吲哚-3-甲醇对荷鼻咽癌裸鼠肿瘤转归及抗氧化体系的影响

目的 探讨吲哚-3-甲醇(indole-3-carbinol,I3C)对荷鼻咽癌裸鼠肿瘤转归及抗氧化体系的影响.方法 采用随机数字表法将48只BALB/c裸小鼠分为I3C低(0.02 g/kg)、中(0.1 g/kg)、高(0.5 g/kg)剂量组和溶剂对照组(体积分数为0.5%的羧甲基纤维素钠溶液),分别经口灌胃给予实验动物相应剂量的I3C或对照溶液10 d后,于其背部靠腋窝皮下接种人鼻咽癌细胞株CNE1,继续经口灌胃给予实验动物相应剂量的I3C或对照溶液.实验第31天时处死动物,测量肿瘤体积、计算抑瘤率,并留取肿瘤组织进行丙二醛(malondialdehyde,MDA)含量、超氧化物歧化酶(superoxide dismutases,SOD)和谷胱甘肽过氧化物酶(glutathione peroxidase,GSHPx)活力测定及活化型半胱天冬酶-3(cleaved caspase-3)表达检测.结果 I3C各剂量可不同程度地抑制肿瘤生长,与对照组(4.13±0.53)×10~(-6)m~3]相比,中、高剂量组(3.14±0.71)×10~(-6)m~3、(2.72±0.29)×10~(-6)m~3]肿瘤体积缩小的差异具有统计学意义(t值分别为0.990和1.510,P值均<0.01);低、中、高剂量I3C的抑瘤率分别为3.8%、20.5%和34.9%;肿瘤组织MDA含量随I3C剂量的增加逐渐降低对照组及低、中、高3个剂量组动物肿瘤组织MDA含量分别为(31.29±2.51)×10~(-6)mol/L、(30.12±2.37)×10~(-6)moL/L、(23.32±1.93)×10~(-6)mol/L、(16.45±1.43)×10~(-6)>mol/L](F=98.752,P<0.01),与对照组比较,中、高剂量组动物肿瘤组织MDA含量降低具有统计学意义(t值分别为8.970和14.840,P值均<0.01);I3C各剂量可不同程度地提升肿瘤组织SOD活力,对照组及低、中、高3个剂量组动物肿瘤组织SOD活力分别为(387.24±23.16)×10~3U/L、(399.37±34.45)×10~3U/L、(431.63±31.24)×10~3U/L、(476.45±44.67)×10~3U/L(F=53.444,P<0.01),与对照组比较,中、高剂量组动物肿瘤组织SOD活力的升高具有统计学意义(t值分别为44.390和89.210,P值均<0.01);肿瘤组织GSHPx活力随I3C剂量的增加而逐渐增强对照组及低、中、高3个剂量组动物肿瘤组织GSHPx活力分别为(226.98±18.35)×10~3U/L、(234.65±15.59)×10~3U/L、(247.72±22.73)×10~3U/L、(300.37±26.02)×10~3U/L](F=25.916,P<0.01),与对照组比较,高剂量组动物肿瘤组织GSHPx活力明显升高(t=73.390,P<0.01).相对分子质量为19 000 000的cleavedcaspase-3蛋白表达随染毒剂量的增加逐渐增强(F=39.864,P<0.01),对照组及低、中、高剂量组蛋白表达的相对水平分别为0.87±0.01、0.97±0.01、1.02±0.06和1.14±0.02,与对照组相比,其表达的增强在3个I3C剂量组均具有统计学意义(t值分别为0.100、0.086和0.303,P值均<0.05).相对分子质量为17 000 000的cleaved caspase-3蛋白表达随染毒剂量的增加亦逐渐增强(F=56.629,P<0.01),对照组及低、中、高剂量组蛋白表达的相对水平分别为0.00±0.00、0.05±0.02、0.11±0.02、0.20±0.02,与对照组相比,3个I3C剂量组中其表达的增强均具有统计学意义(t值分别为0.046、0.103和0.193,P值均<0.05).相关分析结果表明肿瘤体积的缩小与两种cleaved caspase-3蛋白表达增加之间的Pearson相关系数r分别为-0.732(t=3.404,P<0.01)和-0.901(t=6.642,P<0.01).结论 I3C可抑制肿瘤生长,其机制可能与通过降低MDA含量,提高SOD及GSHPx活力等途径降低氧化应激程度及通过caspase-3信号分子诱导凋亡的作用相关.

Effects of indole-3-carbinol on the outcome of tumor and the changes of anti-oxidative system in null mice grafted with nasopharyngeal carcinoma

Objective To observe the effects of indole-3-carbinol (I3C) on the outcome of the tumor as well as the changes of the anti-oxidative system in null mice grafted with nasopharyngeal carcinoma. Methods 48 BALB/c null mice were divided by means of random number table into control group (0. 5% sodium carboxyl methyl cellulose),low dosage (0.02 g/kg),middle dosage (0. 1 g/kg) and high dosage(0. 5 g/kg) of I3C. The mice were administered with different solutions by gavage for 10 days before CNEI cells were inoculated subcutaneously into the back (near the armpit) of the nude mice,then the solutions were continually administered by gavage. The tumor volume was measured and the tumor inhibitory rate was calculated. The level of malondialdehyde (MDA),the activity of superoxide dismutases (SOD),the activity of glutathione peroxidase (GSHPx) and the expression of cleaved caspase-3 were determined on the 31th day of the study. Results I3C could reduce the tumor volume the tumor volumes of the control group,the middle dosage group and the high dosage group were(4. 13±0. 53)×10~(-6)m~3, (3.14±0.71)×10(-6)m~3, (2. 72±0. 29)×10~(-6)m~3], as compared with the control, the shrinkage of tumor volume of the middle dosage group and the high dosage group were significant (the t valued at 0. 990 and 1.510, P< 0.01). The tumor inhibitory rates of 3 groups were 3.8%,20.5% and 34.9%,respectively. The contents of MDA in the tumor tissue tended to decrease the values of control group,the low dosage group,the middle dosage group and the high dosage group were(31.29±2. 51)×10~(-6)mol/L, (30. 12±2. 37)×10~(-6) mol/ L, (23. 32±1.93)×10~(-6) mol/L, (16.45±1.43)×10~(-6) mol/L](F=98. 752, P < 0. 01), and that of the high and the middle dosage group could obviously be reduced (t=8. 970,14. 840, P < 0.01) as compared with the control. The activity of SOD seemed to be elevated according to the increase of I3C dosage the values were (387.24±23.16)×10~3 U/L, (399. 37±34. 45)×10~3 U/L, (431.63±31.24)×10~3 U/L, (476.45±44. 67)×10~3 U/L](F=53.444,P < 0. 01). When compared with the control, the SOD activity of the middle and the high dosage group be obviously increased (t=44. 390,89. 210,P <0.01). I3C could also elevate the GSHPx activity the GSHPx values of the four groups were (226. 98±18.35)×10~3 U/L, (234.65±15.59)×10~3 U/L, (247.72±22. 73)×10~3 U/L, (300. 37±26. 02)×10~3 U/L](F=25.916,P < 0. 01). The GSHPx of the high dosage group was enhanced remarkable(t=73. 390, P < 0. 01) as compared with the control. The expression of cleaved caspase-3 (relative molecular weight=19 000 000) seemed to be elevated according to the increase of I3C dosage and the relative expression levels of wbich were 0. 87±0. 01,0. 97±0. 01,1.02±0. 06 and 1.14±0.02 (F=39. 864, P < 0. 01). When compared with the eontrol,the elevation of this kind of cleaved easpase-3 was considered statistical significant (the t values were 0. 100,0. 086 and 0. 303, respectively, P < 0. 05). When 13C dosage increased, the expression of cleaved caspase-3 (relative molecular weight=17 000 000) seemed to increased too the relative expression levels of which were 0.00±0.00,0.05±0.02,0. 11±0.02,0.20±0.02(F=56.629,P<0.01)],and the increase of this kind of cleaved caspase-3 was esteemed significantly as compared with those of the control (the t valued at 0. 046,0. 103 and 0. 193, respectively, P < 0. 05). Linear correlate analysis showed that the correlation coefficients between the shrinkage of tumor volume and the expression of the two kinds of cleaved caspase-3 protein was-0.732 (t=3. 404, P < 0. 01) and-0. 901 (t=6. 642, P < 0. 01). Conclusion I3C could reduce the growth of tumor, the mechanism underlie it could be related to the decrease of the content of MDA as well as the elevated levels of SOD,GSHPx,and perhaps could be related to the apoptosis transducted by cleaved caspase-3.