| ObjectAtherosclerosis(AS)is a pathological process in which excess cholesterol,triglyceride and other lipids are deposited in the walls of blood vessels,ultimately resulting in sclerosis,stenosis or occlusion of the middle and large arteries,regarded as a common pathological basis of coronary heart disease,stroke and other thrombotic diseases.Atherosclerosis is also an inflammatory disease and macrophages plays a key role in the development of AS.Secreted by macrophages and lymphocytes,lipoprotein-associated phospholipase A2(Lp-PLA2)has become a focus in recent years due to its specific pro-inflammatory effect in atherosclerosis.Aerobic exercise improves dyslipidemia,and prevents and delays the occurrence and development of AS,but its mechanism has not been fully clarified.Although there are a few studies about the effect of exercise on the levels of Lp-PLA2 in obesity,the limited research results suggest that Lp-PLA2 may play an important role in improving the disorders of glucose and lipid metabolism in obesity.Until now,there is still no report about the changes of Lp-PLA2 level in AS induced by exercise.On the basis of our previous research that decrease of serum Lp-PLA2 through aerobic exercise may be involved in the improvement of glycolipid metabolism in female obesity adolescents,the study detected the levels of Lp-PLA2 in serum and multiple tissues(including liver,gastrocnemius and fat)of AS model rats after 4-week moderate aerobic exercise for exploring the role of Lp-PLA2 in exercise-induced alleviation of AS and the improvement of glycolipid metabolism as well as the mechanisms,which will provide theoretical basis for the prevention and treatment of AS through aerobic exercise.MethodTwenty-seven SD rats aged 6 weeks were randomly divided into normal control group(Con,n=9)and AS model group(n=18),which were fed with common diet and high fat diet,respectively.The AS model rats were established by intraperitoneal injection of Vitamin D3 in combination with 8-week high fat diet feeding.For verifying the successful establishment of AS rats,one rat from Con group and two rats from AS model group were taken randomly to determine the levels of blood glucose and lipid as well as morphological and pathological alterations of the aorta.Sixteen AS model rats were randomly divided into AS group(n=8)and exercised AS group(EAS,n=8).EAS group rats did moderate intensity exercise on treadmill for 4 weeks while Con and AS rats kept sedentary life,with all of the rats were fed with common diet during the experiments.At 36 hours after the last exercise,the blood of the three group rats were drawn to measure the circulating levels of FBG(fasting blood glucose),FINS(fasting insulin),TC(triglyceride),TG(total cholesterol),LDL and HDL).The serum Lp-PLA2 were measured by ELISA.Then the rats were anaesthetized and sacrificed,and the liver,gastrocnemius and perirenal fat of the rats were collected to detect the protein levels of Lp-PLA2,and the full-length aorta of the rats were separated to determine AS arteriosclerosis plaque andthe infiltration of macrophages by ELISA.Results1.Compared with the Con rats,The serum Lp-PLA2(P<0.01)and protein levels of Lp-PLA2 in the liver,gastrocnemius(both P<0.05)and adipose tissue(P<0.01)of AS rats were significant increased,accompanied with disorders of glucose and lipid metabolism(increases of TC,TG,LDL and FINS as well as decrease of HDL,but unchanged FBG),appearances of atherosclerotic plaques and atherosclerotic pathological characteristic in aorta,and enhancement of macrophage infiltration in aorta(reflected by increase of macrophage-specific marker CD68).2.Four weeks of moderate intensity exercise decreased the serum Lp-PLA2(P<0.01)and protein levels of Lp-PLA2 in the liver(P<0.05),gastrocnemius and adipose tissue(both P<0.01)of AS rats,accompanied with improvement of glucose and lipid metabolism(decreases of the levels of TC,TG,LDL,but non-alteration of HDL),reduction of AS plaque,and alleviations of atherosclerotic pathological changes and macrophage infiltration in aorta.Conclusion1.The serum Lp-PLA2 and protein levels of Lp-PLA2 in the liver,gastrocnemius and adipose tissue of AS rats were significantly increased,which were decreased significantly by 4-week moderate intensity exercise.2.The decrease of the levels of Lp-PLA2 in the serum,liver,gastrocnemius and adipose tissue of AS rats by exercise may be related to reducing the severity of AS in aorta and improving the metabolism of glucose and lipid in AS rats.Furthermore,the reduced Lp-PLA2 may alleviate the severity of aortic atherosclerosis by reducing macrophage infiltration. |
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