Background Sepsis is usually accompanied by cardiomyocyte apoptosis and myocardial depression. Protein kinase C (PKC) has been reported to be important in regulating cardiac function and apoptosis; however, which PKC isoform is involved in sepsis-induced myocardial apoptosis remains unknown. Materials and methods A rat model of sepsis by cecal ligation and puncture was used. Early and late sepsis refers to those rats sacrificed at 9 and 18 h after cecal ligation and puncture, respectively. Ventricular septum (Sep), left ventricle (LV), and right ventricle were fractionated into membrane, mitochondrial, and cytosolic fractions, individually. The protein levels of PKC isoforms (-α, -β, -δ, -e, -ζ, -ι, -λ, and -μ) and mitochondrial translocation of Bad were quantified by Western blot analysis. Apoptosis was detected by terminal deoxynucleotidyl transferase–mediated dUTP in situ nick-end labeling. The morphology of mitochondria was examined by electron microscopy. Results The membrane/cytosol ratio of PKCe was predominantly higher in the Sep, LV, and right ventricle under physiological conditions. At early sepsis, the membrane/cytosol ratio of PKCe was significantly decreased in Sep and LV. At late sepsis, cardiomyocyte apoptosis associated with severe mitochondrial swelling and crista derangement were observed in Sep and LV at late sepsis. Additionally, mitochondria/cytosol ratio of Bad was significantly increased in Sep and LV. Conclusions The early inactivation of PKCe in the ventricle may affect the mitochondrial translocation of Bad and subsequent mitochondrial disruption and apoptosis at late sepsis. This finding opens up the prospect for a potential therapeutic strategy targeting PKCe activation to prevent myocardial depression in septic patients.
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