Can Exercise Slow or Prevent Vision Loss?

The “Voluntary Exercise Suppresses Choroidal Neovascularization in Mice” article in Retinal Cell Biology, May 2020 discusses a study conducted to determine the impact of voluntary exercise on choroidal neovascularization (CNV) in mice. CNV is the formation of abnormal blood vessels in the choroid layer of the eye and is associated with various vision-threatening diseases, including age-related macular degeneration (AMD). The researchers aimed to investigate whether voluntary exercise could influence the development and progression of CNV lesions in mice.

Study Design

The study involved using C57BL/6J mice, which were divided into groups with or without access to running wheels. The mice were subjected to laser injury to induce CNV. The effect of voluntary exercise on CNV was evaluated by comparing CNV volumes between exercise-trained mice and sedentary mice.

Results

The study revealed that mice that had undergone voluntary exercise showed a significant reduction in CNV volume compared to sedentary mice. In the first study, exercise-trained mice had a 45% reduction in CNV volume. A replication study also demonstrated a 32% reduction. When combined, voluntary exercise was found to reduce CNV by 41%.

Sex and Distance

The study found that the reduction in CNV volume due to exercise was consistent between male and female mice. However, the daily distance traveled by the mice did not correlate with the size of CNV lesions, suggesting that the effect of exercise might not be solely determined by the distance covered.

Post-Injury Exercise

The researchers investigated the impact of exercise undertaken after the laser injury (post-injury exercise). They found that post-injury exercise did not significantly reduce CNV size. This indicated that exercise preconditioning before the onset of CNV might be necessary to achieve positive effects.

Immune Response

The study observed that exercise-trained mice exhibited lower levels of F4/80+ macrophage staining and reduced expression of cytokines associated with angiogenesis. This suggests that exercise might have immunomodulatory effects that influence CNV development.

Discussion and Implications

The study’s findings align with epidemiological studies suggesting that exercise has beneficial effects on AMD-related pathologies. However, the dose-effect of exercise was modest and required preconditioning. The mechanisms by which exercise influences CNV and the molecular mediators involved need further investigation.

Clinical Relevance

The study suggests that physical activity could be a low-cost and noninvasive approach to potentially prevent eye diseases like AMD by influencing CNV development. However, the study acknowledges the limitations of using mice models and emphasizes the need for controlled clinical trials to establish the impact of exercise on human CNV.

Conclusion

This study provides experimental evidence that voluntary exercise might have a positive influence on choroidal neovascularization in mice. While the mechanisms behind this effect require further exploration, the study suggests that physical activity could be a beneficial lifestyle factor in preventing vision-threatening eye diseases.

For full research article visit: https://iovs.arvojournals.org/article.aspx?articleid=2766252