The changes of myocardial tissue injury. LDH (A) and CK (B) activities were detected in the coronary effluent liqud. Data are means ± S.E.M. of 8 determinations. * p < 0.05 vs. control group; # p < 0.05 vs. I/R group; & p < 0.05 vs. PC group; $ p < 0.05 vs. I/R + NaHS group. § p < 0.05 vs. PC + NaHS group. (C). Ultrastructural changes in cardiomyocytes (magnification × 10000). Mitochondria structure was intact with well-organized myofilaments in the control group. Severe cell damage, including nuclear pycnosis, nuclear chromatin margination, aggregation and condensation, and swelling of mitochondria, and disruption of myofibrils were observed in the I/R and PC groups. Compared with I/R group, cardiomyocytes injury was lightened in the I/R + NaHS group.The cardiomyocytes injury was further lightened in the PC + NaHS group in comparison with the I/R + NaHS group. LY294002 canceled the effect of NaHS on the cardiomyocytes injury but NAC enhanced this effect of NaHS. (D). A infarct size measured using TTC staining. Data were from four independent experiments. # p < 0.05 vs. I/R group; & p < 0.05 vs. PC group; $ p < 0.05 vs. I/R + NaHS group; § p < 0.05 vs. PC + NaHS group.