Cancer preventive effects of a specific probiotic fermented milk containing Lactobacillus acidophilus CL1285, L. casei LBC80R and L. rhamnosus CLR2 on male F344 rats treated with 1,2-dimethylhydrazine.
Résumé
The effect of fermented milk (FM) consisting of three probiotic strains (Lactobacillus acidophilus CL1285, L. casei LBC80R and L. rhamnosus CLR2) on colon cancer prevention in rats treated with dimethylhydrazine (DMH) was investigated. The rats were divided into 7 groups of 8 animals. Rats were fed with a high fat low fibre diet; group 1 was a negative control, while groups 2 to 7 were injected with DMH (30 mg/kg s.c.) once a week for six weeks. Groups 3 to 7 were gavaged respectively with 2, 1.5, 1, 0.5 and 0.25 ml of FM every day. After 12 weeks, the rats were sacrificed and the colon, caecum and liver were collected. Aberrant crypt foci (ACF) in the colon were determined using a microscope. Detoxifying enzymes like quinone reductase (QR) and glutathione-S-transferase (GST) and faecal enzymes such as β-glucosidase and β-glucuronidase were evaluated by spectrophotometry. The rats fed with the three highest doses significantly lowered aberrant crypt (AC) count, while those supplemented with 1.5 and 2 ml FM lowered significantly ACF count compared to group 2 (p ≤ 0.05). Rats fed with the highest doses significantly induced GST activity, while only rats fed with 2 ml reduced significantly β-glucuronidase activity compared to group 2 (p ≤ 0.05). These results indicate that the FM could have a potential role in colorectal cancer prevention.