The Experimental Study Of The Radiosensitization Efect Induced By Vinorelbine In Cultured Human Lung Adenocarcinoma Cells

Objective: To investigate the radiosensitization effect by vinorelbine in cultured human lung adenocarcinoma cells, and investigates the possible damage mechanism of vinorelbine.Methods: After exposed to vinorelbine,viability of cultured human lung adenocarcinoma cells (PAA) assessed by MTT colorimetric assay. The PAA were divided into four different groups-control group, pure radiation group , pure medicine group , medicine and radiation group-randomly after synchronization. The cell generation cycle and apoptosis rates of PAA in each group were checked by Flow cytometry, which were used to detect cell nucleus signed by PI; The number of survival cells of each group at different times was detected by MTT colorimetric, and their doubling time calculated and their growth delayeffects contrasted.Results: (1) Detection of MTT colorimetric assay: 24 hours later, the inhibition ratio of different concentrations (20, 40, 60, 80, 100 μ mol/L)of NVB are 6.12%, 18.80%, 53.91%, 77.10% and 90. 20%. This inhibition on PAA appeared to be dose-dependent, and 50% inhibitory dose(ID50) when PAA were affected 24 hours later was 59.1 μ mol/L; Moreover, cyto-inhibition was not obvious when low concentration of NVB (10 μ mol/L) while not only distinctive but also appeared to be time-dependent when high NVB(60 μmol/L). (2) Radiosensitization effect model was PAA given by 40 μmol/L vinorelbine as well as large dose (6Gy) radiation for Master single test . The cell generation cycle analysis of Flow cytometry assay show that compared with the control group the proportion of cells at G₂/M stage increased obviously. The test of apoptosis percentage show that compared with the control group apoptosis in pure medicine group occur after 24 hours, visible apoptotic peak in pure radiation group appeared after 12 hours, yet earlier and more obvious apoptotic peak (AP) in medicine combined radiation group. Mean apoptosis percentence rate of each group at different times in C group is 5.362 ± 4.123, R group 6.523 ± 6.214, Ngroup 9.985 ± 9.023, (N+R)group 18.10 ±8.965. N+R group compared with C, N,R group was significant in statistics (P<0.05) ;(3) The number of survival cells of each group at different times and their doubling time tested by Flow cytometry assay show that compared with the control group, pure medicine group and pure radiation group turned out to be different degrees of growth delay, but more obvious in medicine combined radiation group, in which the survival cells were half of the control group after 48 hours. Meanwhile, the interval of the doubling time was approximate 48 hours, about 12 hours more than that of the pure medicine and the pure radiation group.Conclusions: Vinorelbine increased the radiosensitization effect in cultured human lung adenocarcinoma cells.