Effect Of Positive Acceleration On Interleukin-6and Myocardial Structure Of Miniature Swine Accompanying Coronary Artery Stenosis

Objective：To study the maximum positive acceleration (+Gz)about miniature swinemodel accompanying coronary stenosis at different levels,and the effect of interleukin-6and myocardial microstructure of each group under the maximum+Gz exposure.Methods：Bama miniature swine were taken as study object to establish the model ofleft anterior descending artery stenosis at different levels in thoracoscopic. Withcoronary angiography to determine the degree of stenosis (20%to49%as mild stenosis,50%to69%as moderate stenosis,70%to90%of severe stenosis). Make each groupsexposed to high+Gz environment, and the standards to stop+Gz exposure is the samelead appearing more than three times premature ventricular contractions or ventricularfibrillation and so on. The maximum tolerated positive acceleration values and IL-6levels before and after exposure to positive acceleration were observed. Meanwhile, themicrostructure of anterior wall tissue of left ventricular were observed under light andelectron microscopes respectively.Results：1. The maximum acceleration tolerance values in each group: sham controlgroup was8.00±0.71+Gz; mild stenosis group was7.71±1.11+Gz; moderatestenosis group was6.00±0.89+Gz; severe stenosis group was5.20±0.84+Gz.Between the control group and the group with mild stenosis is no statistical significance,and moderate stenosis group and the control group、severe stenosis group and thecontrol group、moderate stenosis and severe stenosis group were statistically significant. 2. The IL-6levels within each group after+Gz exposure were statistically significant.The IL-6levels between the groups after+Gz exposure: between the control group andthe group with mild stenosis is no statistical significance; between coronary stenosiswith moderate and the control group, between coronary stenosis with severe and thecontrol group,and between coronary stenosis with severe and coronary stenosis withmoderate were statistically significant.3.Light microscope observations: Goodconnection between endocardium and myocardium,myocardial cells were packedtightly,and no edema in interstitium in pseudo-surgery control group; myocardial cellwas partly deformed, slightly increased of the gap, and slight edema in interstitium inmild stenosis group; Edema in intima cells,myocardial cells became irregular, partiallyruptured,and the gap was widened in moderate stenosis group; myocardial cells weresignificantly deformed and disorganized,and the gap was widened significantly, eventhe nuclei was deformed and shed in severe stenosis group. Electron microscopeobservations: Muscle fibers were arranged neatly, sarcomere clear and mitochondriaarranged regularly in pseudo-surgery group; Muscle fibers were slightly blurred,mitochondrial accumulated,and the inner ridge was blurred and reduced in mild stenosisgroup;Muscle fibers are fuzzy, mitochondria accumulated obviously and vacuolized inmoderate stenosis group; Muscle fiber was ruptured, mitochondria deformed severely,and cristae was concentrated, part of mitochondria broken in severe stenosis group.Conclusion:1. The more severe coronary artery stenosis of model pig, the lowermaximum acceleration values.2.At maximum acceleration tolerance conditions,moderate and severe coronary stenosis model IL-6levels were significantly elevated,and coronary artery stenosis was heavier,IL-6increased more significantly,and may beassociated with severe degree of inflammation.3.these two groups ventricular myocytesstructure change significantly by light and electron microscope, and coronary arterystenosis was heavier, myocardial injury changed more obvious. Mild coronary stenosiswas no significant change.