碘过量对仔鼠脑突触素表达影响及硒干预作用

目的 研究碘过量摄入对小鼠仔鼠脑突触素表达影响及硒的干预作用.方法 将60只BALB/c小鼠随机分为4组:正常对照组(饮用自来水)、碘(Ⅰ)过量组(饮水3 000μg/L Ⅰ)、单独补硒(Se)组(饮水200μg/L Se)、碘过量加硒(饮水3 000 μg/L Ⅰ+200μg/L Se)组.饲养4个月后,雌雄交配.测定第14和28 d仔鼠血清总四碘甲状腺原氨酸(T_4)和总三碘甲状腺原氨酸(T_3)水平,分别用荧光定量聚合酶链式反应(PCR)和蛋白印迹试验(Western blot)测定仔鼠大脑组织突触素mRNA和蛋白的表达.结果 第14 d碘过量组仔鼠血清L_4水平为(68.78±11.10)nmol/L,明显低于正常对照组和碘过量加硒组的(100.85±11.47)和(93.15±12.10)nmol/L(P<0.05);其脑组织突触素mRNA相对量为(44.87±3.82),明显低于正常对照组、单独补硒组和碘过量加硒组的(58.34±8.13),(54.33±5.32),(49.89±7.46);其蛋白相对量为(0.64±0.02),明显低于正常对照组、单独补硒组和碘过量加硒组的(0.78±0.01),(0.76±0.01),(0.81±0.03)(P<0.05).碘过量和补硒对第28 d仔鼠血清T_4和T_3水平和脑组织突触素表达水平无明显影响.结论 碘过量引起仔鼠脑突触素表达异常,补硒有缓解作用.

Intervention of selenium on synaptophysin expression in cerebrum of filial mice with excess iodine

Objective To study effects of excess iodine intake on synaptophysin expression in the cerebrum of filial mice aad the intervention of selenium. Methods Sixty BALB/c mice were divided randomly into four groups with different drinking water:control group (tap water), excess iodine group (3 000 μg/L), supplementing selenium group (200 μg/L)and excess iodine plus selenium (3000 μg/L of iodine + 1 200 μg/L of selenium) group. The mice were mated at the end of the fourth month. Serum T_4 and T_3 were determined on 14th and 28th posmatal day. The expression level of synaptophysin in filial cerebrum was measured with fluorescent real time PCR and Western blot. Results Serum T_4 level in excess iodine group(68.78 ± 11.10 nmol/ L) was lower significantly than that of in control group (100.85 ± 11.47 nmol/ L) and excess iodine plus selenium group (93.15 ± 12.10 nmol/ L) on 14th posmatal day. mRNA and protein level of synaptophysin in excess iodine group(relative mRNA and protein level was 44.87 ± 3.82 and 0. 64 ± 0.02) was lower than that in other groups (relative mRNA level was 58.34 ± 8. 13,54.33 ± 5.32,49. 89 ± 7.46, relative protein level was 0. 78 ± 0. 01, 0.76 ± 0.01,0.81 ± 0.03, respectively) on 14th postnatal day(P < 0.05). No significant difference was observed in serum T4 and level of synaptophysin between four groups on 28th postnatal day. Conclusion Excess iodine intake can change the expression of synaptophysin in cerebrum and selenium of filial mice and selenium supplementation can alleviate it.