弓形虫Prugniaud株诱导的对小鼠黑色素瘤抑制作用的体内实验研究

Inhibitory effect to mice malignant melanoma induced by infecting Prugniaud strain of Toxoplasma gondii

目的探讨弓形虫Prugniaud实验感染增强宿主的非特异性抗肿瘤效应,检测Prugniaud株单独感染或联合卡介苗(BCG)对小鼠恶性黑色素瘤的抑制作用。方法体内实验用绿色荧光标记的转基因小鼠每组9只,荷瘤后单独感染弓形虫Prugniaud株或联合BCG,比较肿瘤生长情况,计算抑瘤率,并用流式细胞仪检测各组小鼠肿瘤细胞的凋亡率。RT-PCR检测肿瘤组织中VEGF的mRNA的表达水平。结果 B16组、BCG/B16组、TG/B16组、TG/BCG/B16组小鼠瘤重分别为3.237±0.552g、2.461±0.320g、1.521±0.263g、1.069±0.444g,各组肿瘤凋亡率分别为7.42±2.09%、9.27±2.10%、23.32±4.37%、43.88±6.33%;光镜下TG/B16组和TG/BCG/B16组小鼠能明显抑制肿瘤细胞生长,并且VEGF120/β-actin和VEGF120/β-actin低于其他组(TG/B16:0.167±0.011,0.190±0.015);TG/BCG/B16:0.140±0.015,0.171±0.011)。结论弓形虫感染对小鼠黑色素瘤有抑制作用,降低血管内皮生长因子mRNA表达量,并且在BCG联合作用下效果得到增强。

Objective To explore the non-specific anti-tumor activity induced by infecting Prugniaud strain of T.gondii (TG), and to detect the inhibitory effect to mice malignant melanoma induced by infecting TG alone or in combination with BCG. Methods The transgenic mice labeled with green fluorescent protein were selected, each group contained 9 mice. After bearing malignant melanoma, the mice were infected with TG alone or in combination with BCG, then the growth of the tumor were compared, the inhibitory rate of the tumor were calculated, the apoptosis rate of the tumor cells were detected by flow cytometer assay, and the expression level of VEGF mRNA in the tumor were detected by RT-PCR. Results The average tumor weight in group B16, group BCG/B16, group TG/B16 and group TG/BCG/B16 was 3.237±0.552g, 2.461±0.320g, 1.521±0.263g and 1.069±0.444g, respectively, the apoptosis rate in 4 groups was 7.42±2.09%, 9.27± 2.10%, 23.32±4.37% and 43.88±6.33%, respectively. The tumor cell growth inhibition in group TG/B16 and group TG/BCG/B16 was observed under microscope, and the VEGF120/β-actin and VEGF120/β-actin in two groups were significantly lower than that of other gronps(group TG/B16:0.167±0.011 and 0.190±0.015; group TG/BCG/B16: 0.140±0.015 and 0.171 ±0.011). Conclusion TG inhibits the proliferation of malignant melanoma cells in mice, and decreases the expression quantity of VEGF mRNA, these anti-tumor effects are significantly enhanced by the addition of BCG.