牛磺酸对高胆固醇血症小鼠胆固醇／胆汁酸吸收与排出的影响

Effect of taurine on absorption and excretion of cholesterol/bile acids in hypercholesterolemic mice

为探讨牛磺酸对高胆固醇血症小鼠胆固醇/胆汁酸代谢的影响,本文以10周龄雄性C57BL/6小鼠为实验对象,根据体重和血清胆固醇水平随机分为6组,对照组(N)、高胆固醇膳食组(C)、高胆固醇/胆盐膳食组(CB)以及分别与这三组相对应的牛磺酸添加组(NT、CT、CBT)。给与各组相应膳食1周后,测定血清和肝脏胆固醇含量,粪胆汁酸和中性固醇含量,以及胆固醇/胆汁酸稳态相关因子肝脏ABCG5/ABCG8、BSEP,空肠ABCG5/ABCG8,回肠BABP、BAT mRNA表达。结果显示:分别与C、CB组相比较,CT、CBT组小鼠血清和肝脏胆固醇显著降低(P<0·05)、粪胆汁酸量明显增加(P<0·05)、粪中性固醇量无显著变化;与N组相比较,C/CT/CB/CBT四组小鼠肝脏ABCG5/ABCG8、BSEP,空肠ABCG5/ABCG8mRNA表达增加,但四组间无显著差异;与N组相比较,C/CT/CB/CBT四组小鼠回肠BAT mRNA表达明显减少,CT组比C组进一步降低。以上结果提示,牛磺酸增加了高胆固醇血症小鼠粪胆汁酸的排出,并不影响粪中性固醇的排出,并且在无外源性胆盐的条件下显示抑制回肠BAT mRNA表达的倾向。

In order to examine the effect of taurine on metabolism of cholesterol and bile acids,10-weeks-old male C57BL/6 mice were divided into 6 groups：control group （N）,high cholesterol diet group （C）,high cholesterol and cholate diet group （ CB）, and their 1 % taurine-supplemented groups （ NT, CT, CBT, respectively） based on their serum cholesterol levels and body weights.After mice were fed with the respective diets for a week,following indexes were determined： the level of serum and liver cholesterol, fecal bile acids and neutral sterol, mRNA expression of factors involved in cholesterol/bile acids homeostasis （liver ABCG5/ABCG8 and BSEP, jejunum ABCG5/ABCG8,ileum BABP and BAT）.The results showed：compared to that of C and CB group respectively, serum and liver cholesterol concentrations in CT and CBT groups were significantly decreased,fecal bile acids level was markedly increased,and no difference in fecal neutral sterol level.The mRNA levels of liver ABCG5/ABCG8 and BSEP,and jejunum ABCG5/ABCG8 were significantly increased in C/CT/CB/CBT groups compared to that in N group,but there was no difference in four groups. 1-BAT mRNA level notably reduced in C/CT/CB/CBT groups compared to that in N group,and the decreased tendency was observed in CT group compared to C group.The above results suggested taurine enhanced fecal bile acids excretion but not affected fecal neutral sterol excretion, and tended to decrease ileum BAT gene expression by high cholesterol diet without exogenous cholate in mice.