Figure 3: β-gal staining with X-Gal substrate in soleus muscle. Four groups (each consisted of 3 rats) of the normal Lewis rats treated with the hydrodynamic femoral intravenous injection of saline or 200 μg naked β-gal plasmid, Ch-β-gal plasmid DNA, and Ch-Fa-β-gal plasmid DNA, respectively. Soleus muscle were isolated and visualized for β-gal gene expression with X-gal substrate incubation 3 days post injection. (a) Shows the scanned images from the rat soleus muscles. (1) nontreated controls, (2) naked plasmid β-gal DNA injected, (3) Ch-plasmid β-gal DNA nanoparticles injected, and (4) the Ch-Fa-plasmid β-gal DNA nanoparticles injected rats. (b) Shows soleus muscle histological cross-sectional patterns of β-galactosidase protein expression stained with its corresponding antibody after hydrodynamic Ch-Fa- plasmid β-gal DNA injection (dark brown staining).