Exercício resistido na função cognitiva e ansiedade de modelos animais com doença de Alzheimer

Abstract

Introduction: Cognitive function impairment is one of the main characteristics of Alzheimer's disease (AD). Cognitive abilities are important predictors of health and functionality, and their decline can compromise quality of life. Exercise has been extensively studied as a preventive factor for cognitive decline, and resistance exercise (RE) has been proposed as an alternative for preventing AD. Objective: to conduct a systematic review and meta-analysis to investigate the effects of resistance exercise (RE) on cognitive function in animal models of Alzheimer's disease (AD) and its physiological mechanisms. Method: This review followed the PRISMA checklist and had its protocol registered in PROSPERO (CRD42019131266). Four databases were searched: MedLine/PubMed, Scopus, Web of Science, and Google Scholar, without filters for year of publication or language. Eligibility criteria followed the PICOS strategy (P: animals—rats and mice with AD; I: resistance exercise; C: sedentary or sham; O: cognitive function (memory) and anxiety; S: preclinical experimental studies). Risk of bias and methodological quality were assessed using two tools: SYRCLE and CAMARADES. For the meta-analysis, the standardized mean difference was calculated using 95% confidence intervals, considering a random-effects model and p < 0.05 for significance, while Higgins' index was used to observe heterogeneity. Results: A total of 1,807 studies were identified. After completing the screening and selection process, 11 studies were included in this review, and nine were included in the meta-analysis. Four studies applied RE before AD induction, while seven applied RE after AD induction or in the AD condition. All studies included 550 adult and older animals weighing between 25–280g. Only two studies included female animals. In the meta-analysis, a significant effect of RE on memory was observed (p = 0.001) with a large effect size (ES) (1.02; 95% CI: 0.41–1.64) and moderate heterogeneity (I² = 66%) compared to the control group, but no significant effect was found for anxiety (p = 0.22). The included studies presented a high risk of bias and moderate methodological quality. Conclusion: This review suggests that RE, when performed for four to six weeks, more than three days per week, had an effect on memory decline, despite the heterogeneity of the included studies. However, there is no evidence of its impact on anxiety. Therefore, RE may be a potential strategy to prevent cognitive decline caused by AD in animal models.