Shen Mai Injection Injury Intervention Effect Of Acute Myocardial Ischemia And Hypoxia

Ischemic heart disease is a serious disease which threatens the sufferer's life orinfluences their living quality. It's always the focal point of medical research in searchingmedicament with good curative effect and fewer side effects to prevent and cure it. Chinesemedicine is the cream of Chinese classical civilization. There are many excellent directionslike Sheng Mai San in curing acute and chronic ischemic heart diseases -"chest and heart painsyndrome" in Chinese medicine. Shen Mai injection is a modern Chinese patent medicineimproving from Sheng Mai San. With the injection form, it applies in clinic more widespread,especially in saving acute myocardial infarction patient. A good many reports were made onstudying Shen Mai injection, but more of those were clinical use. In order to explain themechanism of Chinese medicine and make Chinese medicine accepted all over the world, weneed to do some work going deep into the mechanism of Shen Mai injection protectingischemic heart.This research is based on sorting out and analyzing a great deal reference data, on theintegral and cellular levels, discuss the protecting mechanism of Shen Mai injection using"toxin injury heart collaterals" theory. At the same time we try to find out the key point ofShen Mai injection inhibiting cardiomyocyte apoptosis, proceeding from the most importantorganelle of cardiomyocyte - mitochondria.The experiment part of this research includes two segments. The first one observes effectof Shen Mai injection on morphology changes and oxidation stress after rat acute myocardialinfarction. The second one probes into the key point that Shen Mai injection reversesmitochondria apoptotic pathway in anoxia cardiomtocytes.Methods1 In vivo experimentThe left anterior descending coronary artery of SD rat was ligated to make acutemyocardial infarction injury. Fifty six rats was divided into three group random: sham group(Sham), model group (M) and Shen Mai treating group (SM). Each group was observed bothin 6 hours and 12 hours. In SM group, rats were administered Shen Mai injection 4.3ml/kg·d 3days before operation, according to the proportion of body face of human and rat, and alsogiven 1 time an hour just before operation. Normal saline was injected to rats of M group andsham group.The rat heart tissue was cut sections for microscopic examination. HE staining andHBFP staining was to show tissue structure changes and state of ischemia. Ultrastructure ofheart tissue was observed by electron microscope. The CK-MB and LDH activity in serumrepresents the degree of heart injury. We also examined the SOD activity, MDA and NOcontent in serum and heart tissue, discussed the effect of Shen Mai injection pretreatment onischemic heart. 2 In vito experimentThe cultured neonatal rat cardiomyocytes were divided into 3 groups: control group(Control), anoxia group (M) and Shen Mai treating group (SM). Each group was observedboth in 6 hours and 12 hours. The cardiomyocytes were put in gas condition with 95%N₂ and5%CO₂ to make acute anoxia. Shen Mai injection was add to culture fluid from 24 hoursbefore anoxia in SM group in a dose of 5ml/L.Apoptosis was judged by cell cycle detection, early apoptotic percentage examination,DNA fragment detection, TUNEL and transmission electron microscope observation.Structure and function changes of mitochondria were show by MTT detection and laserscanning microscope observation labeled by Mito Tracker Green. And then we probed into thekey point of Shen Mai injection inhibiting cardiomyocytes apoptosis from mitochondriapathway like Caspase 3/7 activity, mitochondria membrane potential and intracellular calciumlevel.Results1 In vivo experiment(1) The structure of heart tissue was destroyed progressively after acute myocardialinfarction. Myofibril was disarranged observed by light microscope, and there wasfragmentation, myolysis, interfibrillar haemorrhage and ischemia. Showed in electronmicroscope, sarcomere arranged disordering, cross striation was not clear, and mitochondriawas swelling, colliquative and breaking. The number of crest decreased, and it's also breakingand lytic. Calcium phosphate deposited in mitochondria. Nucleolus was pyknotic, chromatincoagulated at side. The injury were more serious at 12 hours than 6 hours. Pretreatment ofShen Mai injection could alleviate the changes of heart tissue structure distinctly both at 6hours and 12 hours after infarction.(2) In serum the CK-MB activity of M group increased distinctly (P＜0.01), and theresult of M 12h was lower than M 6h (P＜0.01). The LDH activity in serum also increasedobviously (P＜0.01), and the result of M 12h was higher than M 6h (P＜0.01). In SM group,CK-MB activity in serum after infarction dropped considerably compared to M group(P＜0.01), while the LDH activity had no distinct change.(3) The SOD activity of M group in serum decreased both at 6h and 12h, and that theresult of M 12h was more serious (P＜0.01). The MDA content changed 12 hours afterinfarction (P＜0.01). In heart tissue, SOD activity and MDA content of M group only altered12 hours after infarction (P＜0.05, P＜0.01), and the NO content increased both at 6h and 12h(in M 6h P＜0.01). However, the SOD activity of SM group in serum ascended notablycompared to M group (P＜0.01), and the MDA content in heart tissue increased while NOcontent decreased (P＜0.05, P＜0.01).2 In vito experiment(1) Apoptosis could be checked both in 6h and 12h groups after anoxia, and the ratio was higher in M 12h group than in M 6h group (P＜0.01). Treatment with Shen Mai injection from24 hours before anoxia could reduce apoptosis at different time (P＜0.01).(2) Cardiomyocytes mitochondria in M group appeared to be swelling, rupture, numberdecreasing and low activity, the injury of M 12h was more grievous than M 6h(P＜0.01). Themitochondria function and structure was gentle in SM group(P＜0.01).(3) Cardiomyocytes of M group had higher activity of Caspase3/7, lower mitochondriamembrane potential and more intracellular calcium, and these changes altered dominantlywith long time anoxia (P＜0.01). Shen Mai injection had positive effect on these injury, itcould play down Caspase3/7 activity, raise the membrane potential and reduce intracellularcalcium level (P＜0.01).ConclusionThe occurrence and development of acute myocardial infarction accord with "toxininjury heart collaterals" theory in Chinese medicine. The product of oxidation stress andoverfull calcium etc. corresponds to the "inner toxin". Shen Mai injection nourishes qi and yin,relieves asthenia toxin and eliminate sthenia pathogenic factors. So it can inhibit oxidationreaction and reduce structure destroy of heart tissue caused by myocardial ischemia. At thesame time, Shen Mai injection can inhibit apoptosis induced by anoxia. The protectingmechanism relate to mitochondria apoptotic pathway, and the key point is the restrain oncalcium overload of cardiomyocytes.