人宫颈癌移植瘤照射过程中氧分压变化规律的研究

Study on oxygen tension change in xenograft tumor of human cervical cancer during irradiation

目的研究人宫颈癌移植瘤照射过程中氧分压变化规律。方法人宫颈癌HeLa细胞培养后接种于裸小鼠右后大腿外侧皮下,每鼠02ml。待肿瘤长至直径15cm以上时,用10MeV电子线照射裸鼠移植瘤及正常后腿,SSD为96cm,吸收剂量率为100Gymin,总吸收剂量400cGy。用极谱法测定裸鼠移植瘤及正常后腿氧分压,照射前及照射过程中每30秒分别记录肿瘤及正常组织的氧分压读数,持续至放疗后4min。结果①8只裸鼠,7只成活,其中7只成瘤,成瘤率875%(78)。瘤体平均(17585±02020)cm。②照射前移植瘤乏氧状况测定,瘤体平均氧分压(37857±06694)kPa,而正常后腿对照氧分压(117714±22787)kPa,二者差异有统计学意义(t=7678,P<001)。③正常组织照射中的氧分压与照射时间无关,r=0029,P=0940;肿瘤组织照射中的氧分压随照射时间的增加而降低,相关系数r=0927,P<0001;正常组织照射后的氧分压与照射时间无关,r=0446,P=0229;肿瘤组织照射后的氧分压随照射时间的增加而降低,r=0964,P<0001;肿瘤组织照射后的氧分压与照射前的氧分压相关,r=0993,P<0001。④肿瘤组织照射后的氧分压与照射前的氧分压相关,r=0993,P<0001。结论照射过程中移植瘤氧分压呈下降趋势,放疗后数分钟仍然持续下降。

Objective To study the oxygen tension change in xenograft tumor of human cervical cancer during irradiation. Methods We injected 0.2 ml solution of HeLa cell suspension intradermally at the lateral side of right hindlimb of each nude mouse. When the tumor size exceeded 1.5 cm, the partial tension of oxygen(PO-2) in the tumor and normal tissue was measured and the tumor as well as normal tissue of hindlimb were irradiated with 10 MeV electron beam (SSD=96 cm, dose rate =100 cGy/min, total dose=400 cGy). The partial tension was measured before irradiation and every 30 seconds from the beginning of irradiation until 4 minutes after irradiation. Results 1.Eight nude mice were used in this experiment, and 7 of them survived. Altogether 7 tumors were formed, so the rate of successful tnmor growth was 87.5%(7/8). The mean size of the tumor was (1.7585±0.2020) cm. 2. The mean PO_2 in the tumor was (3.3857±0.6694) kPa, indicating obvious hypoxia,whereas the PO-2 in the normal hindlimb was (11.7714±2.2787) kPa (t=7.678,P<0.01). 3. The PO_2 in normal tissue during irradiation was not related with the time of irradiation (r=0.029, P=0.940) but the decrease of PO-2 in tumor during irradiation was related with the irradiation time (r=0.927, P<0.001). The PO_2 in normal tissue after irradiation was not related with the time of irradiation (r=0.446, P=0.229),while the decrease of PO-2 in tumor after irradiation was (r=0.946, P<0.001). 4. The PO_2 in the tumor the after the irradiation was related with PO-2 before the irradiation (r=0.993, P<0.001). Conclusion The PO_2 in xenograft tumor declines gradually during irradiation and this trend lasts for a few minutes after irradiation.;