早期饲料构成对大鼠甲状腺素及肉碱棕榈酰转移酶-ⅠmRNA表达的影响

目的:研究早期饲料构成对高脂膳食大鼠体重、体脂含量、血糖、甲状腺素FT4及肝脏肉碱棕榈酰转移酶-Ⅰ(CPT-Ⅰ)mRNA水平的影响。方法:新生Wistar雄性大鼠24d断乳,按体重随机分为A、B、C、D四组,分别给予高碳水化合物构成的基础饲料、高蛋白质、高不饱和脂肪酸、与高饱和脂肪酸构成的饲料喂养3w后,基础饲料喂养2w。按体重将A组随机分为A1、A2两组。A1组喂饲基础饲料作为对照组,A2与B、C、D组给予高脂饲料喂养6w,结束实验;A2组为高碳水化合物对照组。每组32头大鼠,动态观察体重、体脂含量、血糖、甲状腺素(FT4)及肝脏CPT-ⅠmRNA水平。结果:实验末期,C组大鼠体重、体脂含量和血糖显著低于A2组(P<0.05)、甲状腺素FT4水平明显高于A2组(P<0.05);B组体重、体脂含量明显低于A2组(P<0.05),甲状腺素FT4水平明显高于A2组(P<0.05),但血糖水平高于A2组(P>0.05);D组大鼠体重明显低于A2组(P<0.05),血糖、体脂含量和甲状腺素FT4水平与A2无差异(P>0.05)。动态观察表明,实验中C组大鼠肝脏CPT-ⅠmRNA水平持续升高。结论:早期饲料构成可能通过影响甲状腺素水平、持续改变CPT-Ⅰ基因表达,影响高脂膳食大鼠的体重和体脂含量。

EFFECTS OF EARLY DIETARY COMPOSITIONS ON THYROXINE AND CARNITINE PALMITYL TRANSFERASE-Ⅰ GENE EXPRESSION IN RATS

Objective:To study the effects of early dietary compositions on body weight, body fat content, free thyroid hormoneT4(FT4)and carnitine palmityl transferase-Ⅰ(CPT-Ⅰ) gene expression in rats. Method:Male Wistar rats weaned on 24 d were randomly divided into A, B,C,D groups and were fed carbohydrate (basic), high protein, high unsaturated fatty acid and high saturated fatty acid diet respectively. After 3w, all rats were assigned to basic diet for 2w, and then rats from A group were randomly divided into groups A1 and A2. A1 was fed on basic diet continuously. Groups A2 ,B,C,D were assigned to high-fat diet for 6w. Body weight, body fat, blood glucose and FT4 ,and CPT-ⅠmRNA were observed in eight rats of every group. Results:Body weight, body fat and FT4 level in C group were significantly lower than those in A2 on 11w(P<0.05).The body weight, body fat were lower, but FT4 level and blood glucose were higher in B group significantly than those in A2(P<0.05). The body weight was lower in D group significantly than that in A2, but body fat , blood glucose and FT4 were not different from those in A2 significantly. The CPT-ⅠmRNA level in C group was persistently increased during experiment. Conclusion:Early feeding of high unsaturated fatty acid diet in rats may significantly reduce the body weight, body fat content and inhibit obesity incidence by higher free thyroid hormone ,through increase of CPT-Ⅰgene expression.