An Archi-study On Platelet Concentrates With Gamma Irradiation

BACKGROUND & OBJECTIVE HBV,HCV,HIV-1/2 are mainly viruses which were propagated by blood products.Besides HTLV-1/2,HDV,HEV,CMV and parvovirus B19 could also be propagated.At present,ALT,HBsAg,anti-HCV,anti-HIV and syphilis were screened on blood donors in china which confined the spread of disease caused by blood-transfusion.But there are still exist the risk of blood-transfusion disease for confinement detection levels,internal window phase of detection technology and continuous generation of new viruses and variants.In view of this,inactivating potential viruses in blood products is an important measure which can ensure the safety of blood-transfusion.Gamma irradiation has bactericidal effect on many kinds of micro-organisms which certified by many experiments,the micro-organisms contains tunicary viruses,nonencapsulated viruses and all of genetype materials.At present,gamma irradiation was used to prevention of transfusion associated graft versus host disease.Gamma irradiation which generated when radioisotopes decayed could penetrate nucleated cells,have an directly irreversible damage to the nucleus of the DNA and interfere the process of normal repair,all of this could result in lossing activity of mitotic and stopping proliferation to Lymphocytes.The effect of irradiation is directly related with the dose of irradiation.According to the theory of using Gamma irradiation to prevention of TA-GVHD and inactive virus,we carried out the research on platelets' inactivation of virus with gamma irradiation.The dose used on prevention of TA-GVHD was based on,we increased the doses of radiation until inactive virus,while ensuring the preservation of platelet quality,functionality had no significant impact,this was the main contents of the research.METHODS This experiment was mainly preparatory work of study on platelets' inactivation of virus with gamma irradiation,the main contents were as follows:(1) The establishment of measurement for lactic acid in supernatant of platelets. principle:Lactate was dehydrogenated to pyruvate at the action of lactate dehydrogenase,at the same time NAD~+ received H~+ to yield NADH.According to the absorbance variances of NADH at 340 nm,the lactate level in supernatant of platelets was calculated.(2) Selection of indexes on evaluation of platelet quality on shelf life and the study on platelet injury on shelf life.We mainly selected metabolic indexes,such as pH values, glucose concentrations and lactate concentrations in supernatant,adenosine triphosphate levels,lactate dehydrogenase activity,leakage of lactate dehydrogenase. Eight samples of metabolic indexes were observed and evaluated on the first day,the third day,and the fifth day.(3) The influence of gamma irradiation on the quality of platelet concentrates on storage.Three unites of platelet concentrates were taken as samples.Each unit of platelet concentrates was divided into ten groups,one group served as a control,the rest of groups were gamma irradiated with 35GY,70GY,105GY,140GY,175GY,210GY,245GY,280GY,315GY respectively.Leakage of lactate dehydrogenase were detected immediately after irradiation,24 hours later and at the end of shelf life, then drawn dose-LDH leakage rate curve and observed the change trend.One unit of platelet concentrates was taken as sample,divided into several groups and freeze preserved.Drawn freeze time-LDH leakage rate curve and was contrasted with the irradiation groups.Eight unites of platelet concentrates were taken as samples,each unit of platelet concentrates was divided into five groups,one group served as a control,the rest of groups were gamma irradiated with 175GY,210GY,245GY,280GY respectively.LDH leakage rate was detected and analyzed with statistics immediately after irradiation and at the end of shelf life.Eight unites of platelet concentrates were taken as samples and divided into two groups,one group served as a control,the other group were gamma irradiated with 245GY.Several indexes were detected and analyzed between irradiation groups and control groups. RESULTS(1) Established a multipoint method for detecting lactate level by dehydrogenase and made a foundation for detecting it in supernatant of platelets.(2) On the process of storage,glucose was consumed,lactate generated and pH descended gradually,ATP was utilized,leakage rate of lactate dehydrogenase increased. (3) Leakage rate of lactate dehydrogenase has unchanged tendency at the time of immediately after irradiation and 24 hours later.But at the end of storage,leakage rate of lactate dehydrogenase increased with the increased dose,there was an obvious change after 175GY.Leakage rate of lactate dehydrogenase with 245GY was higher than the control groups at the end of storge,but there were no influence on pH values, Glu,LA,ATP with this dosage.CONCLUSIONS Irradiation is an chronic injury process for platelet concentrates,it has a slight influence at the time of immediately after irradiation and has a significance influence at the end of storage(fifth day) with the 245GY dose.