甲状腺激素对大鼠额叶乙酰胆碱的影响

目的研究成年期甲状腺功能减退症大鼠额叶内乙酰胆碱变化及甲状腺素替代治疗后的情况。方法 26只成年期雄性SD大鼠随机分为三组,用丙基硫氧嘧啶(PTU)建立成年期大鼠甲减模型,采用放射免疫法测定健康对照组、甲减组、甲状腺素替代治疗组(T4-6)大鼠的血清甲状腺激素水平;碱性羟胺比色法测定脑组织乙酰胆碱含量;用单因素方差分析比较三组之间各项指标差异。结果与健康对照组相比,甲减组大鼠血清T3、T4水平显著减低、TSH水平增加(P<0.05);替代治疗后,血清T3、T4、TSH恢复至正常水平;甲减组大鼠额叶内乙酰胆碱含量降低(P<0.05),替代治疗后乙酰胆碱含量与对照组相比差异无统计学意义(P>0.05)。结论成年期甲减大鼠额叶内乙酰胆碱含量减少,甲状腺素替代治疗后乙酰胆碱含量恢复正常。

Effect of thyroxine on acetylcholine level in the prefrontal cortex of rats with adult-onset hypothyroidism

Objective To study acetylcholine（ACh） level in prefrontal cortex of adult-onset hypothyroidism rats,and the difference of Ach after thyroid hormones treatment. Methods This animal study included control group （n = 9）, Hypothyroidism group （n = 8 ） and Hypothyroidism treated with T4 （6μg/100g body weight） group （n = 9）. The hypothyroidism models were replicated with 6-n-propyl-2-thiouracil （PTU）. The levels of serum T3, T4 were assayed by radioimmunoassay method , and the level of acetylcholine （ACh） in prefrontal cortex was analyzed by the basic hydroxylamine colorimetric method. Results Compared to the control group, serum levels of T3 and T4 were significantly lower in the hypothyroid group （ P 〈 0.05 ） and similar in the T4-6 group and brain ACh level were significandy lower in prefrontal cortex in the hypothyroid than those of the control group （ P 〈 0.05 ） and were not significandy different in the T4-6 group. Conclusion The level of Ach in the prefrontal cortex of aduh-onset hypothyroidism is lower, Ach may be reversed by thyroid hormones replasement treatment in T4-6 group.