单一剂量美法仑治愈荷瘤C57BL/6小鼠动物模型的建立

Establishment of an animal model for EL4 tumor-bearing mice cured by a single dose of melphalan

[目的]建立单一剂量化疗药物治愈荷瘤小鼠的动物模型,为研究在体内化疗药物治愈肿瘤与机体免疫力和肿瘤细胞耐药之间的关系奠定基础。[方法]用MTT法在体外检测小鼠淋巴瘤EL4细胞对化疗药物美法仑的敏感性。野生型C57BL/6小鼠皮下接种小鼠淋巴瘤EL4细胞建立荷瘤小鼠模型,不同剂量的美法仑单次腹腔内注射,观察不同剂量的美法仑体内治疗的效果及其毒、副作用,找出美法仑可发挥最大抑瘤作用、并能使荷瘤小鼠的肿瘤消退、不再复发的最小治疗剂量。[结果]体外美法仑对EL4细胞的直接杀伤作用与所用美法仑的剂量呈正相关。接种1×105EL4细胞可使C57BL/6小鼠肿瘤进行性生长,接种后12 d平均肿瘤直径为6 mm,动物致死时间平均为(17.7±1.0)d。接种后12 d的荷瘤小鼠腹腔单次注射不同剂量的美法仑,观察发现:应用0.75 mg/kg^30 mg/kg的美法仑,肿瘤结节缩小的速率与所用美法仑的治疗剂量呈正相关;在肿瘤结节完全消退后,肿瘤的复发率与所用美法仑的治疗剂量呈负相关。7.5 mg/kg美法仑单次腹腔内注射后不但使野生型C57BL/6荷瘤小鼠的肿瘤完全消退,治疗后2个月内无肿瘤复发,并且再次接种等量肿瘤细胞无肿瘤生长。[结论]单一剂量(7.5 mg/kg)的美法仑腹腔内注射是可以治愈野生型C57BL/6荷瘤小鼠的最低有效剂量。该动物模型的建立为研究化疗药物治愈恶性肿瘤的机制奠定了基础。

[ Objective] To establish a tumor model cured by a single dose of melphalan in wild type C57BL/6 tumor- bearing mice. [ Methods ] The sensitivity of mouse lymphoma EL4 cells to melphalan was measured by using MTT assay. Mouse lymphoma EL4 cells were inoculated subcutaneously into wild type C57BL/6 mice. 12 days later, different doses of melphalan were used intraperitoneally to treat these tuomr - bearing mice. Treatment and side effects were observed and recorded subsequently. The lowest dose of melphalan that could cure the tumor - bearing mice was discovered. [ Results] Melphalan could kill EL4 tumor cells directly in a dose - dependent way. Inoculation of 1×10^5 EL4 cells could make tumor cell progressive growth in C57BL/6 mice. The tumor sizes were about 6 mm on day 12 after tumor cell inoculation. All the mice were treated with different doses （0 - 30 mg/kg） of melphalan intraperitoneally. The speed of tumor shrinkage had a positive relationship with the dose of melphalan used; however, the relapse rate of tumor after tumor complete regression was in a negative way. All the mice that received a single dose of melphalan （7.5 mg/kg） showed tumor shrinkage and complete tumor regression within 7 days. No tumor relapse during the following 60 days, and no tumor grow after the same amount of EL4 cells reinoculation. [ Conclusions] The animal model cured by 7.5 mg/kg melphalan intraperitoneally in wild type C57BL/6 mice had established successfully.