低剂量照射对小鼠S180肉瘤组织CyclinE和PCNA表达影响

目的探讨低剂量照射对小鼠S180肉瘤组织细胞周期蛋白E（CyclinE）和增殖细胞核抗原（PCNA）表达的影响。方法昆明种雄性小鼠右后肢腹股沟皮下接种S180肉瘤细胞，随机分成对照组（假照组）、照射组。接种后1周以75mGy的γ射线全身照射照射组小鼠，于照射后12、24、48及72h处死两组小鼠，直接测量肿瘤直径，取瘤组织用PV二步法半定量检测CyclinE、PCNA表达情况。结果与假照组相比，75mGy的7射线全身照射后小鼠肿瘤生长缓慢（t=2．19，P〈0．05）。低剂量照射后各组小鼠CyctinE表达与假照组比较差异无显著性（P〉0．05）；照射后48h小鼠瘤组织PCNA表达较假照组明显下降（u=2．34，P〈0．05）。结论低剂量照射可降低CyclinE、PCNA的表达，从而抑制肿瘤生长，对低剂量照射抗肿瘤机制的研究有一定的指导意义。

EFFECTS OF LOW DOSE RADIATION ON CycUn E AND PCNA EXPRESSION IN MICE WITH S180 SARCOMA

Objective To study the effects of low dose radiation （LDR） on the expressions of cell cycle protein E （Cyclin E） and proliferating cell nuclear antigen （PCNA） in mice with S180 sarcoma. Methods S180 sarcoma ceils were inoculated into subcutaneous tissue of the right hind inguinal area in Kunming male mice. One week after inoculation, the mice were randomly divided into two groups： the radiation group and control group （sham radiation）. The radiation group received 75 mGy whole-body yirradiation. All mice were sacrificed at 12, 24, 48 and 72 h after irradiation. The tumor diameter was measured and the expression of Cyclin E and PCNA detected by P-V immunohistochemistry technique. Results Compared with the control group,the tumor growth in the radiation group was significantly slowed down after LDR （t=2.19, P〈0.05）. There was no significant difference in Cyclin E expression between the two groups （P〉0.05）. Forty-eight hours after LDR, the PCNA expression in the radiation group was significantly lower than that of the control （u=2.34,P〈0.05）. Conclusion LDR can reduce the expressions of cell-cycle related proteins PCNA and Cyclin E, and inhibit tumor growth. The results of the present study provide useful information for further study on the anti-tumor mechanism of LDR.