Selective Apoptosis Of The K562 Cells Induced By High Intensity Pulsed Electric Fields

The thesis mainly studied the selective apoptosis of theerythroleukemia K562 cells and lymphocytes cells induced by the highintensity pulsed electric fields, which was parts of the project"Selective apoptosis of cancer cell in blood induced by high intensitypulsed electric fields" that subsidized by Innovation Fund of JilinUniversity.The leukemia is one of the top-ten malignant tumors, taking 5% inthe incidence of the cancer. In the mortality of malignant tumors withdifferent ages, the leukemia came on 3.48% in males, occupying thesixth, and 4.11% in females, occupying the eighth, and occupying thefirst in the under-35 and children. According as the data of the leukemiaincidence of each country throughout the world in the past years, theleukemia incidence, in particular the acute-leukemia incidence has theincreasing trend year after year. In the face of high incidence and highdeath of the leukemia, there are still a great many problems in thehematopoietic stem cell transplantation and chemotherapeutics, whichare the primary therapies of the leukemia, and they could not help thepatients of the leukemia come back completely.Recently, pasteurizating liquid stuff by using a high intensity pulsedelectric fields is a new technology of non-thermal pasteurization. Thehigh intensity pulsed electric fields have the characteristics ofuniformity in conducting heat, shot processing time, low energyconsumption and low quantity of heat, and the technology of PEF is theone of the primary non-thermal pasteurizations. At present, the researchin application of the high intensity pulsed electric fields mostly focusedon the food pasteurization, which has got some very good effects inpasteurization. The application of the PEF technology is a new effectivemedical treatment in treating leukemia, and the research of the problemwill add the therapy method of leukemia. The research of high intensitypulsed electric fields inactivating leukemia cells could help peopleimpair the limits of side effects in treating malignant tumors byhematopoietic stem cell transplantation, chemotherapeutics andirradiation therapy, which can save on the therapy expenditure, reducethe stress and suffering endured by leukemia patients. The research ofthe problem can not only offer scientific data in medical treatment andalso have great significance in society, which will make hugecontribution for people health.This paper, combining the development of the PEF, manufactured ahigh intensity pulsed electric fields, and changed the technicalparameters of the PEF setting with the pasteurizations mechanism byPEF, to selectively induce apoptosis of the K562 leukemia cells andlymphocyte cells. Finally the author obtained the main findingssummarized as follows:1. When observing the erythroleukemia K562 cells, which wasinduced by the high intensity pulsed electric fields detected withtransmission electron microscope, we may find many vacuoles andcrannies in cells, mitochondria swelling, vacant, shelvse of the innermembrane break, the heterochromatins are on the edge,nuclear pycnosis,nuclear fragmentation. The ultrastructure approves that the highintensity pulsed electric fields can make huge damage in K562 cells andinduce K562 cells apoptosis.2. From the analysis of orthogonal array, we can know when weinduce the K562 cells apoptosis by the high intensity pulsed electricfields, the PEF strength and pulse number are significant factors,thereinto, the PEF strength is dominant and pulse extent is notsignificant.3. The best parameter combination is A1B3C3 in the apoptosis ofK562 cells by PEF, that is the pulse extent is 1μs, the PEF strength is25kV/cm, the pulse number is 10 and the PEF pulse is 30Hz. Theapoptosis rate is 59.65% in the best condition.4. From the observation in FCM, we can find that the apoptosisrate of K562 cells increases gradually along with the hoist of the PEFpulse number, when the PEF strength and pattern's velocity of flowhold the line, and the biggest apoptosis rate of the K562 cells is 59.13%,P<0.01, when the PEF pulse number is 10. Meanwhile The apoptosisrate of lymphocyte cells achieve 40.08% in 10 PEF pulse number from8.40% in 4 PEF pulse number, and when the pulse number is 10, theapoptosis rate of lymphocyte cells get the biggest 40.08%, there issignificant difference, P<0.01.5. From the graphs of the K562 cells and lymphocyte cells inducedby the PEF, we can be conscious that the apoptosis rate of the K562cells and lymphocyte cells is close in the change of the PEF pulsenumber, when the PEF pulse number is 10, the difference in apoptosisrate of the K562 cells and lymphocyte cells is the biggeat.6. When the the PEF pulse number and pattern's velocity of flowhold the line, the apoptosis rate of the K562 cells increases along withthe PEF strength, from the 2.73% in 0kV/cm PEF strength to 86.81% in30kV/cm, and after 20kV/cm PEF strength, the apoptosis rate of theK562 cells tends to immovability, which accounts for the apoptosisaction in the K562 cells induced by the PEF is very notable. Besides inthe same conditions, the apoptosis rate of lymphocyte cells alsogradually increases along with the PEF strength, when the PEF strengthis 20kV/cm or bigger, the apoptosis curve of lymphocyte cells tends tobe smoothed line, and there is the biggest apoptosis rate 47.08% in30kV/cm, P<0.01.7. In the test of the PEF strength, there is a notable difference inthe apoptosis rate of the K562 cells and lymphocyte cells induced bythe PEF, the apoptosis rate of the K562 cells is higher than thelymphocyte cells, which shows that there is a feasibility of selectiveapoptosis of cancer cells by high intensity pulsed electric fields, andthe PEF strength is the fateful factor.8. When the PEF strength is from 22kV/cm to 30kV/cm, there isalways about 30% difference in the apoptosis rate of the K562 cells andlymphocyte cells induced by the PEF. Therefore when the pulse numberis 10 and the PEF strength is from 22 kV/cm to 30kV/cm, the PEF caninduce the cancer cells selective apoptosis ,which are the best effectiveparameters.9. When the pulse number is 10, the pattern's velocity of flow is5.65mm/s, and the PEF strength is from 30kV/cm, the apoptosis rate ofthe K562 cells can achieve the highest, and there is 33.76% bigger thanthe lymphocyte cells in difference.