| BackgroundWith the rapid development of science and technology, the application ofelectromagnetic radiation is more and more widely, such as communication, networking,and medical equipment etc.. And the relationship between electromagnetic radiation andpeople is getting close. The importance of the magnetic field is getting more attention ofpeople gradually. Studies showed that the electromagnetic radiation can damage humanbodies. Instead there is also a research shows that electromagnetic radiation can be used asa safe and effective means of physical therapy, These difference of these results depend onthe intensity of electromagnetic radiation, frequency, time, etc. Recently, according toreports of ischemic heart disease, there is a higher trend in mortality.Ischemic heartdisease has become a threat to human health and life[1]. The development of ischemicheart disease is closely related to the damage of myocardial microvascular endothelialcells. Thus promoting endothelial regeneration is a major means of treatment of ischemicheart disease. There are many similarities between microvascular endothelial cells andendothelial cells in the function. It is involved in blood vessel regeneration and play an important role in curing the cardiovascular disease. And the expression of connexin43isclosed with vascular cell in many facts, such as growth, apoptosis, migration,inflammation and so on. And Cx43is regarded as one of the marker protein of CVD[3]. Sowe can find a safe and effective condition of electromagnetic radiation. It can promote theregeneration of the microvascular endothelial under this condition, which makeangiogenesis and treat ischemic heart disease. This study which in rat cardiacmicrovascular endothelial cells, aims to find the effect of low frequency pulse magneticfield on myocardial microvascular cells cultured in vitro and the expression of the Cx43.Furthermore, the study investigate the mechanism of myocardial microvascularendothelial cell which exposed in the low frequency pulse magnetic field. It providetheoretical basis and reference for clinical treatment and appropriate parameter ofmagnetic field treatment.Methods1．Using trypsin and collagenase digestion method isolated SD adult rat microvascularendothelial cells, with differential adhesion method purified adherent cells.Observed withmicroscope. Detected the expression of cell specific protein factor VIII and vWF and usedphagocytosis experiment to identify cells. Used flow cytometry instrument to detect purityof CMECs.2．Rat cardiac microvascular endothelial cells were exposured to low frequency pulsemagnetic field.The cells were randomly divided into a control group and the irradiationgroup. Irradiation time:4h/d, continuous7d, exposure frequency:15Hz, the field strength:0.8mT,1.4mT and1.8mT. Use MTT method to detect cells proliferation; use streamingtechnology to detect the changes of myocardial microvascular endothelial cell cycle underdifferent dose; use scratch test and transwell method to detect migration and invasionability of myocardial microvascular endothelial cells under different exposure dose.3. Use real-time quantitative polymerase chain reaction (PCR) to detect Cx43mRNAcontent changes of myocardial microvascular endothelial cell under different dose. Theprotein immunoblot method is used to detect changes of Cx43protein and p-Cx43proteinin myocardial microvascular endothelial cell under different dose. The protein immunoblot method is used to detect content changes of ERK, p-ERK protein inmyocardial microvascular endothelial cell under different exposure dose in MAPKpathway.Results1. Successfully cultured cardiac microvascular endothelial cells and purified. CMECswere observed in paving stone sample characteristics under the microscope afterpurification. CMECs VIII factor and specific proteins in vWF were tested positive.Dil-Ac-LDL phagocytosis experiment showed CMECs were red. Flow cytometrydetection, purity of CMECs was97.27±0.83%.2.1.4mT and1.8mT electromagnetic pulse magnetic field can improve the level of cellproliferation. Meanwhile promoted cell migration, and invasion ability. The differencewas statistically significant (p<0.05).1.8mT electromagnetic pulse magnetic field canpromote NO secretion. The difference was statistically significant (p <0.05). After0.8mTlow-frequency electromagnetic pulse treatment, the change of cell proliferation,proliferation cycle, migration, invasion ability and NO secretion was no statisticallysignificant difference compared with control group (p>0.05).3.1.4mT and1.8mT electromagnetic pulse magnetic field increased the Cx43proteintranscription and translation level. And in these conditions the ERK and p-ERK levelswere increased. The differences were statistically significant (p<0.05). The changes ofJNK and p-JNK levels were not statistically significant (p0.05). After0.8mTlow-frequency electromagnetic pulse treatment, Cx43protein changes in the level oftranscription and translation, and changes of ERK, p-ERK, JNK, p-JNK levels were nosignificant difference compared with control group (p>0.05).Conclusion:1. The low frequency pulse magnetic field can improve the appreciation ability ofcardiac endothelial cells; promote cells into the G2phase and S phase; increase thesynthesis of DNA. The low frequency pulse magnetic field can promote cell migration,invasion.2. Low frequency pulse magnetic field can increase the level of Cx43transcription and translation, and raise the MAPK pathway of ERK and p-ERK protein levels. Theseshowed that low frequency pulse magnetic fields may regulate the expression of Cx43, inturn, promote the cell biology ability. |
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