抄録
The effect of oral administration of viable Lactobacillus casei strain Shirota (LcS) on prevention of azoxymethane (AOM) -induced intestinal tumors in the rat was investigated. Thirty rats each received a weekly subcutaneous injection of AOM at a dose of 7.4mg/kg body weight for 10 weeks. Twenty-five weeks after the start of the carcinogen treatment, all rats were sacrificed, and the total intestine and the mesenteric lymph nodes (MLN) were removed. The incidence of tumors and lymphocyte surface markers derived from the MLN were investigated. The incidence of colon cancer was significantly lower in the rats which had consumed the LcS diet compared to the controls. The number of lymphocytes and CD8-positive lymphocytes was significantly higher in the rats given the LcS diet. LcS may therefore effectively inhibit chemically-induced colon carcinogenesis in the rat. CD8-positive T lymphocytes may play a key role in this protective effect against colon carcinogenesis.
