Accelerated Autophagy of Cecal Ligation and Puncture-Induced Myocardial Dysfunction and Its Correlation with Mammalian Target of Rapamycin Pathway in Rats

Figure 1. Cardiomyopathy and cardiac dysfunction in CLP rats. Representative hematoxylin and eosin staining of left ventricle sections (a). Cardiac functions examined by echocardiography, representative echocardiographic recordings from the two groups, LVEF and FS were measured (b). Original magnification, ×200; mean ± standard deviation, six rats per group, *P < 0.05; †P < 0.01. SHAM: Sham operated; CLP: Cecal ligation and puncture; LVEF: Left ventricle ejection fraction; FS: Fraction shortening.

Figure 2. The expression of LC3II and p62 in left ventricle. The protein levels of LC3II and p62 were quantified by Western blotting in the methods (a and c). Left ventricle sections stained with an anti-LC3 antibody (b). Original magnification: ×200. Bar, 100 μm. Mean ± standard deviation, six rats per group, *P < 0.05.

Figure 3. Ultrastructural features of autophagic vacuoles in the left ventricle harvested 18 h after CLP. Myocardium was normal in appearance with proper mitochondria distribution in sham-operated rats (a); myofibrillar disarray can be seen in CLP rats (b); there were more larger autophagosomes and more autolysosomes in CLP rats (c and d). The autophagosome appears as a double-membrane vesicle (arrows in [a and c]), the autolysosome is a single-membrane structure containing cytoplasmic materials at various stages of degradation (asterisks in [d]). Mitochondria (m) can be seen throughout the cytoplasm (×10,000). CLP: Cecal ligation and puncture.

Figure 4. The expression of p-mTOR (a) and PS6K1 (b) in left ventricle, left ventricle was harvested 18 h after CLP, and the protein levels of p-mTOR and PS6K1 were quantified by Western blotting in the methods. Mean ± standard deviation, six rats per group, *P < 0.05; †P < 0.01. p-mTOR: Phosphorylation of mammalian target of rapamycin; CLP: Cecal ligation and puncture; PS6K1: Phosphorylation of S6 kinase-1.

Figure 5. Correlation between p-mTOR, PS6K1, LC3II, p62. (a) mTOR and LC3II (n = 12, p-mTOR in the myocardium was not correlated with LC3II). (b) mTOR and p62 (n = 12, r = 0.66). (c) PS6K1 and LC3II (n = 12, r = −0.71). (d) PS6K1 and p62 (n = 12, r = 0.70). mTOR: Mammalian target of rapamycin; p-mTOR: Phosphorylation of mTOR; LC3II: Light chain 3 type II; PS6K1: Phosphorylation of S6 kinase-1.