| Objective: To study the characteristics of myocardial injury caused by Klebsiella pneumoniae pneumonia in aged rats, and to dicuss the molecular mechanism of pneumonia myocardial injury in elderly, and further for Dusuqing's mechanisms of protecting heart injury in aged pneumonia by the changes of interleukin(IL)-1, interleukin(IL)-6, TNF(tumor necrosis factor) -αand JAK/STAT pathway associated proteins and genes, such as JAK2, STAT1, STAT3, STAT5, JAK2mRNA and suppressor of cytokine signaling (SOCS)3 mRNA.Methods: The model of rats with Klebsiella pneumoniae pneumonia were duplicated through the tracheal intubation, also a model of myocardial injury caused by Klebsiella pneumoniae pneumonia.1 Experiment One Male SD rats, 5-6 months, were randomly divided into young control group (YCG) and young model group(YMG); the elderly were randomly divided into aged control group (ACG) and aged model group(AMG). The model were duplicated after given gastric tube feeding with the same volume of normal physiological saline (3ml·d-1) once a day for 3 days, and which would stop till the day sampling operation, 48h after model. 0.5h before making model, 24h and 48h after model, we observed the count of leukocyte and neutrophil percentage in peripheral blood. It was observed that the LDH, CK, CK-MB and blood-gas analysis in arterial blood; and the pathological change of lung tissue and cardiac muscle, and that in myocardial tissue ultrastructure, made bronchoalveolar lavage fluid for a culture for species identification.2 Experiment Two Male SD rats, were randomly divided into six groups: Lomefloxacin group (LG), Dusuqing group(DG), Rapamycin(RPM) group(RG), RPM and Dusuqing group(RDG), AG490 group(AG), and AG490 and Dusuqing group(ADG). 10 rats each group. Each group were perfused through mouth to stomach respectively with Lomefloxacin (40mg·kg-1·d-1, LG), Dusuqing (5.7g·kg-1·d-1, DG, RDG and ADG), RPM (0.4mg·kg-1·d-1, RG and RDG) once a day 3 days before model duplication; and AG490 (8mg·kg-1, AG and ADG) was injected subcutan- eously once half an hour before model duplication. The dose is conversed to dose equivalent in accordance with animal body shape coefficient. Sampling operation and treatment was the same to Experiment One.Results: Identification of the genus in bronchoalveolar lavage fluid culture of the rats All identified as Klebsiella pneumoniae.1 Experimental One Model building of myocardial injury induced by Klebsiella pneumoniae pneumonia in rats and the influence of aging1.1 Changes of leukocyte counts and neutrophil ratios in peripheral blood in each groupCompared to ACG and YCG seperately, neutrophil rates and the counts in peripheral blood increased significantly in AMG and YMG on the both time points(P<0.01). And the increased levels of the leukocyte counts and ratios is lower in AMG on the two points.1.2 Changes of pathological injury in the lungs and myocardium and the myocardial enzyme in each groupCompared to YCG and ACG respectively, the pathological injury of the lungs and myocardium were observed obviously in YMG and AMG, and also the ultrastructure of myocardial cells, the levels of LDH, CK and CK-MB significantly increased(P<0.01, P<0.05), and also the water content of the lungs and the heart inAMG and that of lungs in YMG(P<0.05, P<0.01). Compared to YMG, the levels of LDH, CK, CK-MB and the cardiac moisture increased significantly in AMG(P<0.05).1.3 Changes of PaO2 and PaCO2 in arterial blood in each groupCompared to YCG and ACG respectively, the levels of PaO2 in arterial blood decreased significantly(P<0.01), and that of PaCO2 increased(P<0.05) in both YMG and AMG. Compared to YMG , the levels of PaCO2 increased significantly(P<0.05), and that of PaO2 decreased(P<0.05) in AMG.2 Experiment Two Changes of JAK/STAT signaling in myocardial injury mediated by Klebsiella pneumoniae pneumonia in aged rats and the protective effect of Dusuqing Granule2.1 Changes of leukocyte counts and neutrophil ratios in the peripheral blood in each groupAfer being treated, the leukocyte counts and the neutrophil ratios dropped sharply in the treated groups(P<0.05, P<0.01) on the two points. But there were no significant difference between the treated groups, only more decreasing trend in RDG and ADG.2.2 Changes of the lungs and the myocardial pathological injury and the myocardial enzyme in each groupCompared with AMG, the pathology injury of lungs and the cardiac tissue had reduced significantly in the drug-treated groups, and LDH, CK and CK-MB were also significantly lower(P<0.05, P<0.01). The water content of the myocardial tissue decreased significantly in all of the treated groups(P<0.05, P<0.01), as well as the lung decreased significantly in DG,RG and AG. Compared to LG, the levels of CK-MB were significantly lower (P<0.01)in DG, RG, AG, RDG and ADG, CK decreased in ADG (P<0.05, P<0.01).2.3 Changes of PaO2 and PaCO2 in arterial blood in each groupCompared with AMG, PaO2 increased significantly in DG, while PaCO2 decreased in DG(P<0.05) and LG(P<0.05). Compared to LG, the levels of PaO2 trended to increase in DG(P> 0.05). PaCO2 in DG, AG and ADG is quite lower than that in LG(P<0.05,P<0.01), PaO2 in RDG is lower than DG(P<0.01).2.4 Changes of the expressions of cytokines in myocardial tissue of the rats in each groupCompared to ACG, the expressions and the counts of the positive cells of IL-1, IL-6 and TNF-αincreased significantly(P<0.01) in AMG. Compared to AMG, the expression and/or the positive cells of IL-6 and TNF-αreduced in LG, DG, RG, RDG, AG and ADG(P<0.01), and that of IL-1 ruduced in RG, RDG, AG and ADG(P<0.01). Compared to LG, the expressions and/or the counts of the positive cells of IL-1 and TNF-αreduced significantly in RG, RDG, AG and ADG(P<0.01), the counts of the positive cells of IL-6 increased(P<0.01) in RDG, while the expressions decreased in DG(P<0.01). Compared to DG, the positive-cell-counts of IL-1 decreased significantly in ADG(P<0.01), and that of IL-6 decreased obviously in RDG(P<0.01), while both of the two of TNF-αdecreased significantly in ADG(P<0.01). Compared to RG, the counts of the positive cells of TNF-αdecreased significantly in RDG(P<0.05). Compared to AG, the expression of the protein and the counts of the positive cells of TNF-αdecreased significantly in ADG(P<0.01).2.5 Changes of expressions of JAK/STAT pathway associated protein in myocardial tissue of the rats in each groupCompared with ACG, the protein expression and the counts of the positive cells of JAK2-p, p-STAT1, p-STAT3 and p-STAT5 increased significantly(P<0.01). Compared with AMG, all of the four targets'expressions were significantly decreased in the drug-treated groups (P<0.01), while the counts of the positive cells of p-STAT1 and p-STAT3 also decreased significantly in those groups(P<0.01), as well as the counts of JAK2 decreased significantly in AG, RDG and ADG(P<0.01), and that of STAT5 decreased significantly in the drug-treated groups with an exception of LG(P<0.01, P>0.05). Compared to LG, the protein expression of p-JAK2, p-STAT3 and p-STAT5 in DG and RG, the counts of the positive cells of p-STAT1 in DG, and the expression and the counts of cells of p-STAT1 in RG decresed significantly(P<0.01), the expression and the cell-count of p-JAK2, p-STAT1 and p-STAT3 were reduced in RDG, AG and ADG(P<0.01), and the expession of p-STAT5 were reduced significantly in AG and ADG(P<0.01). Compared with DG, the protein expression of p-JAK2, p-STAT1 and p-STAT3 were reduced significantly in RG, RDG and ADG, as well as the cell-count of p-STAT1 in those groups(P<0.01), and the expression of p-STAT3 in RG(P<0.01), and the protein expression of p-JAK2, p-STAT3 and the cell-counts of p-STAT1 and p-STAT5 in AG(P<0.01 , P<0.05), but the expression of p-STAT5 was increased significantly in RG and RDG(P<0.01). Compared to RG and AG respectively, the phosphorylation of STAT3 were reduced in RDG and ADG(P<0.01), and the expression of p-STAT5 were significantly increased in RDG(P<0.01), while decreased in ADG(P<0.01). 2.6 Changes of expressions of JAK2mRNA and SOCS3mRNA in myocardial tissue of the rats in each groupCompared with ACG, the expression of JAK2mRNA and SOCS3mRNA were significantly increased in AMG(P<0.01). Compared with AMG, the expression of JAK2mRNA were significantly decreased in DG, RG, RDG, AG and ADG(P<0.05, P<0.01), while SOCS3mRNA increased in each treated group at different levels, but only increased significantly in ADG(P<0.01). And at the same time, the level is higher than the others(P<0.01). The level between the drug-treated groups hadnot statistically significant in JAK2 mRNA(P>0.05).Conclusions:①Based on an existing pneumonia model duplicated through tracheal intubation, the model of myocardial injury induced by the Klebsiella pneumoniae pneumonia in rats was successly set up. The extent of myocardial injury in aged rats is more serious than that in young, and this may be related to aging.②Disorders of IL-1, IL-6, TNF-αand JAK/STAT signaling are involved in the occurrence and the development of myocardial injury induced by pneumonia, inhibition of the expression and activation of these factors can reduce the extent of myocardial injury.③Dusuqing has significant protective effects against myocardial injury caused by pneumonia in elderly, and its main mechanisms may be related to reduce the expressions of cytokines, regulate and control JAK/STAT signaling activation and SOCS3mRNA expression.④JAK/STAT-blocking agents and Dusuqing can significantly reduce myocardial injury, and the effect of Dusuqing cooperating with blockers on myocardial protection is more obvious. Dusuqing can not only reduce inflammatory cytokines and lower JAK/STAT activation, but also there may be other ways of its mechanism to be further explored.
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