甲状腺激素对成年大鼠额叶内synaptotagmin 1及SNAP-25表达的影响

目的观察成年期甲状腺功能减退症(简称甲减)大鼠额叶内突触结合蛋白1(Syt-1)及突触相关蛋白SNAP-25(synaptosomal associated protein of 25KD)的改变及左旋甲状腺素(T4)替代治疗后的恢复状况,探讨甲减脑损伤及恢复可能的分子机制。方法药物建立成年期大鼠甲减及治疗模型,放射免疫法测定血清甲状腺激素水平,Western blot法观察Syt-1和SNAP-25在大鼠额叶的表达。结果与对照组相比,甲减组大鼠血清T3、T4水平显著降低(P<0.05),额叶突触小体内Syt-1的表达水平显著低于对照组,SNAP-25的表达水平显著高于对照组(P<0.05);T4替代治疗组与对照组比较血清T3、T4无统计学差异;Syt-1及SNAP-25的表达无统计学差异(P>0.05)。结论成年期甲减大鼠额叶内Syt-1表达减少,SNAP-25表达增加,甲状腺素治疗能使其恢复。

The regulation of thyroid hormone on synaptotagmin-1 and SNAP-25 expression in the prefrontal cortex ofrats with adult-onset hypothyroidism

Objective To observe the effect of adult-onset hypothyroidism on the expression of Syt-1 and SNAP-25 in the prefrontal cortex of adult rats and learn the effect of Levothyroxin（L-T4） treatment. Methods In a- dult rats adult-onset hypothyroidism was induced with propylthiouracil （PTU）, and the levels of Syt-1 and SNAP-25 in the prefrontal cortex were assayed using Western blotting. Results Our data showed that serum 13,T4 levels were significantly lower in the hypothyroid group rats than those in the control group rats （ P 〈 0.05 ） ; the levels of Syt-1 protein were significantly decreased in the crude synaptosome of prefrontal cortex compared to the control group;the levels of SNAP-25 protein were significantly increased in the crude synaptosome of prefrontal cortex compared to the control group （ P 〈 0.05 ）. After L-T4 treatment, the levels of serum 33, T4 returned to the normal, and there were no significant difference on Syt-1 and SNAP-25 protein levels after L-T4 treatment （P 〉 0.05 ）. Conclusion L-T4 could reverse these alterations,the decreased Syt-1 expression and increased SNAP-25 expression in the prefrontal cortex in the adult-onset rats with hypothyroidism.