Study On Lethal Effect Of Combining [5-～(125)I] Iodo-2' Deoxyuridine With A Balanced Deoxyribonucleoside Mixture On Rat C₆ Glioma Cells

Objective: a)To study the lethal effect of culture times and radioactive concentration of 125I-UdR on rats C6 glioma cells. b)To study the lethal effect increased by a balanced deoxyribonucleoside.Method: a)Rats C6 glioma cells were cultured with medium of various radioactive concentrations for 24 hours , then the lethal effect was observed through surviving fraction and rate of apoptosis estimated by FCM. Meanwhile, cells were cultured with 125I-UdR for various times to evaluate the result of surviving fraction, b) Rats C6 glioma cells were cultured with medium of 74KBq/ml 125I-UdR and various AUCG concentration for 24 h . The effect increased was observed through morphology of cells , surviving fraction ,TEM and agarose gel electrophoresis. And cells were cultured with 74KBq/ml 125I-UdR and 30 M AUCG for various times to evaluate the result. Results: a) After being-cultured for 24 h, morphology of cells changed to circling , shrinking ,abscission and the number of seeding reducing. Surviving fraction decreased with increasing of radioactive concentration. In comparison, there was statistical significant in cells treated with 125I-UdR. Meanwhile, rate of apoptosis through FCM increased with radioactive concentration . The most rate of apoptosis is about 20%. Under various times ,surviving fraction reduced with time and it was twice in 24h than in 48h. b)Cells were co-cultured in 74KBq/ml 125I-UdR medium having different concentration of AUCG for 24h, and the phenomenon of cell-declining was enhanced. The phenomenon of chromatin locating the margin of karyotheca and dense nuclear as well as apoptotic body can be found through TEM , ladder-strip can be observed byagarose gel electrophoresis . The fraction of cell survival was negative correlated withtime.Conclusion: a)The lethal effect of 125I-UdR on rat C6 glioma cells was observed and itwas increased by prolonging the time of co-cultivating. The mechanism of cell-killingmaybe due to apoptosis. b) The lethal effect of 125I-UdR on rat C6 glioma cells wasenhanced by adding a balanced deoxyribonucleoside mixture , and it was moreeffective at low concentration of AUCG while disappeared at high concentration. It'spossible that AUCG enhanced the incorporation of 125 I-UdR into DNA and thus inducedthe apoptosis of cells.