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In vitro binding of the carcinogen N-[methyl-^<14>C]-nitrosodimethylamine by algal dietary fibers and their role in reducing its bioaccumulation.

致癌物N-[甲基-14C]-亚硝基二甲胺与藻类膳食纤维的体外结合及其在减少其生物累积中的作用。

基本信息

批准号：
04671397
负责人：
YAMAMOTO Ichiro
金额：
$ 1.34万
依托单位：
Kitasato University School of Hygienic Sciences
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

The first study was initiated to determine if algal dietary fibers (DF) bind the carcinogen N-[methyl-^<14>C]-nitrosodimethylamine ([^<14>C]-DMNA) in vitro and how bioaccumulation of orally-given carcinogen is affected by a diet containing algal DF.Eight kineds of algal DF, including powdered fronds of Laminaria religiosa (LRP) and agar (from Gracilaria verrucosa) were used in the in vitro test. Cellulose powder (CP) was used as a control DF.In vitro binding rates of DMNA by CP, LRP and agar were 0.28%, 0.65% and 0.21% of the initial dose, respectively. Rats fed a diet containing 2% LRP or 2% agar were examined at 3 h or 24 h after dosing. There was reduced retention of the orally-ingested DMNA in the liver, posibly because of reduced DMNA-adsorption from the intestinal tract earlier than 3 h after dosing. Binding rates of DMNA by algae were neither related to the DF values nor to the extent of reduction of DMNA-absorption from the intestinal tract.The second study was performed to verify the effects of cellulose (nsoluble in water) and of polydextrose (soluble in water), in reducing bioaccumulation of the carcinogen [^<14>C]-DMNA in the same in vivo experimental system, using mice. As the results, [^<14>C]-bioaccumelation in CP-fed mice remarkably reduced at 1 h after dosing, compared with that in control mice.In the time points later than 1 h after dosing, difference in the bioaccumulation between CP-fed mice and cntrols were decreased sowly as the time lapsed. The results suggest that absorption and metabolism of the carcinogen took lace within 1 h after dosing. As to polydextrosefed mice, there was no significant reductin of [^<14>C] uptake, except blood at 24 h after dosing.

第一项研究的目的是确定藻类膳食纤维 (DF) 是否在体外与致癌物 N-[甲基-^ 14 C]-亚硝基二甲胺 ([^ 14 C]-DMNA) 结合，以及含有藻类膳食纤维的饮食如何影响口服致癌物的生物蓄积。藻类膳食纤维有八种，包括粉状叶状藻类。体外测试中使用了海带 (LRP) 和琼脂（来自江蓠）。以纤维素粉(CP)作为对照DF。CP、LRP和琼脂对DMNA的体外结合率分别为初始剂量的0.28%、0.65%和0.21%。喂食含有 2% LRP 或 2% 琼脂的饮食的大鼠在给药后 3 小时或 24 小时进行检查。口服摄入的 DMNA 在肝脏中的滞留减少，可能是因为给药后 3 小时内肠道对 DMNA 的吸收减少。藻类对 DMNA 的结合率既与 DF 值无关，也与肠道 DMNA 吸收减少的程度无关。第二项研究是为了验证纤维素（不溶于水）和聚葡萄糖（溶于水）在同一体内实验中减少致癌物 [^14C]-DMNA 生物累积的作用。系统，使用鼠标。结果，与对照小鼠相比，在给药后1小时，CP喂养的小鼠中的[^ 14 C]-生物蓄积性显着降低。在给药后1小时之后的时间点，CP喂养的小鼠与对照小鼠之间的生物蓄积差异随着时间的推移而显着减小。结果表明，该致癌物在给药后1小时内就被吸收和代谢。对于聚右旋糖喂养的小鼠，除了给药后24小时的血液外，[ 14 C]摄取没有显着减少。