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目的考察保加利亚杆菌、嗜热链球菌、嗜酸乳杆菌等几种常用乳制品益生菌对Caco-2细胞(结肠癌细胞)增殖的影响及其联合毒性。方法活化并培养保加利亚杆菌、嗜热链球菌和嗜酸乳杆菌,分别以不同浓度的益生菌处理培养好的Caco-2细胞,用MTT比色法测定益生菌对Caco-2细胞增殖的影响,并确定3种益生菌的半数抑制浓度(IC50)。将处于同一浓度级别的3种益生菌等比混合,进行联合毒性实验,用MTT法观察它们的联合毒性作用。结果 3种益生菌在低浓度(102、103、104 CFU/ml)未显示出细胞毒性,高浓度(105、106、107、108、109 CFI/ml)显示出显著的细胞毒性作用,细胞毒性作用随着浓度增加而增强,3种益生菌的IC50分别为:保加利亚杆菌IC50=1.90×108,嗜热链球菌IC50=1.86×109,嗜酸乳杆菌IC50=1.81×109。3种益生菌对Caco-2细胞的联合毒性作用与单一益生菌的细胞毒性作用差异无统计学意义(P>0.05),经计算为独立作用。结论保加利亚杆菌、嗜热链球菌和嗜酸乳杆菌对Caco-2细胞有细胞毒性作用,且呈剂量依赖性,但3种益生菌对Caco-2细胞没有联合毒性作用。
Objective To investigate the effects of several common dairy probiotics such as Bulgarian bacillus, Streptococcus thermophilus and Lactobacillus acidophilus on the proliferation of Caco-2 cells (colon cancer cells) and their combined toxicity. Methods Activated bacillus, Streptococcus thermophilus and Lactobacillus acidophilus were cultured and activated. The cultured Caco-2 cells were treated with different concentrations of probiotics. The effects of probiotics on the proliferation of Caco-2 cells were determined by MTT assay. The half inhibitory concentration (IC50) of the three probiotics was determined. The three kinds of probiotics at the same concentration level were mixed for the joint toxicity test and the combined toxicity was observed by MTT method. Results The three probiotics did not show cytotoxicity at low concentrations (102, 103, 104 CFU / ml). High concentrations (105, 106, 107, 108, 109 CFI / ml) showed significant cytotoxicity, cytotoxicity The results showed that the IC50 values of the three probiotics were as follows: Bulgarian bacterium IC50 = 1.90 × 108, Streptococcus thermophilus IC50 = 1.86 × 109, Lactobacillus acidophilus IC50 = 1.81 × 109.3 pairs of probiotics The combined toxic effect of Caco-2 cells was not statistically different from that of single probiotics (P> 0.05), and was calculated as an independent effect. Conclusion Bacillus bulgaricus, Streptococcus thermophilus and Lactobacillus acidophilus have a cytotoxic effect on Caco-2 cells in a dose-dependent manner, but the three probiotics have no combined toxicity on Caco-2 cells.