背景:运动疗法作为一种重要的实用、无副作用的辅助疗法,在临床康复中得到了广泛的应用。在缓解帕金森病(PD)患者或动物PD模型的运动功能障碍方面具有显着效果。本研究通过上调Ⅱ组代谢型Glu受体(mGluR2/3)的表达,探讨运动疗法在降低大鼠PD模型纹状体细胞外谷氨酸(Glu)浓度中的作用,从而减轻PD模型大鼠的运动功能障碍。方法:将神经毒素6-羟基多巴胺(6-OHDA)注射到大鼠右内侧前脑束(MFB)中,建立半外侧脑损伤PD模型。假手术组在相同部位给予等量生理盐水作为对照组。进行了阿扑吗啡(APO)诱导的旋转行为测试,并结合黑质(SNc)和纹状体中酪氨酸羟化酶(TH)的免疫组织化学染色,以评估模型的可靠性。运动组给予跑步机运动干预4周(11m/min,30分钟/天,5天/周)术后1周。采用开场试验(OFT)评估大鼠的运动活性;采用Westernblot技术检测SNcTH和纹状体mGluR2/3蛋白表达;采用实时聚合酶链反应(RT-PCR)检测纹状体mGluR2和mGluR3mRNA表达;采用微透析-高效液相色谱(HPLC)方法检测纹状体神经元细胞外Glu浓度。结果:与对照组相比,各模型组在第1周的旋转次数显著增加(P<0.01);与PD组相比,PD+运动组第三周和第五周的旋转次数明显减少(P<0.05,P<0.01)。与对照组相比,总移动距离,总运动时间,各模型组第1周平均速度均显著降低(P<0.05);与PD组相比,总移动距离,总运动时间,PD运动组第三周和第五周的平均速度显着增加(P<0.01)。与对照组相比,免疫阳性细胞计数和SNcTH蛋白表达,各模型组纹状体TH中免疫阳性纤维末端的含量显着下降(P<0.01)。与PD组相比,PD+运动组纹状体mGluR2/3蛋白表达显著升高(P<0.01)。与对照组相比,各模型组纹状体神经元细胞外Glu浓度在第1周显著升高(P<0.05);与PD组相比,PD+运动组纹状体神经元细胞外Glu浓度在第3周和第5周显著降低(P<0.01);与PD+运动组相比,注射mGluR2/3拮抗剂(RS)-1-氨基-5-膦酰基茚满-1-羧酸(APICA)组纹状体神经元细胞外Glu的浓度在第三周和第五周显着增加(P<0.05,P<0.01)。与对照组相比,PD组纹状体mGluR2/3蛋白表达明显下调(P<0.01);与PD组相比,PD+运动组纹状体mGluR2/3蛋白表达明显上调(P<0.05);与对照组相比,PD组纹状体mGluR3mRNA表达显著下调(P<0.01);与PD组相比,PD+运动组纹状体mGluR3mRNA表达显著上调(P<0.01);6-OHDA损伤和运动干预对纹状体mGluR2mRNA表达无显著影响(P>0.05)。与PD+运动组相比,总移动距离,总运动时间,PD+运动+APICA组平均速度明显下降(P<0.05);与PD组相比,PD+运动+APICA组总运动距离无明显变化,总运动时间,和平均速度(P>0.05)。结论:这些数据共同表明,纹状体中mGluR2/3介导的谷氨酸能传递对多巴胺(DA)消耗敏感,并且可以作为运动干预的目标,以介导运动干预在大鼠模型中的治疗作用PD。
Background: Exercise therapy has been widely applied in clinical rehabilitation as an important practical and side effect-free adjuvant therapy, with a significant effect in alleviating motor dysfunction of patients with Parkinson\'s disease (PD) or animal PD models. This study focuses on the effect of exercise therapy in reducing the concentration of extracellular glutamate (Glu) in the striatum in a rat PD model by upregulating the expression of group II metabotropic Glu receptor (mGluR2/3), so as to alleviate motor dysfunction in the rat PD model. Methods: Neurotoxin 6-hydroxydopamine (6-OHDA) was injected into the right medial forebrain bundle (MFB) of the rats to establish the semi-lateral cerebral damage PD model. The sham-operated group was given an equal amount of normal saline at the same site and taken as the control group. The apomorphine (APO)-induced rotational behavior test combined with immunohistochemical staining with tyrosine hydroxylase (TH) in the substantia nigra (SNc) and striatum was performed to assess the reliability of the model. The exercise group was given treadmill exercise intervention for 4 weeks (11 m/min, 30 min/day, 5 days/week) 1 week after the operation. The open field test (OFT) was performed to assess the locomotor activity of the rats; the Western blot technique was used to detect SNc TH and striatal mGluR2/3 protein expressions; real-time polymerase chain reaction (RT-PCR) was applied to detect striatal mGluR2 and mGluR3 mRNA expressions; the microdialysis-high-performance liquid chromatography (HPLC) method was adopted to detect the concentration of extracellular Glu in striatal neurons. Results: Compared with the control group, the number of rotations of each model group at the first week was significantly increased (P < 0.01); compared with the PD group, the number of rotations of the PD + exercise group at the third week and the fifth week was significantly decreased (P < 0.05, P < 0.01). Compared with the control group, the total movement distance, the total movement time, and the mean velocity of each model group at the first week were significantly reduced (P < 0.05); compared with the PD group, the total movement distance, the total movement time, and the mean velocity of the PD + exercise group at the third week and the fifth week were significantly increased (P < 0.01). Compared with the control group, the count of immunopositive cells and protein expression of SNc TH, and the content of immunopositive fiber terminals in the striatal TH of each model group significantly declined (P < 0.01). Compared with the PD group, the striatal mGluR2/3 protein expression of the PD + exercise group significantly rose (P < 0.01). Compared with the control group, the concentration of extracellular Glu in striatal neurons of each model group at the first week significantly grew (P < 0.05); compared with the PD group, the concentration of extracellular Glu in striatal neurons of the PD + exercise group at the third week and the fifth week was significantly decreased (P < 0.01); compared with the PD + exercise group, the concentration of extracellular Glu in striatal neurons of the group injected with mGluR2/3 antagonist (RS)-1-amino-5-phosphonoindan-1-carboxylic acid (APICA) into the striatum at the third week and the fifth week was significantly increased (P < 0.05, P < 0.01). Compared with the control group, the striatal mGluR2/3 protein expression of the PD group was significantly downregulated (P < 0.01); compared with the PD group, the striatal mGluR2/3 protein expression of the PD + exercise group was significantly upregulated (P < 0.05); compared with the control group, the striatal mGluR3 mRNA expression of the PD group was significantly downregulated (P < 0.01); compared with the PD group, the striatal mGluR3 mRNA expression of the PD + exercise group was significantly upregulated (P < 0.01); 6-OHDA damage and exercise intervention had no significant effect on the striatal mGluR2 mRNA expression (P > 0.05). Compared with the PD + exercise group, the total movement distance, the total movement time, and the mean velocity of the PD + exercise + APICA group were significantly decreased (P < 0.05); compared with the PD group, the PD + exercise + APICA group had no significant change in the total movement distance, the total movement time, and the mean velocity (P > 0.05). Conclusion: These data collectively demonstrate that the mGluR2/3-mediated glutamatergic transmission in the striatum is sensitive to dopamine (DA) depletion and may serve as a target of exercise intervention for mediating the therapeutic effect of exercise intervention in a rat model of PD.