In vitro and in vivo observations of gallic acid in alleviating myocardial injury induced by hypobaric hypoxia and the mechanism
Objective To observe the improvement effect of gallic acid(GA)on myocardial injury induced by hypo-baric hypoxia(HH)in vivo and in vitro and to explore its related mechanisms.Methods In this in vivo study,30 SD rats were randomly divided into five groups:the normal group(rats were fed without any intervention),the HH model group,and the low-,medium-,and high-dose GA groups.Except the normal group,the chronic altitude sickness models were established by exposure to HH cabin at an altitude of 5 000 m for 30 days in the other groups,and rats in the low-,medium-,and high-dose GA groups were given 12.5,25.0,and 50.0 mg/kg GA by gavage,respectively;rats in the nor-mal group and HH model group were given the same amount of normal saline.Right ventricular ejection time(RVET),right ventricular pre-ejection period(RPEP),ejection fraction(EF),and pulmonary artery pressure acceleration time(PAAT)were detected by echocardiography.Serum oxidative stress indexes such as malondialdehyde(MDA),superoxide dismutase(SOD),and glutathione catalase(GSH-Px)were measured by a biochemical kit.HE staining was used to ob-serve the pathological changes in myocardial tissues in rats.ELISA was used to detect the vascular endothelium functional indexes nitric oxide synthase(iNOS)and endothelin-1(ET-1)in the rat myocardial tissues.In the in vitro study,rat H9C2 cardiomyocytes were divided into the normal group,model group,and low-,medium-,and high-dose GA groups.H9C2 cardiomyocytes in the low-,medium-,and high-dose GA groups were treated with 0.075,0.100,and 0.125 μmol/L GA,respectively.The normal group was not treated,the other groups were cultured in 1%O2 environment mode for 24 h to establish the cell hypoxia injury models,Morphological changes in myocardial cells in rats were observed under an in-verted microscope.Cell viability was detected by the CCK-8 method.Apoptosis was detected using the AnnexinV-fluores-cein isothiocyanate(AnnexinV-FITC)/propidium iodide(PI)apoptosis detection kit.Dichloro-dihydro-fluorescein diace-tate(DCFH-DA)fluorescent probe staining was used to detect the level of reactive oxygen species(ROS)in rat cardiomyo-cytes.Western blotting was used to detect apoptosis-related proteins B lymphoblastomas 2(Bcl-2),Bcl-2-associated X protein(Bax),and Caspase-3 in rat cardiomyocytes.Results In the in vivo study,compared with the normal group,PAAT in the HH model group and the low-,medium-,and high-dose GA groups decreased,but the decrease in the HH model group was more obvious;RPEP increased,but it was more obvious in the HH model group(all P<0.05).There were no significant differences in EF or RVET between groups.Compared with the normal group,the levels of SOD and GSH-Px all decreased in the HH model group and the low-,medium-,and high-dose GA groups,but the HH model group decreased more obviously;MDA levels all increased,but the increase in the HH model group was more obvious(all P<0.05).In the normal group,the myocardial fibers were arranged neatly,the structure was normal,and there were fewer inflammatory cells and a small amount of red blood cell infiltration.In the HH model group,myocardial fibers were loosely arranged,inflammatory cells were infiltrated,and some myocardial cells were infiltrated with red blood cells.Compared with the HH model group,the pathological changes in the low-,medium-,and high-dose GA groups improved,and the im-provement was more obvious with the increase of drug doses.Compared with the normal group,the levels of ET-1 and iNOS in the HH model group and low-,medium-,and high-dose GA groups all increased,but the increase in the HH mod-el group was more significant(all P<0.05).In the in vitro study,the cells in the normal group were normal in morphology,were neatly arranged,and had clear cell boundaries.In the model group,the cells were in disorder,sparse,and drawn,and the cell gap was widened.Compared with the model group,the drawing situation caused by hypoxia in the low-,medi-um-,and high-dose GA groups was obviously improved,and the number of cells increased.Compared with the normal group,the apoptosis rate and ROS level of myocardial cells in the model group and the low-,medium-,and high-dose GA groups all increased,but the increase in the model group was more obvious(all P<0.05).Compared with the normal group,the expression levels of Caspase-3 and Bax protein in the model group increased,while the expression level of Bcl-2 protein decreased.Compared with the model group,the expression levels of Caspase-3 and Bax protein in the low-,medi-um-,and high-dose GA groups decreased,while the expression level of Bcl-2 protein increased(all P<0.05).Conclusion GA can alleviate myocardial injury in both in vivo and in vitro HH myocardial injury models,and its mecha-nism may be related to reducing oxidative stress,improving endothelial function,and reducing apoptosis.
万方数据
维普
