| BackgroundMyocardial energy metabolism in healthy adults require ATP50%-70% from beta oxidation of long-chain fatty acids,obstacles in any link of uptake,transport and myocardial fatty acid utilization in the process,it will cause the morphology and function of myocardial pathological changes.Previous studies have found that severe anemia,poisoning,infection,obesity,metabolic syndrome,diabetes and chronic heart failure can cause myocardial cell steatosis,leading to myocardial lipid damage.But the impact of hyperlipidemia on cardiomyocytes is rarely studied.Myocardial steatosis often occurs in obesity,metabolic syndrome,diabetes and other metabolic diseases,but the relationship between hyperlipidemia and myocardial steatosis is rarely studied.To understand the relationship between the two can further study the metabolic characteristics of fatty acids in hyperlipidemia and its impact on cardiac function.ObjectiveTo investigate the effect of hyperlipidemia on the morphology and myocardial lipid metabolism of rat cardiomyocytes,and to provide experimental basis and theoretical reference for clinical treatment of hyperlipidemia.Methods1.To establish hyperlipidemia rat model by high fat diet.According to the time of sacrifice,they were divided into four groups,8 weeks group and 12 weeks group.2.The serum levels of total cholesterol(TC)triglyceride(TG)were measured at the end of the 4th week,the 8th week and the 12 th week.At the same time,the heart function was detected by two-dimensional ultrasound system.3.To observe the myocardial pathological changes of hyperlipidemia rats: oil red o staining and transmission electron microscopy showed that the myocardial cells in the lipid droplet content and distribution.4.Immunohistochemical staining,immunofluorescence staining and westernblotting were used to determine the content of H-FABP in myocardium of rats.Results1.The level of TG in rats of high-fat diet group was significantly higher than that of control group at the end of 4th week,8th week and 12 th week(p<0.05,p<0.01),but the level of TG in the experimental group did not change significantly at the end of the 4th week,the 8th week and the 12 th week(p> 0.05).The levels of TC in the experimental group were significantly higher than those in the control group at the end of the 4th week,the 8th week and the 12 th week(p<0.001).The rats in the experimental group at the end of the 4th week,(p<0.001,p<0.01)at the end of the 12 th week.2.Echocardiography showed that the Lvid: d,Lvpw: d of the rats in the high-fat diet group were significantly higher than those of the control group at the end of the 4th week,the 8th week and the 12 th week(p<0.05,p<0.001,p<0.01).The Lvid: d,Lvpw: d of the experimental group were significantly increased at the end of 4w,8w and 12 w.The LVEF of the experimental group was significantly lower than that of the control group(p<0.001,p<0.01)at the end of the 4th week,the 8th week and the 12 th week,(p<0.05),and decreased significantly at the end of the 12 th week(p<0.001).3.Distribution of myocardial lipid droplets in hyperlipidemia rats Myocardial red O staining showed that there was a large number of small lipid droplets in the myocardium after the rats were fasted for 12 hours in the experimental group at 4 weeks,which was widely distributed in myofibrils between.In the control group,there was almost no lipid droplet in the myocardium.The content of lipid droplets was the highest at the end of the4 th week,and decreased at the end of the 8th week and the 12 th week.The electron microscope showed that the lipid droplet accumulation in different size between membraneof cardiomyocytes and myofibrils.4.Immunofluorescence staining of H-FABP in hyperlipidemic ratsThe expression of H-FABP in myocardium of rats in experimental and control groups was mainly expressed in cytoplasm,Yellow particles.Compared with the control group,the expression of H-FABP increased at the end of 4w,8w and 12 w in the experimental group,the 12 th week increased most significantly.Immunofluorescence showed that H-FABP increased at the end of 4w,8w and 12 w,consistent with the results of immunohistochemistry.The expression of H-FABP in the myocardium of the experimental group was higher than that of the control group.The expression of H-FABP increased gradually with the time prolonged,but there was no obvious change in the control group.There was no significant difference between the 4w group and the control group(p> 0.05).Compared with the control group,the expression of 8w group,12 w group was significantly increased(p<0.001).ConclusionHyperlipidemia can lead to the occurrence of myocardial steatosis and has effect on the heart function,with the continuous increase of the concentration of serum lipid,the expression of H-FABP in the myocardium is gradually increased,and Steatosis was reduced. |
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