Voluntary versus forced exercise modulates anxiety‑like behaviors and hippocampal inflammation gene expression following traumatic stress in rats.
Both voluntary and forced exercise can reduce anxiety-like behaviors and inflammation in a rat model of PTSD, with voluntary exercise showing greater behavioral benefits.
Where it sits
this study against the rest of the slu-pp-332 (exercise mimetic) corpusSummary and findings
This study examined the effects of voluntary versus forced exercise on anxiety-like behaviors and hippocampal inflammation in rats following traumatic stress. Adult male rats were subjected to a single prolonged stress (SPS) protocol and then assigned to either voluntary exercise, forced exercise, or control conditions. Both exercise modalities were found to attenuate anxiety-like behaviors and improve inflammatory gene expression, with voluntary exercise showing greater behavioral improvements.
Abstract
<h4>Background</h4>Post-traumatic stress disorder (PTSD) arises after traumatic or life-threatening events and involves persistent anxiety and altered stress responses. Physical exercise is a proposed non-pharmacological intervention, yet evidence comparing voluntary and forced exercise regarding their behavioral and biochemical effects in experimental PTSD models is still limited.<h4>Methods</h4>In this experimental study, adult male rats were subjected to a single prolonged stress (SPS) protocol to induce a PTSD-like phenotype and were subsequently assigned to voluntary exercise, forced exercise, or control conditions. Anxiety-like behaviors were evaluated using behavioral tests, including the open field test, elevated plus maze, and light-dark box. The hippocampal mRNA expression levels of inflammatory cytokines, including IL-1β, IL‑10, and TNF‑α, were quantified by reverse transcription polymerase chain reaction.<h4>Results</h4>Exposure to SPS induced a marked anxiety‑like behavioral phenotype, as evidenced by reduced exploration of anxiogenic zones across all behavioral paradigms, without significantly affecting general locomotor activity. SPS exposure was also associated with increased hippocampal expression of the pro‑inflammatory cytokines IL‑1β and TNF‑α, accompanied by reduced expression of the anti‑inflammatory cytokine IL‑10. Both voluntary and forced exercise attenuated SPS-induced anxiety-like behaviors and significantly improved hippocampal inflammatory gene expression. Voluntary exercise produced greater improvement across several behavioral measures. At the molecular level, both exercise modalities attenuated SPS-induced pro-inflammatory alterations, whereas voluntary exercise alone significantly restored the anti-inflammatory cytokine IL-10.<h4>Conclusion</h4>Both voluntary and forced exercise effectively attenuated SPS-induced anxiety-like behavior and hippocampal inflammatory dysregulation. Voluntary exercise demonstrated greater behavioral improvement across anxiety-related paradigms. Although only the VolExc group reached statistical significance relative to the SPS group for IL-10, direct comparison between VolExc and ForExc did not reveal a significant difference, indicating that molecular outcomes were broadly comparable between the two exercise modalities. These findings suggest that voluntary exercise may provide behavioral advantages following traumatic stress, although the two modalities were not statistically distinguishable from one another at the molecular level.
Background
This paper addresses the effects of physical exercise as a non-pharmacological intervention for post-traumatic stress disorder (PTSD), which is characterized by persistent anxiety and altered stress responses. Prior research has suggested that exercise may have beneficial effects on anxiety and inflammation, but comparisons between voluntary and forced exercise in PTSD models are limited. Understanding these differences could inform therapeutic strategies for managing PTSD symptoms.
Methods
The study involved adult male rats subjected to a single prolonged stress (SPS) protocol to induce PTSD-like symptoms. The rats were then assigned to three groups: voluntary exercise, forced exercise, or control. Anxiety-like behaviors were assessed using behavioral tests such as the open field test, elevated plus maze, and light-dark box. The expression levels of inflammatory cytokines in the hippocampus were measured using reverse transcription polymerase chain reaction.
Results
SPS exposure resulted in a marked anxiety-like behavioral phenotype, evidenced by reduced exploration of anxiogenic zones. Both voluntary and forced exercise significantly improved anxiety-like behaviors and hippocampal inflammatory gene expression. Voluntary exercise was associated with greater behavioral improvements, while both modalities attenuated pro-inflammatory changes.
Interpretation
The findings indicate that both voluntary and forced exercise can mitigate anxiety-like behaviors and inflammatory dysregulation following traumatic stress. However, while voluntary exercise showed greater behavioral benefits, the lack of significant differences in molecular outcomes between the two modalities suggests that both forms of exercise may be comparably effective at the biochemical level. The small sample size and reliance on a rodent model limit the generalizability of these results to human populations.
Key findings
- SPS exposure led to reduced exploration of anxiogenic zones across all behavioral paradigms, n=Not reported in abstract.
- Increased hippocampal expression of IL-1β and TNF-α was observed following SPS exposure, n=Not reported in abstract.
- Voluntary exercise significantly restored IL-10 expression compared to SPS group, n=Not reported in abstract.
- Both voluntary and forced exercise improved behavioral measures, but direct comparison did not reveal significant differences, n=Not reported in abstract.
Limitations
- rodent model may not fully translate to humans
- sample size not reported
- specific numeric findings not detailed in abstract