Effect of Chronic Administration of Low Dose Rapamycin on Development and Immunity in Young Rats.
Effect of Chronic Administration of Low Dose Rapamycin on Development and Immunity in Young Rats.
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长期给予小剂量雷帕霉素对幼鼠发育和免疫的影响
DOI：
10.1371/journal.pone.0135256
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Zeng LH
中科院分区：
文献类型：
--
作者：
Lu Z;Liu F;Chen L;Zhang H;Ding Y;Liu J;Wong M;Zeng LH
哺乳动物雷帕霉素靶蛋白（mTOR）调节细胞生长、细胞分化和蛋白质合成。雷帕霉素是mTOR的抑制剂，已被广泛用作免疫抑制剂和抗癌药物。最近，mTOR抑制剂也被报道是一种潜在的抗癫痫药物，用于年轻的遗传性癫痫患者可能有效。因此，应确定能够维持mTOR的正常功能并且理想地具有较少副作用的雷帕霉素的合适剂量。在本研究中，我们首先检测了mTOR信号通路的标志蛋白在发育过程中的变化。然后用不同剂量的雷帕霉素处理2周龄大鼠3d，检测其对mTOR通路的影响，确定雷帕霉素的剂量。然后用合适剂量的雷帕霉素处理幼鼠4周，并研究雷帕霉素对mTOR、发育和免疫的影响。我们发现mTOR通路的标志蛋白在脑发育过程中海马和新皮层的表达发生了变化。处理3天后，0.03 mg/kg雷帕霉素对磷酸化S6无影响，0.1、0.3、1.0和3.0 mg/kg雷帕霉素对磷酸化S6有剂量依赖性抑制作用。然而，只有1.0 mg/kg和3.0 mg/kg的雷帕霉素抑制磷酸S6后，4周的雷帕霉素治疗。与此结果平行，用0.1和0.3 mg/kg雷帕霉素处理的大鼠没有明显的副作用，而用1.0和3.0 mg/kg雷帕霉素处理的大鼠显示出身体、脾脏和胸腺重量的显著降低。此外，用1.0和3.0 mg/kg雷帕霉素处理的大鼠表现出认知障碍和焦虑，如迷宫和旷场实验所证实的。1.0和3.0mg/kg雷帕霉素组大鼠血清和大脑皮质中IL-1β、IL-2、IFN-γ、TNF-α含量均显著降低。在1.0和3.0 mg/kg雷帕霉素处理的大鼠中，DCX的表达也显著降低。然而，用1.0 mg/ kg雷帕霉素治疗的大鼠比用3.0 mg/kg雷帕霉素治疗的大鼠表现出更少和更轻的副作用。总之，所有这些数据表明，没有一种雷帕霉素剂量可以抑制癫痫的mTOR而不引起任何副作用，但1 mg /kg可能是年轻大鼠抑制mTOR的最佳剂量，副作用相对较少。
Mammalian target of rapamycin (mTOR) regulates cell growth, cell differentiation and protein synthesis. Rapamycin, an inhibitor of mTOR, has been widely used as an immunosuppressant and anti-cancer drug. Recently, mTOR inhibitors have also been reported to be a potential anti-epileptic drug, which may be effective when used in young patients with genetic epilepsy. Thus, a suitable dose of rapamycin which can maintain the normal function of mTOR and has fewer side effects ideally should be identified. In the present study, we first detected changes in marker proteins of mTOR signaling pathway during development. Then we determined the dose of rapamycin by treating rats of 2 weeks of age with different doses of rapamycin for 3 days and detected its effect on mTOR pathway. Young rats were then treated with a suitable dose of rapamycin for 4 weeks and the effect of rapamycin on mTOR, development and immunity were investigated. We found that the expression of the marker proteins of mTOR pathway was changed during development in brain hippocampus and neocortex. After 3 days of treanent, 0.03 mg/kg rapamycin had no effect on phospho-S6, whereas 0.1, 0.3, 1.0 and 3.0 mg/kg rapamycin inhibited phospho-S6 in a dose-dependent manner. However, only 1.0 mg/kg and 3.0 mg/kg rapamycin inhibited phospho-S6 after 4 weeks treatment of rapamycin. Parallel to this result, rats treated with 0.1 and 0.3 mg/kg rapamycin had no obvious adverse effects, whereas rats treated with 1.0 and 3.0 mg/kg rapamycin showed significant decreases in body, spleen and thymus weight. Additionally, rats treated with 1.0 and 3.0 mg/kg rapamycin exhibited cognitive impairment and anxiety as evident by maze and open field experiments. Furthermore, the content of IL-1β, IL-2, IFN-γ, TNF-α in serum and cerebral cortex were significantly decreased in 1.0 and 3.0 mg/kg rapamycin-treated rats. The expression of DCX was also significantly decreased in 1.0 and 3.0 mg/kg rapamycin-treated rats. However, rats treated with 1.0 mg/ kg rapamycin exhibited fewer and milder side effects than those treated with 3.0 mg/kg. In summary, all these data suggest that there is not a rapamycin dose that can inhibit mTOR for epilepsy without causing any side effects, but 1 mg /kg may be the optimal dose for young rats for suppressing mTOR with relatively few side effects.