| Summary: | 碩士 === 國立臺灣大學 === 分子與細胞生物學研究所 === 107 === Parkinson’s disease (PD) is the second most common neurodegenerative disease, clinically characterized by bradykinesia, resting tremor, and rigidity. The etiology of PD is attributed to the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNc), further decreasing the release of dopamine (DA) through the nigrostriatal pathway in the striatum, where dopamine binds to different subtypes of dopamine receptors, producing various responses (activation/inhibition) for the fine control of locomotor activity. Loss of these dopamine neurons in substantia nigra pars compacta results in insufficient levels of dopamine, thus breaking the balance of neurotransmission in the striatum. Specifically, the hallmark in both familial and sporadic PD is the presence of intra-neuronal proteinaceous inclusions, termed “Lewy Bodies”, mainly composed by phosphorylated alpha-Synuclein (α-Syn), which can be distributed across the whole brain during PD progression. However, how α-Syn aggregates propagate across brain or other systems remains unclear. In this study, we aim to establish a rat model to mimic PD during adulthood. With the technique of in vivo electroporation, we successfully transfected the pathological forms of human α-Syn (hα-Syn and hα-Syn-A53T) in the rat SNc. The results from immunostaining and immunoblotting showed that ectopic α-Syn and phosphorylated α-Syn (α-Syn-pS129) appeared in both sites of SNc, CPu, and other brain regions that were far away from the injected site, suggesting the ability of pathological α-Syn to propagate and aggregate within the CNS. In order to assess locomotor activities upon PD progression, we conducted the gait pattern analysis and found that foot angle was increased at 4-6 months post transfection of one-side SNc with hα-Syn or hα-Syn-A53T, indicating that the impaired ability in maintaining balance caused by these pathogenic α-Syn forms. Moreover, the numbers of DA neurons within SNc remained unchanged by transfection of these pathological α-Syn forms, implying that this model reflects an early stage of PD progression. Overall, this in vivo electroporation technique can be used as a gene delivery method to introduce the human pathogenic α-Syn in adult rats, serving as a suitable model in searching therapeutic methods for delaying the early-stage PDs.
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