Author(s): MORALES-ÁLAMO, D.1,2,3, TORRES-REYES, S.3, MARTÍN RODRÍGUEZ, S.1,2,3, Institution: LAS PALMAS UNIVERSITY, Country: SPAIN, Abstract-ID: 656

INTRODUCTION:
Parkinson’s disease (PD) is characterized by the aggregation of toxic cytoplasmic inclusions called Lewy bodies (LBs) and Lewy neurites (LNs), leading to dopaminergic loss in the substantia nigra. The primary component of LBs and LNs is the protein alpha-synuclein (alpha-Syn). Exercise has been shown to be effective as a complementary therapy for PD, resulting in the alleviation of some motor symptoms and improvements in quality of life. However, despite numerous physiological mechanisms proposed to explain the neuroprotective effect of physical exercise, only a growing body of animal research aims to determine if physical exercise can modulate alpha-Syn expression under PD conditions. This systematic review investigates whether endurance exercise reduces alpha-Syn levels in the substantia nigra in animal models of PD.
METHODS:
PRISMA Guidelines were strictly followed. We systematically searched relevant articles in Web of Science, Medline/PubMed, Scopus, and Cochrane Library from inception to January 2024. The total sample size across the 8 included studies was 356 mice (i.e., only 116 received exercise intervention). To evaluate the risk of bias, the SYRCLE’s RoB tool for animal studies was used.
RESULTS:
343 articles were identified from the databases (55 in PubMed; 6 in Cochrane Library; 115 in Web of Science and 167 in Scopus). Out of 247 articles (without duplicates) that were screened, 27 studies met the inclusion criteria for the first and 10 studies for the second screening review. All studies showed a decrease in alpha synuclein levels following aerobic exercise intervention. The exercise led to significant reductions in alpha-Syn in all models treated with intraperitoneal injection of MPTP. The mouse models of Parkinsons disease induced by triacetyl-6-OHDA injection also experienced a reduction in alpha-Syn expression with resistance exercise intervention.
CONCLUSION:
Animal experiments consistently showed a clear downregulation in alpha-Syn expression in response to aerobic exercise compared to sedentary control groups. Nevertheless, caution is warranted in interpreting these findings due to inherent limitations and inconsistencies in standardization and reporting quality within the domain of animal research.