The Effect Of Taxotere On The Radiation Sensitivity Of The Lewis Lung Cancer

PurposeTo determine the radiosensitive effect of taxotere and discuss its mechanism.Materials and Methods1. Animals : C57BL/6 mice, male ,6-8 weeks ,from BEIJING university-2. Drug: Taxotere from Aventis company.3. Method of injectionBy pilot study, we gained the medium lethal dose ( LD₅0) of taxotere which is 152 mg/kg and defined 1/5 LD₅0,that is 30.4 mg/kg,as high dose; 1/10 LD₅0 ,that isl5.2 mg/kg, as low dose. The Lewis lung carcinoma cells were injected subcutaneously in the right hind legs of the C57BL mice.4. GroupWhen the tumours grew to about 0.93 ±0.12cm³, the mice were randomly assigned to six treatment categories. There were six treatment categories which had a total of 18 subgroups. Each subgroup consisted of seven animals. The first was the control category that had one group (n = 7). The second treatment category was taxotere alone, which had two groups as per taxotere dose alone (n = 14). The third treatment category was radiation alone, which had five groups as per the radiation dose (n = 35). The fourth treatment category was taxol plusradiation, which had 10 groups as per combined radiation dose plus taxol dose concentration(n = 70). The Denekamp's method of one time radiation was a-dopted.5. ObservationWe observed the tumour growth delay (TGD) , the sensitization enhancement ratio (SER) ,the survive time( ST) and the volume of tumor.6. Statistical analysisChoose the SPSS11.0 to analyse these data, mean ± standard deviation express quantitative data, and use variance to analysis the data. P < 0. 05 was considered significant.Results1. The impact to the volume of the mice' tumorThere were combined effects between radiation and taxotere ( P < 0. 05 ). But before operation all of the subgroups' tumor volume showed a non - significance. The radiosensitive effect of taxotere in radiosensitivity was similar in the high dose and the low dose groups.2. The impact to the tumour growth delayThe volume of the combining groups grew more slowly than the radiation a-lone groups.3. The impact to sensitization enhancement ratioThe sensitization enhancement ratio is 1. 35 - 1. 52. The effect of taxotere in radiosentisation was similar in the high dose and low dose groups.DiscussionTaxotere's unique effect of G₂/M block was proved in 1979 by Schiff. The microtubules could be polymerized by taxotere. So most of the tumor cells were in the G₂/M phase in which tumor cells were more sensitive to the radiation. Our results showed that the effect of taxotere in radiosensitivity was similar in the high dose and low dose groups. In this study, the radiation was started twelve...