without induction of utrophin or other neuromuscular junction (NMJ) genes. (A) Five week old control (WT), mdx, mdx mice with overexpression of PGC-1α in muscle cells (mdx/MCK-PGC-1α), or mdx mice with overexpression of PGC-1β in muscle cells (mdx/MCK-PGC-1β) (n = 5 each group) were sacked, and quantitative PCR was performed on mRNA isolated from the gastrocnemius. Genes of the NMJ and genes involved in oxidative phosphorylation (Ox-Phos) were analyzed. (B) Quadriceps from mdx, mdx/MCK-PGC-1α and mdx/MCK-PGC-1β were harvested and subjected to immunoblot analysis with anti-utrophin antibody and anti-pan-actin antibody. Results are representative of three independent experiments. (C) Five-week-old WT, mdx, MCK-PGC-1α and MCK-PGC-1β mice were sacked and serum creatine kinase activity was measured. Bars depict average serum creatine kinase activity (n = 5). (D) Histological sections from gastrocnemius of 5-week-old WT, mdx, MCK-PGC-1α and MCK-PGC-1β mice were prepared and stained with hematoxylin and eosin. Black arrows indicate centralized nuclei. (E) Histological sections from gastrocnemius of 5-week-old WT, mdx, MCK-PGC-1α and MCK-PGC-1β mice were stained with anti-laminin (green) to show muscle fiber boundaries and 4',6-diamidino-2-phenylindole (DAPI) to stain nuclei (blue). Representative images shown (left), with red arrows indicating centralized nuclei. Bars (right) depict percentage of nuclei counted which were centralized (n = 5). (F) Images of the same section were analyzed for relative fiber size using ImageJ. Bar histograms represent size distribution of the muscle fibers (right). (G) Five-week-old WT, mdx, MCK-PGC-1α and MCK-PGC-1β mice were injected intraperitoneally with 1% v/w Evans Blue solution and sacrificed 16 hours later. Histological sections from gastrocnemius, quadriceps and tibialis anterior were analyzed for dye incorporation into muscle fibers by fluorescence microscopy. Representative images are presented. Error bars represent SEM. *P < 0.05. AChR, acetylcholine receptor.