腺苷A2A受体拮抗剂对左旋多巴诱发异动症大鼠行为、纹状体A2A受体和代谢型谷氨酸受体5亚型蛋白表达的影响

The effects of adenosine A2A receptor antagonist on the behavior and the striatal A2A receptor,metabotropic glutamate receptors protein expression in rats with levodopa-induced dyskinesia

目的 评价腺苷A2A受体拮抗剂（CSC）对左旋多巴（L-DOPA）诱发异动症大鼠行为、纹状体A2A受体和代谢型谷氨酸受体5亚型（mGluR5）蛋白表达的影响.方法 6-羟多巴胺（6-OHDA）立体定向损毁大鼠右内侧前脑束,建立单侧损毁帕金森病（PD）大鼠模型.采用随机数字表法将40只成功PD大鼠随机分为4组（每组10只）：生理盐水组;L-DOPA 25 mg/kg＋苄丝肼6.25 mg/kg组;CSC 2.5 mg/kg组;L-DOPA 25 mg/kg＋苄丝肼6.25 mg/kg联合CSC 2.5 mg/kg组.给予大鼠每日2次腹腔注射,持续21 d.在治疗第2、9、11、18、21天观察大鼠行为学变化,Western blot检测纹状体区腺苷A2A受体和mGluR5的蛋白表达水平.结果 L-DOPA联合CSC组PD大鼠损毁对侧前肢跨步数显著增加,与治疗前比较差异有统计学意义,与L-DOPA组相比,前肢功能改善程度不随时间延长而减弱.单独CSC组治疗后对侧前肢跨步数明显增加,与治疗前比较差异有统计学意义,有疗效逐渐增加至稳定趋势.L-DOPA联合CSC组[（11±5）分]部分口颌及肢体异常不自主运动评分较L-DOPA组[（17±4）分]显著减少,差异有统计学意义（t=2.44,P＜0.05）.L-DOPA联合CSC治疗逆转了L-DOPA诱导的对侧旋转反应时间缩短和腺苷A2A受体、mGluR5蛋白表达的上调,差异均有统计学意义.结论 腺苷A2A受体与mGluR5均参与了L-DOPA诱发的异动症的发生发展,A2A受体拮抗剂能够改善PD运动症状,增强L-DOPA的抗PD效应且部分减轻异常不自主运动,对L-DOPA诱发的异动症的治疗有着较好的应用前景.

Objective To study the behavioural changes and biological effects of selective adenosine A2A receptor antagonist （CSC） in a rat model of levodopa（L-DOPA） -induced dyskinesia （LID）.Methods The hemi-parkinsonian rat model was produced by stereotaxically injecting 6-OHDA to the right medial forebrain bundle. Rats were randomly divided into 4 treatment groups with a random number generating program to receive intraperitoneal injections twice daily for 21 days （n = 10）： saline, L-DOPA at 25 mg/kg with benserazide at 6. 25 mg/kg, CSC at 2. 5 mg/kg alone and CSC at 2.5 mg/kg with L-DOPA at 25 mg/kg plus benserazide at 6. 25 mg/kg. Forepaw adjusting steps, abnormal involuntary movements （AIM） and rotational response duration were observed on 2, 9, 11,18 and 21 d. After sacrifice, the expression of adenosine A2A R and mGluR5 was observed by Western blot. Results Co-administration of LDOPA with CSC significantly increased the forelimb adjusting steps of parkinsonian rats during 21 days of treatment when compared to L-DOPA alone. CSC treatment alone increased the forelimb adjusting steps significantly. Co-administration of L-DOPA with CSC （ （ 11 ± 5 ） score） significantly decreased the AIM scores of limb and orolingual muscles when compared to L-DOPA alone （（ 17 ± 4） score; t = 2. 44, P 〈0. 05）. The subchronic L-DOPA treatment upregulated the striatal expression of adenosine A2A R and mGluR5. However, co-administration of L-DOPA with CSC reversed the shortening of the rotational motor response duration induced by L-DOPA administration during the period of the treatment and attenuated the LDOPA-induced upregulation of adenosine A2A R and mGluR5 expressions. Conclusions CSC improves motor function in a hemi-parkinson rat model, potentiates the antiparkinsonian effects with L-DOPA and partly attenuates LID. Co-administration of L-DOPA with CSC reverses the L-DOPA-induced upregulated expression of A2A R and mGluR5, indicating the involvement of both A2A R and mGluR5 in the onset and progression of LID. Adenosine A2AR antagonists may be promising drugs for treatment of LID.