Preventive effects of probiotic bacteria Lactobacillus plantarum and dietary fiber in chemically-induced mammary carcinogenesis.

AIM: The purpose of the present study was to evaluate the chemopreventive efficacy of a new probiotic bacterial strain, Lactobacillus plantarum LS/07 (PRO), prebiotic oligofructose-enriched inulin (PRE) and PRO-PRE combination in a rat model of breast cancer. MATERIALS AND METHODS: Mammary carcinogenesis was induced by 7,12-dimethylbenz[a]anthracene (DMBA). Daily oral administration of PRO (at a dose of 8.4×10(8) c.f.u./rat) and PRE (in the diet, 20 g/kg) started two weeks before the first DMBA dose and lasted until the end of the experiment (16 weeks). RESULTS: Administration of PRO, PRE and PRO-PRE combination significantly suppressed the tumor frequency, increased Cd4(+) T-cells in tumor tissue and reduced serum tumor necrosis factor-α concentration. In PRO and PRO-PRE groups, the decline of Cd8(+) T-cells in blood and their increase in tumor tissue was observed. CONCLUSION: Long-term administration of Lactobacillus plantarum LS/07 with and without inulin is effective against breast cancer, at least partially, through immunomodulatory mechanisms.