Fig. 1

Intramuscular transduction efficiency and inflammatory responses by AAV6 and AAV9 serotypes. Identical dose of AAV6 or AAV9 particles (2 × 10¹⁰ gc) or AAV9 particles (2 × 10¹¹ gc) and PBS control were injected into TA muscles. a Images of living mice show GFP in TA muscles 4 weeks post-injection. b GFP mean fluorescent intensity in TA muscles (N = 5). c GFP mRNA expression in the injected TA muscles (N = 5). CT values are normalized to Hprt and Gapdh housekeeping genes and to PBS-injected muscles. d Muscle histology of GFP expression in cross sections. Upper row shows bright field and DAPI staining of the nuclei. Images in the lower row were taken with a GFP filter and DAPI. Scale bar is 50 μm. e Muscle histology of HE staining. White arrows point to area with macrophage infiltration, and black arrows show myofibers with central nucleation. Scale bar is 200 μm. f Inflammatory gene expression in the AAV6- or AAV9-injected muscles (2 × 10¹¹ gc) (N = 4). CT values are normalized to Hprt and Gapdh housekeeping genes and to PBS-injected muscles. All eight genes are significantly up-regulated in AAV6 muscles, but only IL6 is up-regulated in AAV9. g Bar chart shows the proportion of myofibers with central nuclei. The total number of fibers is indicated above each bar