Department of Neurology, Xinhua Hospital (affiliated to Shanghai Jiaotong University School of Medicine), Shanghai, People's Republic of China.
Int J Nanomedicine. 2012;7:2077-86. doi: 10.2147/IJN.S30463. Epub 2012 Apr 19.
Levodopa remains the most effective drug in the treatment of Parkinson's disease. However, long-term administration of levodopa induces motor complications, such as levodopa-induced dyskinesia. The mechanisms underlying levodopa-induced dyskinesia are not fully understood.
In this study, we prepared levodopa methyl ester (LDME)/benserazide-loaded nanoparticles, which can release LDME and benserazide in a sustained manner. Dyskinesia was induced in rats by repeated administration of levodopa then treated with LDME plus benserazide or the same dose of LDME/benserazide-loaded nanoparticles. Apomorphine- induced rotations and abnormal involuntary movements (AIMs) were measured on treatment days 1, 5, 10, 15, and 20. In addition, the levels of phosphorylated dopamine- and cyclic adenosine monophosphate- regulated phosphoprotein of 32 kDa, extracellular signal-regulated kinases 1/2, and ΔfosB were determined by Western blot. Tau levels were determined by Western blot and immunohistochemistry. Dynorphin levels in the striatum and cortex of rats were measured using enzyme-linked immunosorbent assay.
Over the course of levodopa treatment, the rats developed abnormal AIMs, classified as locomotive, axial, orolingual, and forelimb dyskinesia. The degree of reduction of apomorphine-induced rotations was comparable in dyskinetic rats treated with LDME plus benserazide or LDME/benserazide-loaded nanoparticles. The axial, limb, and orolingual (ALO) AIMs of dyskinetic rats treated with LDME/benserazide-loaded nanoparticles were 14 ± 2.5, 9 ± 2.0, and 10 ± 2.1 on treatment days 10, 15, and 20, respectively, which were significantly reduced compared with dyskinetic rats treated with LDME plus benserazide (25 ± 3.7, 27 ± 3.8, and 25 ± 3.5, respectively). The locomotive AIMs of dyskinetic rats treated with LDME/benserazide-loaded nanoparticles were 2.3 ± 0.42, 1.7 ± 0.35, and 1.6 ± 0.37 on treatment days 10, 15, and 20, respectively, which were also reduced compared with dyskinetic rats treated with LDME plus benserazide (4.4 ± 0.85, 4.7 ± 0.95 and 4.8 ± 0.37, respectively). Western blot showed that the levels of phosphorylated dopamine- and cyclic adenosine monophosphate-regulated phosphoprotein of 32 kDa, extracellular signal-regulated kinases 1/2, tau, and ΔfosB in dyskinetic rats treated with LDME/benserazide-loaded nanoparticles were 134.6 ± 14.1, 174.9 ± 15.1, 134.2 ± 19.3, and 320.5 ± 32.8, respectively, which were significantly reduced compared with those of dyskinetic rats treated with LDME plus benserazide (210.3 ± 19.7, 320.8 ± 21.9, 340.4 ± 27.1, and 620.7 ± 48.3, respectively). Immunohistochemistry indicated that the level of phosphorylated tau was (7.2 ± 1.1) × 10(4) in dyskinetic rats treated with LDME/benserazide-loaded nanoparticles. However, the tau level was only (14.6 ± 2.3) × 10(4) in LDME plus benserazide-treated dyskinetic rats. There was a significant difference between the two groups. Enzyme-linked immunosorbent assay showed that dynorphin levels in the striatum and cortex of dyskinetic rats treated with LDME/benserazide-loaded nanoparticles were 5.7 ± 1.2 and 4.8 ± 0.87, respectively, which were significantly reduced compared with LDME plus benserazide-treated dyskinetic rats (13.3 ± 2.1 and 8.1 ± 1.1 for the striatum and cortex, respectively).
Results suggest that LDME/benserazide-loaded nanoparticles can be used to reduce the expression of dyskinesia in dyskinetic rats.
左旋多巴仍然是治疗帕金森病最有效的药物。然而，长期使用左旋多巴会引起运动并发症，如左旋多巴诱导的运动障碍。左旋多巴诱导运动障碍的机制尚不完全清楚。
本研究制备了左旋多巴甲酯（LDME）/苯丝肼载药纳米粒，其可以持续释放 LDME 和苯丝肼。通过给予左旋多巴重复诱导运动障碍，然后用 LDME 加苯丝肼或相同剂量的 LDME/苯丝肼载药纳米粒进行治疗。在治疗第 1、5、10、15 和 20 天，测量阿扑吗啡诱导的旋转和异常不自主运动（AIMs）。通过 Western blot 测定磷酸化多巴胺和环磷酸腺苷调节的 32 kDa 磷酸化蛋白、细胞外信号调节激酶 1/2 和 ΔfosB 的水平。通过 Western blot 和免疫组织化学测定 Tau 水平。采用酶联免疫吸附试验测定大鼠纹状体和皮质中的强啡肽水平。
在左旋多巴治疗过程中，大鼠出现异常 AIMs，分为运动、轴性、口咽和前肢运动障碍。用 LDME 加苯丝肼或 LDME/苯丝肼载药纳米粒治疗的运动障碍大鼠，阿扑吗啡诱导的旋转减少程度相当。用 LDME/苯丝肼载药纳米粒治疗的运动障碍大鼠的轴性、肢体和口咽（ALO）AIMs 在治疗第 10、15 和 20 天分别为 14±2.5、9±2.0 和 10±2.1，与用 LDME 加苯丝肼治疗的运动障碍大鼠相比（分别为 25±3.7、27±3.8 和 25±3.5）显著减少。用 LDME/苯丝肼载药纳米粒治疗的运动障碍大鼠的运动 AIMs 在治疗第 10、15 和 20 天分别为 2.3±0.42、1.7±0.35 和 1.6±0.37，与用 LDME 加苯丝肼治疗的运动障碍大鼠相比（分别为 4.4±0.85、4.7±0.95 和 4.8±0.37）也减少。Western blot 显示，用 LDME/苯丝肼载药纳米粒治疗的运动障碍大鼠的磷酸化多巴胺和环磷酸腺苷调节的 32 kDa 磷酸化蛋白、细胞外信号调节激酶 1/2、Tau 和 ΔfosB 水平分别为 134.6±14.1、174.9±15.1、134.2±19.3 和 320.5±32.8，与用 LDME 加苯丝肼治疗的运动障碍大鼠相比（分别为 210.3±19.7、320.8±21.9、340.4±27.1 和 620.7±48.3）显著降低。免疫组织化学显示，用 LDME/苯丝肼载药纳米粒治疗的运动障碍大鼠磷酸化 Tau 水平为（7.2±1.1）×10（4）。然而，用 LDME 加苯丝肼治疗的运动障碍大鼠的 Tau 水平仅为（14.6±2.3）×10（4）。两组之间有显著差异。酶联免疫吸附试验显示，用 LDME/苯丝肼载药纳米粒治疗的运动障碍大鼠纹状体和皮质中的强啡肽水平分别为 5.7±1.2 和 4.8±0.87，与用 LDME 加苯丝肼治疗的运动障碍大鼠相比（分别为 13.3±2.1 和 8.1±1.1）显著降低。
结果表明，LDME/苯丝肼载药纳米粒可用于减少运动障碍大鼠的运动障碍表达。
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