乳酸杆菌发酵滤液中核酸抗肿瘤效应及对荷瘤鼠免疫功能的影响

The effects of nucleic acids from lactobacillus fermented filtrate on anti-tumor and immunological function in tumor-bearing mice

目的探讨乳酸杆菌DM9811培养基滤液中核酸在体外对肿瘤细胞生长及对荷瘤鼠免疫功能的影响。方法抽提乳酸杆菌DM9811对数生长期培养基滤液中核酸,进行琼脂糖电泳分析;MTT法体外观察其对于结肠癌HT-29细胞系生长的影响;动物实验观察不同组别小鼠生存期、瘤重体重比、NK细胞活性、T细胞亚群指标。结果乳酸杆菌DM9811滤液中核酸组分为RNA;在细胞浓度为1×106时,每孔加入RNA 100μg能够明显抑制结肠癌HT-29细胞系的生长;预防组荷瘤鼠除CD8＋T细胞比例之外各项指标与阴性对照组相比差异都有统计学意义（P〈0.05）,其中NK细胞杀伤活性（58.97±3.62）、CD4＋T细胞比例（27.77±5.40）和生存期（15.1±4.48）均高于阴性对照组（43.87±3.92）、（19.68±3.00）、（10.2±3.08）,瘤重体重比（0.029±0.017）低于阴性对照组（0.066±0.024）;治疗组生存期（11.8±3.12）与阴性对照组（10.2±3.08）相比差异有统计学意义（P〈0.05）,治疗组生存期长于阴性对照组。结论乳酸杆菌DM9811培养基滤液中存在核酸组分,为100200 bp的RNA片段。100μg/mL乳酸杆菌DM9811培养基滤液中RNA组分对结肠癌HT-29细胞系生长有明显抑制作用。RNA组分可以上调荷瘤鼠的细胞免疫水平,延长荷瘤鼠的生存期。

Objective To observe the effects of nucleic acids from lactobacillus DM9811 fermented filtrate on tumor cell growth and immunological function in tumor-bearing mice.Method Nucleic acids from lactobacillus DM9811 fermented filtrate treated with phenol/chloroform were analyzed by agarose gel electrophoresis.The inhibition of the nucleic acids from friltrate against colon cancer line HT-29 in vitro was detected by MTT colorimetry.This study adopted 615 mice as the objects of research.54 mice were devided into prevention group,cure group and negative control group.Survival time,tumor weight/mice weight,NK cell activity and T lymphocyte subset were used as the indexes to compare the antitumor immuntherapy effects among the three groups.Result The nucleic acids extracted from lactobacillus DM9811 fermented filtrate were RNA.The RNA molecular size was between 100 bp and 200 bp.The content of RNA had a significant positive correlation effect with bacterial content in log phase（P〈0.05）.RNA concentration at 100 μg/mL showed significant inhibition on colon cancer cell.Except CD8＋ T lymphocyte ratio all indexes of the prevention group had significant discrepancy compared with negative control group（P〈0.05）.NK cell activity（58.97±3.62）,CD4＋T lymphocyte ratio（27.77±5.40） and survival time（15.1±4.48） were all higher than negative group′s（43.87±3.92）,（19.68±3.00） and（10.2±3.08）.Tumor weight/mice weight（0.029±0.017） was lower than negative group（0.066±0.024）;Survival time（11.8±3.12） were longer than negative group（10.2±3.08）（P〈0.05）.Conclusion The nucleic acids extracted from lactobacillus DM 9811 fermented filtrate were RNA.The RNA molecular size is between 100 bp and 200 bp.RNA concentration at 100 μg/mL show significant inhibition on colon cancer cell HT-29 in vitro.Tumor-bearing mice injected with the RNA in advance can have their cell-mediated immunological function up-regulated and their survival time lengthened.