Confocal micrographs of POMC gene electroporation on endorphin expression in muscle. (A) Immunohistochemical detection of endorphin immunoreactivity in the negative control that omitted the primary antibody. A muscle nucleus is labelled by 4,6-diamidino-2-phenylindole (blue). (B) Overexpression of endorphin immunoreactivity (green) in the POMC-treated group. Scale bar, 40 μm. (C) High-magnification image (from (B)) of endorphin-positive puncta shows the detailed distribution of endorphin in a muscle cell. Scale bar, 20 μm. (D) Endorphin-positive puncta are absent from muscle electroporated with pCMV-Script vector alone. Scale bar, 20 μm. (E, F) No significant inflammatory cell infiltration or muscle damage on haematoxylin/eosin staining of POMC-electroporated muscle (E) and untreated muscle (F). Original magnification, ×200. Scale bar, 100 μm.