| ObjectionWe speculate that the nano-metal zinc particles in the air can aggravate the structural function remodeling of the heart in myocardial infarction,and establish a myocardial infarction model by using coronary artery ligation in mice.The model mice were subjected to respiratory control,and the effects of nano-metal zinc particles in the air on cardiac functional structure after myocardial infarction were analyzed by means of echocardiography,histopathology,immunofluorescence and enzyme-linked immunosorbent assay.Pollution provides a theoretical basis for the deterioration of ischemic heart disease.Methods 1.The experimental mice were divided into 3 groups according to randomization,15 in the control group,30 in the myocardial infarction group and 30 in the particulate matter group after myocardial infarction;2.The myocardial infarction model was established by coronary artery ligation in the myocardial infarction group and the particulate matter.The control group only underwent thoracotomy,and no coronary artery ligation was performed.Other operations were the same as myocardial infarction;3.The particulate matter of mice were placed in a specially designed breathing control box,and a solution containing ultrafine nano zinc particles was atomized into a breathing box using a nebulizer aerosol generator to perform a breath control experiment;4.After 8 weeks of respiratory control,small animal ultrasound system was used to detect cardiac function in each group,including left ventricular end-systolic diameter(LVEDS),left ventricular end-diastolic diameter(LVEDD),left ventricular end-systolic volume(LVEVS),left ventricular end-diastolic volume(LVEVD),stroke volume(SV),ejection fraction(EF),fraction shortening(FS),left ventricular anterior wall systolic thickness at end-systolic(LVAWS),left ventricular anterior wall diastolic thickness at end-diastolic(LVAWD),left ventricular posterior wall contraction Period thickness at end-systolic(LVPWS),left ventricular posterior wall diastolic thickness at end-diastolic(LVPWD)and heart rate(HR);5.The Masson trichrome method was used to detect the changes of myocardial collagen content in infarcted area,and the condition of myocardial fibrosis was determined;6.Use immunofluorescence to detect the number of cardiomyocytes,morphological changes and cell proliferation rate;7.In situ end-transferase labeling(TUNEL)was used to detect the apoptosis of cardiomyocytes in each group;8.Detection of serum interleukin 11(IL-11),adrenaline(A),norepinephrine(NA),and dopamine(DA)levels by enzyme-linked immunosorbent assay(ELISA).Results 1.Mortality of mice: 60 mice were modeled,including 12 died of acute heart failure within 1 hour after surgery,5 died of infection or heart failure within 3 days after surgery,and 4 died during respiratory control experiment.The mortality rate of the sinus group was 30%,and the mortality rate of the inhalation group after myocardial infarction was 40%;2.Ultrasound detection in mice: After 8 weeks of respiratory control,the results showed that compared with the normal control group,LVEDS,LVEDD,LVEVS,and LVEVD in the myocardial infarction group were significantly increased(P<0.05),while EF,FS,Both were significantly reduced(P<0.05),the mouse ventricular dilatation,and decreased cardiac function.Compared with the myocardial infarction group,LVEDS,LVEDD,and LVEVS in the inhalation group were significantly increased(P<0.05),while SV,EF,FS,LVAWS,LVAWD,LVPWS,and LVPWD were significantly decreased(P<0.05),indicating that the infiltration of ultrafine particles in mice increased ventricular dilatation and decreased cardiac function;3.Masson trichrome staining: Compared with the control group,the myocardial infarction group and the particulate matter had significant collagen deposition(P<0.05).Compared with the myocardial infarction group,the collagen content the particulate matter was more obvious(P<0.05),it can be seen that inhalation of ultra-fine nano-zinc particles aggravates the deposition of collagen content after myocardial infarction,and at the same time exacerbates the ventricular remodeling of the left ventricle;4.Cell membrane staining results: Compared with the control group,the myocardial cells of the myocardial infarction group were significantly increased(P<0.05).Compared with the myocardial infarction group,the cardiomyocytes in the particulate matter were significantly increased(P<0.05).It indicates that the myocardial infarction cells continue to increase after inhaling ultrafine particles.At the same time,the cell size difference is large,the arrangement is disordered;5.Cell proliferation results: Compared with the control group,the PH3 positive rate was significantly higher in the myocardial infarction group and the particulate matter group,indicating that the number of myocardial proliferation was significantly reduced(P<0.05).However,compared with the myocardial infarction group,there was no significant difference in the positive expression of PH3 the particulate matter group(P>0.05),indicating that inhalation of ultrafine nano zinc particles did not inhibit the proliferation of myocardial cells in myocardial infarction;6.Cardiomyocyte apoptosis: Compared with the control group,the apoptosis of the myocardial infarction group and the particulate matter was significantly increased(P<0.05).Compared with the myocardial infarction group,the number of apoptosis in the infarcted area was significantly increased(P<0.05).It is indicated that inhalation of ultrafine nano zinc powder particles can promote apoptosis of myocardial infarction heart infarction area;7.Serum interleukin 11(IL-11)content: Compared with the control group,IL-11 in the serum of the myocardial infarction group and the particulate matter decreased,but there was no statistical difference(P>0.05).At the same time,there was no significant difference in serum IL-11 between the particulate matter and the myocardial infarction group(P>0.05);8.Serum catecholamine results 8.1 Serum adrenaline expression levels: Compared with the control group,the adrenaline in the serum of the myocardial infarction group and the particulate matter group was significantly increased(P<0.05).At the same time,the adrenaline in the serum of the particulate matter was significantly higher than that of the myocardial infarction group(P<0.05);8.2 Norepinephrine expression level: Compared with the control group,there was no significant difference in serum norepinephrine content in the myocardial infarction group(P>0.05).At the same time,norepinephrine in the serum of the particulate matter was significantly higher than that of the myocardial infarction group(P<0.05);8.3 Dopamine expression levels;there was no significant difference in serum dopamine between the myocardial infarction group and the particulate matter group compared with the control group(P>0.05).At the same time,there was no significant difference in dopamine in the serum of the particulate matter group compared with the myocardial infarction group(P>0.05).Conclusion: 1.Ultrafine nano zinc particles can cause further reduction of cardiac function in mice with myocardial infarction;2.Ultra-fine nano-zinc particles increase the collagen content in the infarcted area of mice,aggravate the degree of myocardial fibrosis,and at the same time,the cardiomyocytes are hypertrophied,the cells are arranged in disorder,and the apoptosis of cardiomyocytes is increased,thereby aggravating the rational remodeling of heart disease.However,there is no detailed effect on myocardial cell proliferation after myocardial infarction;3.Ultrafine nano zinc particles do not affect the expression of IL-11 and dopamine in the serum of mice,but can increase the content of adrenaline and norepinephrine in serum,indicating that they can excite the sympathetic-adrenal medulla system through body fluids.Changes in the environment exacerbate changes in cardiac functional structure and exacerbate heart function deterioration. |
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