The relationship between the dyskinesia in Parkinson disease and the degree of substantia nigra lesion / 中华老年医学杂志

ABSTRACT

Objective To explore the relationship between the genesis of dyskinesia and the degree of substantia nigra lesion in Parkinson disease(PD).Methods The hemi-parkinsonian rat model was established by injecting 6-OHDA stereotaxically to right medial forebrain bundle(MFB). Then the hemi-parkinsonian rat was injected intraperitoneally with levodopa methylester(25 mg?kg~(-1)?d~(-1),twice a day)for 21 days,the abnormal involuntary movements were estimated.After being sacrificed,the midbrain was removed,and the injured degree of dopaminergic neurons at substantia nigra was observed by tyrosine hydroxylase immunohistochemistry staining.The relationship between the abnormal involuntary movement scores and dopaminergic neurons loss at substantia nigra was evaluated by sigmoid equation analysis by using Excel software.Results The apomorphine-induced rotation rate above 7 r/min was found in 10 of 25 rats,those rats were regarded as successful hemi-parkinsonian model rats.After the treatment with levodopa methylester,8 of 10 rats displayed abnormal involuntary movements,including stereotype and contralateral rotation,the types of movements varied.Abnormal involuntary movements were appeared in the rats with dopaminergic neurons loss above 90%.The positive relationship was observed between the degree of lesion in substantia nigra and the severity of abnormal involuntary movements.Conclusions The severe loss of dopaminergic neurons at substantia nigra probably plays a role in the development of levodopa-induced dyskinesia in patient with Parkinson disease.