Increase in blood bradykinin concentration after eccentric weight-training exercise in men

Area of Science:

• Exercise Physiology
• Biochemistry
• Inflammation Research

Background:

• Eccentric exercise causes muscle damage and inflammation.
• Bradykinin (BK) and des-Arg(9)-bradykinin (des-Arg(9)-BK) are peptides involved in inflammatory processes.
• The role of BK and des-Arg(9)-BK in exercise-induced muscle damage is not fully understood.

Purpose of the Study:

• To investigate the presence of bradykinin (BK) and des-Arg(9)-bradykinin (des-Arg(9)-BK) in the blood following eccentric exercise.
• To explore the potential involvement of BK in exercise-induced muscle inflammation.

Main Methods:

• 13 male subjects performed eccentric exercise (leg presses).
• Blood samples were collected pre-exercise and at various time points post-exercise.
• Concentrations of BK and des-Arg(9)-BK were measured using competitive enzyme immunoassays.
• Serum creatine kinase activity was measured to confirm muscle damage.

Main Results:

• Eccentric exercise led to significant muscle damage and inflammation, indicated by increased creatine kinase levels and pain.
• Blood concentrations of des-Arg(9)-BK did not change significantly after exercise.
• A significant increase in blood BK concentration was observed immediately after exercise.
• BK levels returned to baseline within 48 hours post-exercise.

Conclusions:

• Bradykinin (BK) levels rise immediately after eccentric exercise.
• The increase in BK suggests it may mediate inflammatory processes related to exercise-induced muscle damage.
• Des-Arg(9)-bradykinin does not appear to be involved in this specific exercise response.