Specific immuno-extraction followed by enzymatic detection (SIEFED) of myeloperoxidase and mitochondrial complex I in muscular microbiopsies: preliminary results in endurance horses.

The research explores how intensive exercise in horses can lead to an increase in creatine kinase and stimulate neutrophils to release an enzyme called myeloperoxidase (MPO) into the bloodstream. The study seeks to understand if MPO is found in horse muscles and if the oxidizing activity of neutrophils can affect muscle tissues and mitochondrial activity, using new detection methods called Specific immuno-extraction followed by enzymatic detection (SIEFED).

Objectives and Methodology

• The main goal of the study was to utilize the SIEFED methods to measure the normal range of MPO and mitochondrial complex I (MCI) activities in horse muscular micro-biopsies. Also, it aimed to analyze how these activities may change due to endurance races.
• To achieve this, forty-six micro-biopsies were taken from 8 endurance Arabian horses’ triceps brachii or gluteus medius muscles. The MPO and MCI activities were then measured in these muscle extracts using enzyme immunocapture assays or SIEFED methods.
• In addition, seven endurance horses were sampled in the triceps brachii muscle before and after a 120 km endurance race.

Findings

• The study found that the active MPO concentration and MCI activity in the 46 micro-biopsies from 8 horses showed mean values of 21 ± 14 ng/mg proteins and 0.0172 ± 0.0066 mOD/min/μg proteins, respectively. No significant difference was noted between the two muscles.
• Three out of the seven horses sampled after the race showed a significant increase in muscle MPO activity and a large decrease in MCI activity, accompanied with a high mean plasma CK level.
• The MPO and MCI activities remained unchanged in the remaining four horses, and only a moderate increase in plasma CK levels was seen.

Conclusion

• The initial observations of this study indicate a potential connection between MPO activity and mitochondrial functions. More extensive testing may be required to establish a solid correlation between these two areas.