Bifidobacterium longum and lactulose suppress azoxymethane-induced colonic aberrant crypt foci in rats
Bifidobacterium longum and lactulose suppress azoxymethane-induced colonic aberrant crypt foci in rats
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DOI：
10.1093/carcin/18.3.517
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发表时间：
1997-03-01
期刊：
影响因子：
4.7
通讯作者：
Shackelford, L
中科院分区：
文献类型：
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作者：
Challa, A;Rao, DR;Shackelford, L
长双歧杆菌已被证明可以提供对结肠肿瘤发生的保护。乳果糖是乳糖的酮类似物，用作双歧杆菌优先生长的底物。不知道乳果糖与长双歧B沿着饲喂是否比单独饲喂长双歧杆菌具有任何优势。为了测试这种组合效果，将61只雄性Fisher 344断乳大鼠分为4组，每组15只（对照组中16只），并被分配到以下四种饮食中的一种，持续13周：（对照，C）;（ii）C + 0.5%长B（C+ B1，含有1 × 10（8）个活细胞/g饲料）;（iii）C + 2.5%乳果糖（C+L）;（iv）C + 0.5%长B + 2.5%乳果糖（C+ B1 +L）。所有动物均接受s.c.在7和8周龄时以16 mg/kg体重注射氧化偶氮甲烷，分析来自每个饮食组的10只大鼠的结肠的异常隐窝病灶（ACF），其是癌前标记物，分析来自5只大鼠的结肠粘膜和肝脏的谷胱甘肽S-转移酶（GST，II期酶标记物），结果表明，单独饲喂乳果糖和长B.longum以及两者联合饲喂可减少ACF的数量（P = 0.0001）和畸变隐窝总数显著C、C+ B1、C+L和C+ B1 +L组的活性炭纤维总数分别为187 ± 9、143 ± 9、145 ± 11和97 ± 11。B1组和L组结肠粘膜GST水平显著高于C组（P = 0.05）。乳果糖组大鼠开始出现轻度腹泻，盲肠pH值升高与ACF数量呈正相关。研究结果表明，双歧杆菌和乳果糖在大鼠结肠中具有相加的抗肿瘤作用。
Bifidobacterium longum has been shown to afford protection against colon tumorigenesis. Lactulose, a keto analog of lactose, serves as a substrate for preferential growth of Bifidobacterium, It is not known whether feeding lactulose along with B.longum will have any advantage over feeding of B.longum alone, To test this combination effect, 61 male Fisher 344 weanling rats were divided into four groups of 15 rats each (16 in the control group) and assigned to one of the following four diets for 13 weeks: (i) AIN76A (control, C); (ii)C + 0.5% B.longum (C+Bl, containing 1x10(8) viable cells/g feed); (iii) C + 2.5% lactulose (C+L); (iv)C + 0.5% B.longum + 2.5% lactulose (C+Bl+L). All animals received a s.c. injection of azoxymethane at 16 mg/kg body wt at 7 and 8 weeks of age, Colons of 10 rats from each dietary group were analyzed for aberrant crypt foci (ACF), which are preneoplastic markers, Colonic mucosa and livers from five rats were analyzed for glutathione S-transferase (GST, a Phase II enzyme marker), Results indicate that feeding of lactulose and B.longum singly and in combination reduces the number of ACF (P = 0.0001) and the total number of aberrant crypts significantly (P = 0.0005), The total number of ACF in diets C, C+Bl, C+L and C+Bl+L were 187 +/- 9, 143 +/- 9, 145 +/- 11 and 97 +/- 11 respectively, There was no significant difference in weight gain among treatments, Colonic mucosal GST levels were significantly (P = 0.05) higher in the Bl and L groups compared with group C, Initially there was a mild diarrhea in lactulose-fed rats, There was a positive correlation between higher cecal pH and number of ACF. Results of the study indicate that Bifidobacterium and lactulose exert an additive antitumorigenic effect in rat colon.