Mice received a single administration (first group), two administrations (second group), or three administrations (third group) of DOXO (2 mg/kg and 10 mg/kg; i.p.) and Cx43 and pCx43 expressions were detected by Western blot analysis into tissue homogenates from mice; GAPDH protein expression was used as loading control (A,B); Effects of DOXO on mCx43 (C) and mpCx43 (D) expression were detected by Western blot analysis on mitochondrial protein lysate from mice; TOM20 protein expression was used as loading control. Values were expressed as mean ± S.E.M. from at least three independent experiments each performed in duplicate. Values are expressed as mean ± S.E.M. from at least three independent experiments each performed in duplicate. Data were analyzed by Student’s t-test. * p < 0.05, ** p < 0.005 and *** p < 0.001 versus control. Representative Western blots of Na+/K+ ATPase and Ox-Phos Complex II were used as markers of sarcolemma (SF) and mitochondria (MF), respectively, to demonstrate the purity of the mitochondrial extracts (E).