Institute of Clinical Pharmacology, Medical Faculty, Goethe-University, 60590 Frankfurt, Germany.
Int J Mol Sci. 2021 Aug 31;22(17):9496. doi: 10.3390/ijms22179496.
Rodent models of Parkinson's disease are based on transgenic expression of mutant synuclein, deletion of PD genes, injections of MPTP or rotenone, or seeding of synuclein fibrils. The models show histopathologic features of PD such as Lewi bodies but mostly only subtle in vivo manifestations or systemic toxicity. The models only partly mimic a predominant loss of dopaminergic neurons in the substantia nigra. We therefore generated mice that express the transgenic diphtheria toxin receptor (DTR) specifically in DA neurons by crossing DAT-Cre mice with Rosa26 loxP-STOP-loxP DTR mice. After defining a well-tolerated DTx dose, DAT-DTR and DTR-flfl controls were subjected to non-toxic DTx treatment (5 × 100 pg/g) and subsequent histology and behavioral tests. DAT protein levels were reduced in the midbrain, and tyrosine hydroxylase-positive neurons were reduced in the substantia nigra, whereas the pan-neuronal marker NeuN was not affected. Despite the promising histologic results, there was no difference in motor function tests or open field behavior. These are tests in which double mutant Pink1SNCA Parkinson mice show behavioral abnormalities. Higher doses of DTx were toxic in both groups. The data suggest that DTx treatment in mice with Cre/loxP-driven DAT-DTR expression leads to partial ablation of DA-neurons but without PD-reminiscent behavioral correlates.
帕金森病的啮齿动物模型基于突变型突触核蛋白的转基因表达、PD 基因缺失、MPTP 或鱼藤酮注射,或突触核蛋白原纤维的播种。这些模型显示出帕金森病的组织病理学特征,如路易体,但大多只有细微的体内表现或全身毒性。这些模型仅部分模拟了黑质中多巴胺能神经元的主要丧失。因此,我们通过将 DAT-Cre 小鼠与 Rosa26 loxP-STOP-loxP DTR 小鼠杂交,生成了在 DA 神经元中特异性表达转基因白喉毒素受体 (DTR) 的小鼠。在确定了耐受良好的 DTx 剂量后,DAT-DTR 和 DTR-flfl 对照接受了非毒性 DTx 治疗(5×100pg/g),然后进行组织学和行为测试。中脑的 DAT 蛋白水平降低,黑质中的酪氨酸羟化酶阳性神经元减少,而泛神经元标志物 NeuN 不受影响。尽管组织学结果很有希望,但在运动功能测试或旷场行为中没有差异。这些是双突变 Pink1SNCA 帕金森小鼠表现出行为异常的测试。两组的更高剂量 DTx 都是有毒的。数据表明,在具有 Cre/loxP 驱动的 DAT-DTR 表达的小鼠中,DTx 治疗会导致 DA 神经元的部分消融,但没有 PD 样行为相关性。