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ObjectiveTo explore the therapeutic effect and mechanism of Guipitang on rats with myocardial ischemia. MethodFifty SD rats were divided into five groups： a control group， a model group， low and high-dose Guipitang （7.52， 15.04 g·kg-1） groups， and a trimetazidine group （0.002 g·kg-1）. By intragastric administration of vitamin D3 and feeding rats with high-fat forage and injecting isoproterenol， the rat model of myocardial ischemia was established. After drug treatment of 15 d， an electrocardiogram （ECG） was performed to analyze the degree of myocardial injury. A fully automatic biochemical analyzer was used to detect the changes in the serum levels of total cholesterol （TC）， high-density lipoprotein cholesterol （HDL-C）， triglyceride （TG）， and low-density lipoprotein cholesterol （LDL-C）. Hematoxylin-eosin （HE） staining and Masson staining were used to observe myocardial histopathological changes. TdT-mediated dUTP nick end labeling （TUNEL） staining was used to detect cardiomyocyte apoptosis. Western blot was adopted to detect the protein levels of extracellular signal-regulated kinase 1/2 （ERK1/2）， phospho-ERK1/2 （p-ERK1/2）， p38 mitogen-activated protein kinase （p38 MAPK）， phospho-p38 MAPK （p-p38 MAPK）， B-cell lymphoma-2 （Bcl-2）-associated X （Bax）， Bcl-2， and cleaved cysteine aspartate proteolytic enzyme （cleaved Caspase-3）. ResultCompared with the control group， the ECG S-T segment decreased in the model group. The serum levels of TC， TG， and LDL-C were increased significantly （P<0.05）. The arrangement of myocardial tissue was disordered， and the proportion of cardiomyocyte apoptosis increased. The protein levels of cleaved Caspase-3， Bax， and p-p38 MAPK in the heart were increased， and the Bcl-2 expression was decreased （P<0.05）. Compared with the model group， the S-T segment downward shift was restored in the low and high-dose Guipitang groups and trimetazidine group， and the levels of TC， TG， and LDL-C were decreased. The protein expression of cleaved Caspase-3 and Bax in the heart dropped， and p-p38 MAPK and p-ERK1/2 protein expressions increased significantly （P<0.05）. The degree of myocardial injury was alleviated， and the proportion of cardiomyocyte apoptosis decreased. Bcl-2 protein expression was increased significantly in the low-dose Guipitang group （P<0.05）. ERK1/2 and p38 MAPK proteins had no significant difference among different groups. ConclusionGuipitang could alleviate myocardial injury and inhibit cardiomyocyte apoptosis in rats by activating the expression of ERK1/2 and p38 MAPK.
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Objective To evaluate the effect of hypotension factor on endotracheal tube cuff-in-duced damage to tracheal mucous membrane of rabbits. Methods Eighty healthy rabbits of both sexes, aged 3.0-3.5 months, weighing 2.5-3.5 kg, were divided into 16 groups(n=5 each)according to the cuff pressure and mean arterial pressure(MAP): different cuff pressures when MAP did not decrease groups(C1M1group, C2M1group, C3M1group, C4M1group), different cuff pressures when MAP de-creased by 20% of the baseline value groups(C1M2group, C2M2group, C3M2group, C4M2group), dif-ferent cuff pressures when MAP decreased by 30% of the baseline value groups(C1M3group, C2M3group, C3M3group, C4M3group), and different cuff pressures when MAP decreased by 40% of the baseline value groups(C1M4group, C2M4group, C3M4group, C4M4group). Different cuff pressures were 0, 10, 20 and 30 cmH2O.At 2 h of tracheal intubation, the tracheas in the cuff-compressed area were harvested and sliced for examination of the pathological changes of tracheal mucous membrane after haematoxylin and eosin staining(with a light microscope), and the damage to tracheal mucous membrane was scored. Results When at the same low pressure(MAP decreased by 20%, 30% and 40% of the baseline value), the score of damage to tracheal mucous membrane increased with the increasing cuff pressures(P<0.05). When at the same cuff pressure(10, 20 and 30 cmH2O), the score of damage to tracheal mucous membrane in-creased with the increasing MAP(P<0.05). There was interaction between cuff pressure and MAP, F=2.034(P<0.05). Conclusion There is interaction between the effects of hypotension factor and endotra-cheal tube cuff factor on damage to tracheal mucous membrane; hypotension factor can aggravate endotra-cheal tube cuff-induced damage to tracheal mucous membrane of rabbits.