| ObjectiveTo explore? the efficacy and safety of paclitaxel concurrent chemoradiotherapy for H22 hepatic carcinoma of mice, and observed the radiosensitizing effect of paclitaxel.Methods(1)?Recovered, Passaged and Cultured H22 cells. when the cells entered the logarithmic growth phase. they were respectively treated with paclitaxel of 0.006mg/l,0.06mg/l,0.6mg/l,6mg/l,60mg/L,600mg/l about 24h, and observed cells morphology by inverted microscope, then determined the inhibition effect of paclitaxel on the growth of H22 cells by MTT assay, calculated IC 50, IC10, and inhibitory ratio in IC50. Pretreated H22 cells with paclitaxel that consistency of IC10, and irradiated withγ-ray of 2Gy dose at 6h, 12h, 24h, 36h, 48h after treatment, observed cells morphology by inverted microscope, then determined the radiosensitizing effect of paclitaxel by MTT assay. (2) Mice models of liver cancer were established by subcutaneous injection of H22 cells, H22 bearing mice were randomly divided into 8 groups: control group, PTX1, PTX2, PTX3, irradiating group, chemoradiotherapy group 1, chemoradiotherapy group 2 and chemoradiotherapy group 3, 20 mice in every group. PTX1, PTX2, PTX3 were pretreated with paclitaxel of 10mg/kg, 30mg/kg, 60mg/kg respectively; irradiating group was irradiated withγ-ray of 2Gy/d×5d dose; chemoradiotherapy groups were irradiated withγ-ray of 2Gy/d×5d dose at 12h after pretreated with paclitaxel of 10mg/kg, 30mg/kg, 60mg/kg dose respectively; the mice were not pretreated in the control group. After treatment start, each tumor's volume was measured on alternate days. Detected the growth rate of every groups, calculated the q value. Selected and euthanized 8 mice bearing H22 tumor randomly on day 14, took blood samples before euthanizing, tumors were stripped and the weight of thymus gland, spleen, tumor were measured after euthanizing, The tumor-inhibition ratio, thymus index and spleen index in mice were reckoned. Counted WBC and detected alanine aminotransferase level. The changes of pathological characteristics and microvessel density and apoptosis index in tumors were observed by Hematoxylin-Eosin and Immuno-histochemistry staining. Each mice bearing tumor were used to observe survival time in every group.Results(1) After pretreated by paclitaxel of different concentration respectively, the inhibition ratio of H22 cells increased with the increase of concentration. The concentration of IC50 was 1.948mg/l, IC10 was 0.390mg/l; the inhibition ratio in paclitaxel concentration of IC10 was 0.5003. Results of analysis of variance showed that there were statistically differences of A value among different paclitaxel concentration groups (F=736.945, P=0.000), different concentration groups except 0.006mg/l group vs 0mg/l group (P=0.272) showed statistically difference (P=0.000). After treated by paclitaxel of concentration of IC10 for 6h, 12h, 24h, 36h, 48h respectively, the H22 cells were irradiated byγ-ray, Results of analysis of variance showed that there were statistically differences of A value among different pretreating time groups (F=53.165,P=0.000), different pretreating time groups except 24h vs 48h group (P=0.080) and 36h vs 48h (P=0.442), showed statistically difference (P<0.05). From the first 12h the interaction effects appeared between paclitaxel and irradiation (F=10.843, P=0.011). The SER of each time groups was 1.24, 1.52, 1.87, 1.95 and 2.06 respectively. With the increase in time of pretreatment, SER increase gradually, pretreatment of 6 h~12 h, SER increase fastest, from 24h SER became growing slowly. (2) There was statistically difference among tumors growth rate in different treating group (F=318.152,P=0.000), The tumor growth delay and growth inhibition ratio increased in the 3 chemoradiotherapy groups, All the q value was more than 1 (1.30±0.19,1.42±0.17,1.50±0.17). Results of analysis of variance showed that there were statistically differences of the tumors'weight among different groups (F=255.730,P=0.000),the tumors'weight of PTX1, PTX2, PTX3, irradiating group, chemoradiotherapy group 1, chemoradiotherapy group 2 and chemoradiotherapy group 3 were less than control group, the tumor-inhibition ratio was 5.19%, 16.99%, 20.57%, 31.37%, 52.47%, 60.04% and 70.81% respectively, interaction effects existed between paclitaxel and irradiating (F=21.201,P=0.000). The thymus index, spleen index and WBC counts of chemoradiotherapy groups were less than control group(P<0.05). The alanine aminotransferase level of chemoradiotherapy groups increased except chemoradiotherapy group 1. The interaction effects between paclitaxel and irradiating did not decrease WBC counts or increase alanine aminotransferase level (P>0.05). The microvessel density of chemoradiotherapy groups were less than control group ( P<0.05 ) except chemoradiotherapy group 1, The interaction effects between paclitaxel and irradiating did not decrease microvessel density (F=0.245,P=0.865).The apoptosis index in tumors of chemoradiotherapy groups were higher than that in non-? chemoradiotherapy groups( P<0.05) , the interaction effects between paclitaxel and irradiating could stimulate apoptosis( F=6.381, P=0.001) . Average increase of life span in PTX1, PTX2, PTX3, irradiating group, chemoradiotherapy group 1, chemoradiotherapy group 2 and chemoradiotherapy group 3 was 13.25%, 44.87%, 55.13%, 32.91%, 73.08%, 98.29% and 59.83% respectively. There were statistically differences about survival ratio between chemoradiotherapy group 2 and non-?chemoradiotherapy groups (P<0.01). Conclusion(1) The IC50, IC10 of paclitaxel for H22 cells was 1.948 mg/l and 0.390mg/l. Paclitaxel of IC50 concentration showed moderate to high sensitivity on H22 cells. From the first 12h the interaction effects appeared between paclitaxel of IC10 and irradiation. (2) The efficacy of paclitaxel concurrent radiotherapy for H22 tumor was superior to non-combination groups in vivo, paclitaxel had significant radiosensitizing effect on H22 tumor. The major side effect was hematotoxicity. Paclitaxel of 30mg/kg concomitant radiotherapy had most advantage in improving survival ratio. |
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