An overview of the molecular and physiological antidepressant mechanisms of physical exercise in animal models of depression

Physical Exercise Inhibits Cognitive Impairment and Memory Loss in Aged Mice, and Enhances Pre- and Post-Synaptic Proteins in the Hippocampus of Young and Aged Mice

The aim of this study was to evaluate the effects of swimming in the brain and behavior of young and aged mice. Forty-eight male C57BL/6 J mice were randomly distributed into 4 groups (n = 12 per group, 3 and 18 months old). The subdivision of the groups was: 3 months-SED, 18 months-SED, 3 months-EXE, and 18 months-EXE. SED mice did not swim, while EXE mice performed the physical exercise protocol. Training was initiated 48 h after the adaptation week. Swimming sessions consisted of 30 min, with no overload, 5 days per week, for 4 weeks. After the exercise protocol, it was revealed working and spatial memory were impaired in the 18 months-SED group. Pre- and post-synaptic proteins were enhanced in the groups that swam when compared to the 3- and 8 months-SED groups. Lipid peroxidation was greater in the aged mice that did not perform the physical exercise protocol and might have contributed to the cognitive impairment in this group. In conclusion, an aerobic physical exercise protocol, performed through regular swimming sessions, inhibited cognitive impairment, memory loss and lipid peroxidation in the aged mice, while pre- and post-synaptic proteins were enhanced in the hippocampus of young and aged mice.

Association between Depressive Symptoms, Physical Activity, and Health Factors in Hispanic Emerging Adults

Physical activity is a modifiable lifestyle behavior known for reducing symptoms of and being a risk factor for depression and mental health disorders. However, emerging adults (ages 18-25) struggle to meet recommended amounts. In this study, we explore the association between physical activity, depressive symptoms, and health factors in 137 Hispanic emerging adults. Using a cross-sectional survey design, sociodemographic information, depressive symptoms (CES-D score), physical activity (IPAQ score), body composition, and blood pressure measures were obtained. Statistical analyses included correlation and regression analyses. More than half of the participants demonstrated depressive symptomology (59.1%) and body fat percentage greater than 25% (64.2%). Body fat percentage, lean body mass, stress, and heart rate demonstrated notable associations with depressive symptoms and physical activity. When measured continuously and categorically, IPAQ was not a significant predictor of depressive symptoms. When used as a binary variable with a cutoff of 600 MET min/week, IPAQ score revealed a negative relationship with CES-D score (β = -0.169, SE = 2.748, p = 0.034). Our results indicate that a threshold of physical activity, 600 MET min/week, may confer protective effects against depressive symptoms. Future research should investigate the context and quality of physical activity to address mental health disparities in this underrepresented population.

Relationship between physical activity and risk of depression in a married group

BACKGROUND

Currently, there are many different findings on the relationship between physical activity and depression, and there may be differences between genders. This study therefore focused on gender differences to understand the relationship between physical activity behaviour and the risk of depression in married individuals.

METHODS

15607 married people in the China Family Panel Studies 2020 (CFPS 2020) were used to understand the relationship between physical activity and depression risk in different populations, and the chi-square test, Mann-Whitney U-test, and binary logistic regression were used to explore the relationship between physical activity and depression risk in the married population.

RESULTS

527 (6.64%) women were at high risk of depression and 365 (4.76%) men were at high risk of depression; physical activity was associated with the risk of depression in the married population, but after incorporating demographic and relevant cognitive variables, physical activity was negatively associated with the risk of depression in women (OR = 0.94, P < 0.01) but not statistically significant with the risk of depression in men (OR = 0.96, P > 0.05).

CONCLUSION

Physical activity was directly related to the risk of depression in married women, but not in married men.

Effect of acute and long-term exercise on leptin levels in depressed outpatients

BACKGROUND

Depression is a leading cause of disability worldwide and a significant contributor to the global burden of disease. Altered leptin levels are known to be associated with depressive symptoms, however discrepancies in the results of increased or decreased levels exist. Due to various limitations associated with commonly used antidepressant drugs, alternatives such as exercise therapy are gaining more importance. Therefore, the current study investigates whether depressed patients have higher leptin levels compared to healthy controls and if exercise is efficient to reduce these levels.

METHODS

Leptin levels of 105 participants with major depressive disorder (MDD; 45.7% female, age mean ± SEM: 39.1 ± 1.0) and 34 healthy controls (HC; 61.8% female, age mean ± SEM: 36.0 ± 2.0) were measured before and after a bicycle ergometer test. Additionally, the MDD group was separated into three groups: two endurance exercise intervention groups (EX) differing in their intensities, and a waiting list control group (WL). Leptin levels were measured pre and post a 12-week exercise intervention or the waiting period.

RESULTS

Baseline data showed no significant differences in leptin levels between the MDD and HC groups. As expected, correlation analyses displayed significant relations between leptin levels and body weight (HC: r = 0.474, p = 0.005; MDD: r = 0.198, p = 0.043) and even more with body fat content (HC: r = 0.755, p < 0.001; MDD: r = 0.675, p < 0.001). The acute effect of the bicycle ergometer test and the 12-week training intervention showed no significant changes in circulating leptin levels.

CONCLUSION

Leptin levels were not altered in patients with major depression compared to healthy controls and exercise, both the acute response and after 12 weeks of endurance training, had no effect on the change in leptin levels.

TRIAL REGISTRATION

The study was registered at the German register for clinical studies (DRKS) and the International Clinical Trials Registry Platform of the World Health Organization https://trialsearch.who.int/Trial2.aspx?TrialID=DRKS00008869 on 28/07/2015.

Running from depression: the antidepressant-like potential of prenatal and pre-pubertal exercise in adolescent FSL rats exposed to an early-life stressor

OBJECTIVE

We aimed to answer the questions of whether early-life (perinatal and/or juvenile) exercise can induce antidepressant-like effects in a validated rodent model of depression, and whether such early-life intervention could prevent or reverse the adverse effects of early-life stress in their offspring.

METHODS

Male and female Flinders sensitive line rats born to a dam that exercised during gestation, or not, were either maternally separated between PND02 and 16 and weaned on PND17 or not. Half of these animals then underwent a fourteen-day low-intensity exercise regimen from PND22. Baseline depressive-like behaviour was assessed on PND21 and then reassessed on PND36, whereafter hippocampal monoamine levels, redox state markers and metabolic markers relevant to mitochondrial function were measured.

RESULTS

Pre-pubertal exercise was identified as the largest contributing factor to the observed effects, where it decreased immobility time in the FST by 6%, increased time spent in the open arms of the EPM by 9%. Hippocampal serotonin and norepinephrine levels were also increased by 35% and 26%, respectively, whilst nicotinic acid was significantly decreased.

CONCLUSION

These findings suggest that pre-pubertal low-intensity exercise induces beneficial biological alterations that could translate into antidepressant behaviour in genetically susceptible individuals.

Long-term consequences of COVID-19 on mental health and the impact of a physically active lifestyle: a narrative review

BACKGROUND

Coronavirus-19 disease (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Respiratory viruses damage not only the upper respiratory tract in humans, but also several different organs such as the brain. Some of the neurological consequences of COVID-19 reported are anosmia, headache, stroke, declined cognitive function, and impaired mental health, among others. People who had COVID-19 have a higher risk of sequelae in the central nervous system (CNS). However, it is not known which are all possible sequelae and how long will last the long-term effects of the COVID-19 pandemic on behavioral patterns and quality of life.

AIM

We intend to address the long-term impacts of COVID-19 on mental health and the relevance of physical exercise during the pandemic.

METHODS

We conducted a literature search using PubMed to find the articles that were related to these themes.

RESULTS

We found 23,489 papers initially, and then we applied the inclusion/exclusion criteria to narrow down our search to 3617 articles and selected 1380 eligible articles after a thorough reading of titles and abstracts. The findings indicated that COVID-19 impacted general mental health and led many not only hospitalized patients to develop cognitive decline, memory impairment, anxiety, sleep alterations, and depressive-like behavior. Furthermore, the fear of vaccines and their effects had negatively affected mental health and directly impacted mortality rates in unvaccinated COVID-19 patients.

CONCLUSIONS

Preventive measures must be undertaken, such as the vaccination of the entire population, vaccination hesitancy discouragement by creating awareness among individuals, and people's engagement in a physically active lifestyle, since being physically active is a low-cost and effective measure to restore or inhibit the negative outcomes from COVID-19 on mental health.

Integrating Metabolomics and Network Analysis for Exploring the Mechanism Underlying the Antidepressant Activity of Paeoniflorin in Rats With CUMS-Induced Depression

Background: Paeoniflorin (PF) represents the major bioactive constituent of the traditional Chinese medicine plant Paeonia suffruticosa (Ranunculaceae), which has a long history as a folk medicine in Asian. Paeoniflorin, a bitter pinene monoterpene glycoside, has antidepressant effects, but its potential therapeutic mechanism has not been thoroughly explored.

Methods: Experimental depression in rats was established by the chronic unpredictable mild stress (CUMS) combined with orphan method, and the efficacy of paeoniflorin on depression was evaluated by the sucrose preference test and open field test. The antidepressant mechanism of paeoniflorin was investigated by metabolomic and network pharmacology. The relevant pathways of biomarkers highlighted in metabolomics were explored, and the possible targets of paeoniflorin in the treatment of depression were further revealed through network analysis. The binding activity of paeoniflorin to key targets was verified by molecular docking.

Results: Metabolomics showed that rats with CUMS-induced depression had urine metabolic disorders, which were reversed by paeoniflorin through the regulation of metabolic pathways. Metabolites that play a key role in the function of paeoniflorin include citric acid, thiamine monophosphate, gluconolactone, 5-hydroxyindoleacetic acid and stachyose. Key predicted targets are SLC6A4, TNF, IL6 and SLC6A3. An important metabolic pathway is the Citrate cycle (TCA cycle).

Conclusion: Network integrative analysis in this study showed that paeoniflorin could improve depressive-like symptoms in model rats with CUMS-induced depression and overall correct the disordered metabolic profile through multiple metabolic pathways.

The association between physical activity and mental health in medical postgraduates in China during COVID-19 pandemic

BACKGROUND

Chinese medical postgraduates (CMPs) are a special subpopulation that has a great risk of mental health due to high workload, and heavy academic and clinical pressure during the COVID-19 pandemic. Physical activity has been demonstrated to be positive for the mental health of human being. However, little is known about the risks to mental health among CMPs as well as the potential effects of physical activity on mental health in CMPs during the COVID-19 pandemic.

AIMS

In the present study, the aims are to (1) investigate the levels of PA and mental health that CMPs had; (2) to identify the potential factors that contribute to mental health among CMPs; (3) to explore the potential effects of PA on the mental health in CMPs.

METHODS

The survey was conducted online across 25 provinces of mainland China in 28 medical colleges or universities with structured questionnaires. Physical Activity Rating Scale-3 (PARS-3), Depression, Anxiety, Stress Scales (DASS-21), and General Self-Efficacy Scale (GSES) were employed to assess the levels of PA, Negative emotional states, and self-efficacy of the participants, respectively. Resilience was evaluated using Connor-Davidson Resilience Scale (CD-RISC). The chi-square and Wilcoxon rank-sum tests were used to compare inter-group differences in demographic data and mental health conditions. Spearman's rank correlation test and partial correlation analysis were used to assess associations between exercise scores and mental health.

RESULTS

We found some socio-demographic variables such as the location, education levels of parents and the levels of degrees they are training had potential effects on outcomes of mental health among 2,217 CMPs (P < 0.05); furthermore, we also found that PA was negatively correlated with the negative emotion (r = -0.045, P < 0.05) such as depression (r = -0.052, P < 0.05), anxiety and stress, (r = -0.051, P < 0.05) but positively correlated with the self-efficacy (r = 0.143, P < 0.001) and resilience (r = 0.192, P < 0.001) among Chinese postgraduate medical students.

CONCLUSION

We concluded that for Chinese postgraduate medical students, taking part in physical activity would depress negative emotions such as depression, anxiety, and stress, but improve their self-efficacy and resilience, which will benefit them in completing their studies and training.