Juntao Wang, Haijia Yu, Huihui Song, Yapan Yang, Leiming Zhang, Hongxing Luo, Panpan Chen and Yinjie Chu*
Department of Cardiology, Zhengzhou University People’s Hospital, Zhengzhou, Henan, China
Received: 21 April, 2017; Accepted: 12 May, 2017; Published: 13 May, 2017
Yinjie Chu, Department of Cardiology, Zhengzhou University People’s Hospital, Zhengzhou, Henan, China, Tel: +86 13937199780; E-mail:
Wang J, Yu H, Song H, Yang Y, Zhang L, et al. (2017) The Changes of Myocardium in Minipigs after Coronary Vein Ligation Observed by Transmission Electron Microscopy. J Cardiovasc Med Cardiol 4(2): 020-022. 10.17352/2455-2976.000042
© 2017 Wang J, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Coronary vein; Ligation; Cardiomyocyte; Auto phagosome; Angina
Background: The study of coronary artery disease has been quite thorough. But there is few study on coronary vein disease. In clinical practice, some patients have suspicious symptoms of coronary artery disease without any evidence of coronary artery spasm, but coronary angiography showed no obvious stenosis in coronary artery. It may have relationship to coronary venous dysfunction. This study aims to develop a coronary vein ligation model, to investigate the effect of coronary vein occlusion on myocardial cells in normal miniature pigs.
Methods: Adult minifies were divided into control group and intervention group. The coronary venous occlusion model was made by clamping the central vein. Myocardium was isolated from the myocardium and the myocardium was observed by transmission electron microscopy.
Results: There were no significant changes in the sham operation group (control group). Mitochondrial edema, cristae broken, hyperplasia and auto phage some appeared in the operation group (intervention group).
Conclusion: The ligation of the coronary vein causes dysfunction of myocardial cells. It gives us inspiration, coronary vein occlusive disease may be underestimated. It may be some causes of angina for patients with normal coronary angiography.
Cell is a complete individual with complex structure, which can be used to carry out a variety of metabolic activities orderly, thus to complete a variety of physiological functions. At the same time, certain cell has adaptability to make different corresponding changes to different external stimuli. Particular, changes in the micro aspects affect cell function directly, thus to interrupt the affiliated organ’s function, and eventually they are reflected to the whole-body level.
For so many years, due to the research development of coronary artery disease, studies on the effect of coronary ischemia and ischemia-reperfusion on myocardial cell micro level emerge in an endless stream. However, there are patients with normal coronary angiography without any evidence of coronary artery spasm, but angina symptoms [1-3]. Diagnosis with cardiac neurosis or microcirculatory disturbance remains insufficient . There are research papers about coronary vein stenosis [5,6], especially, recent years, there were case reports about normal coronary angiography, but stenosis was found in coronary vein angiography .
Pathology and diseases of coronary sinus and veins are very rare [8,9]. They are most frequently mentioned with iatrogenic injury during mitral valve surgery or as a part of diffuse allograft vasculopathy after cardiac transplantation. Therefore, we doubt if there exists primary coronary venous disease. In this paper, we observed the micro-changes of myocardial cells after coronary vein ligation with transmission electron microscopy (TEM), aiming to explore the micro morphological and provide basic theoretical data for coronary vein stenosis and occlusive diseases.
Material and Methods
The experiments were performed in 6 male approximately 5 months’ old Guizhou minifies with an initial average body weight of 20–30 kg. The investigation conformed to the Guide for the Care and Use of Laboratory Animals published by the U.S. National Institutes of Health , and the protocol was approved by the Institutional Animal Care Committee from Zhengzhou University People’s Hospital, People’s Republic of China. Pigs were divided into 2 groups: sham operation (n = 1), which was performed by opening the chest without coronary vein ligation (control group), and operation (n = 5), which was performed by opening the chest coronary vein ligation (intervention group).
Preoperative anesthesia, tracheal intubation and ventilator parameters
Pigs were intramuscular injected with diazepam (2mg/kg), atropine (0.06 ~ 0.08mg/kg) and ketamine (20mg/kg). And in 3 ~ 5 minutes, pigs stood instability and lay down, show that the successful induction of anesthesia. Anesthesia was maintained by 3% pentobarbital sodium. The ventilator was adjusted to the following parameters: 0.5L/min tidal volume, respiratory rate = 18/min, inhaled oxygen concentration (FiO2) =60%, inspiratory and expiratory time ratio = 1:2, positive end expiratory pressure (PEEP) = 0.49Kpa (5cm H2O) .
Coronary vein occlusion model
Sternotomy was performed on the sternum, up to the sternal notch, down to position 1 – 2 centimeters under the xiphoid tip. Eight to ten centimeters’ longitudinal incision was made to expose the heart, then we cut the pericardium, and 7-O polypropylene suture was used to fix and suspend pericardium . The coronary sinus was exposed to make clear the location of the middle cardiac vein. The middle cardiac vein proximal the coronary sinus was ligated in the intervention group with 7-O polypropylene suture. Pigs in the control group was dealt only with 7-O polypropylene suture encircled the middle cardiac vein.
Necessary equipment and fixing fluid were prepared in advance, and was put in the refrigerator set for 4. Animals were sacrificed after 4-hour coronary vein ligation by intravenous injection of potassium chloride under anesthesia. And hearts were removed, and then middle cardiac veins and the myocardium nearby the middle cardiac vein was isolated. The tissues were rapidly washed with saline, put in the 2.5% glutaraldehyde solution on the plate coated with a fixed liquid wax, then cut into about 1 mm3 cube or cuboid with a cross-section of about 1 mm2 with double blade method. And then 2-3 small myocardium was taken into a fixed liquid bottle (marked with mark pen and sealed with medical tape) with a toothpick. Fixed with 1% osmium acid, small myocardium was dehydrated, mounted, ultramicrocut, electron stained, and observed under the TEM .
1. TEM showed that, most of myocardial cells formed into bundles, fibers were with clear boundary, longitudinal showed obvious periodic stripes, every fiber was nearly parallel arranged with a few of weaves. There was no obvious abnormal change of myocardial ultrastructure, the muscle membrane was complete, the muscle fibers were arranged in order, sarcomeres were clear to identify, the mitochondrial lamellar structure was well preserved, the cristae were thin and dense (Figures 1A, 1B).
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