Apoptosis and antioxidant status are influenced by age and exercise training in horses.

The research investigates the effects of age and exercise on the rate of programmed cell death (apoptosis) and the antioxidant status in horses. Findings indicate that there is more cell death in older horses and less antioxidant glutathione. However, there were no significant differences in oxidative stress, as measured by levels of lipid hydroperoxide, between mature and aged horses, whilst physical training appeared to help the horses’ bodies prepare for intense physical activity.

Research Design and Methodology

• This study involved 13 standardbred mares divided into two groups: mature horses (8 horses, 12 ± 2 years old) and older horses (5 horses, 22 ± 2 years old).
• The horses were examined in a controlled environment with specific dietary and physical activity schedules.
• Both groups followed an 8-week training program of submaximal exercise. Their exercise performance was evaluated with a graded exercise test (GXT) before and after the training period.
• During these tests, blood samples were taken to measure cell apoptosis and antioxidant levels.

Key Findings

• There was no significant difference in lipid hydroperoxide concentration (a marker of oxidative stress) between the mature and older horses. The study found a correlation between lipid hydroperoxide and lactate levels, increasing during acute exercise.
• Overall, the level of glutathione (a key antioxidant) decreased after the exercise training program in both horse groups.
• The level of apoptosis was lower in mature horses compared to older horses, suggesting older horses may have a compromised immune response during exercise.

Implications and Future Directions

• The results suggest that older horses may encounter more cell death and have reduced antioxidant levels, potentially compromising their immunity during exercise.
• Despite their age, the horses had similar levels of oxidative stress, indicating that both mature and older horses can handle the same level of exercise-induced oxidative stress.
• Physical training seemed beneficial for both horse groups as it helped to prepare the body for future intense physical activities.
• The decrease in glutathione after the 8-week training period could be an adaptive response to repeated bouts of physical exercise.
• The study points to the need for further research on the potential benefits of dietary supplementation for aged horses in mitigating apoptosis and antioxidant depletion.