| Backgroud and aimOxygen free radical and calcium overload are two important factors in myocardial ischemia injury. Both of the two factors are correlated closely with myocardial mitochondrion. First, because of the sensitive of mitochondrion to oxygen free radical's toxic effect, Oxygen free radical acts to mitochondrion membraneand leads to membrane phospholipid degradation and fluidity decending; second, the injury of myocardial membrane and deficiency of ATP results in that the cell membrane and calcium pump of sarcoplasmic reticulum can't work normally, which leads to great increase of free calcium in myocardial cell and gives rise to the damage on function and structure of myocardial mitochondrion and muscle fiber. Present study investigated deeply the protective effect of Qidantongmai Tablet (QDTMT) on rat myocardial mitochondrion and ultrastructure with acute myocardial ischemia from three aspects: oxygen free radicals, calcium overload and cardiac myocyte ultrastructure. The purpose of this study was to supply reliable experimental basis for the clinic application of this medcine.Methods1. 32 SD rats, including male and female, weighting between 250-280g, were randomly assigned into four groups: normal control group, model group, QDTMT group, positive control group.2. By means of Subcutaneous injectting Isoprenaline (Iso), we reproducted the myocardial ischemia model. Based on the model, the contents of MDA, SOD, GSH-PX, ATPase and SDH in myocardial mitochondrion were measured by means of colourimetry. Besides, the content of Ca2+ and Mg2+ in myocardial tissue and mitochondrion were measured. The content of MDA and the activity of SOD and GSH-PX in peripheral circulation and the activity of SDH in cardial myocytes were estimated. Isolated the myocardium of apex of the rat heart and investigated the changes of myocardial ultrostructure under the transmission electron microscope.3. Isolated the myocardium of apex of the rat heart, embedded it into paraffin, then segment the sample, investigated the changes of myocardium under the light microscope.Results1. Conpared with normal control group, the activities of SOD^ ATPase and SDH in model group were lower while the content of MDA and Ca2+ in mitochondrion and the content of Ca2+in myocardium were increased (.PO.05) ; the content of Mg2+in myocardium was decreased significantly (P<0.05) . But, the content of Mg2*in mitochondrion did not change (P >0.05 )?2. Compared with the model group, the activities of SOD> GSH-PX ^ ATPase and SDH in QDTMT group were increased significantely (P <0.01) while the content of MDA and Ca2* in mitochondrion and the content of Ca2* in myocardium were decreased (P<0.01) , the content of Mg2+in myocardium was increased significantly(PO.05) .3. In the model group, the arrangement of myocardial myoflilaments was confused, the sarcomere were shorten, I zone and H zone were disappeared, mitochondrion were swollen, vacuolalization and the crest were disorder. Matrix granule was seen clearly in part of the mitochondrion.4. In QDTMT group, the sarcomere was clean-cut, myocardial myoflilaments were completed, the arrangement of myoflilaments were abnormity slightly. Mitochondrion were swollen slightly, the structure of vacuolalization and the crest were clear and regular.Conclusion and implication1. We can reproduce the rat acute myocardial ischemia model by means of isoprenalin injection.The myocardial ischemia induced by Iso is related with the increasing of oxygen free radicals and calcium overload in mitochondrion, which is corresponded with the documents. This study shows that Iso can decrease the activity of SOD, GSH-PX> ATPase and SDH in myocardial mitochondrion and Mg2+ in myocardial tissue while it can increase the the content of mitochondrial MDA ,Ca2+ in myocardial tissue and mitochondrion.2. QDTMT lessens the injury from oxgen free radical.QDTMT can increase the activity of SOD, GSH-PX, ATP ase and SDH in myocardial mitochon...
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