The adverse effect of ciprofloxacin treatment can be related to the increased thermal stability of monomeric actin

Abstract Actin is a major component of all sarcomere and cytoskeletal systems and thus plays a crucial role in muscle and cellular movement. The molecular dynamics of actomyosin complexes are obtaining the central machinery of force generation during contraction. Nalidixic acid, discovered in 1962—the primary compound of the quinolone, fluoroquinolone-type antibiotics—in the forms of its improved derivatives are still widely used today. One of the most commonly used drugs in this class is ciprofloxacin (CF). It was observed that after the use of these drugs—during longer or shorter administration or even after their use—several side effects such as muscle pain (myalgia), muscle spasms, and muscle atrophy also occur, and muscle damage and rupture may be associated with muscle cell death (rhabdomyolysis). In medical cases, muscle weakness after CF treatment can be related to the CF-actin interaction. Here, we studied the effect of CF on skeletal muscle actin using differential scanning calorimetry (DSC). We obtained evident data that CF binding increases the structural stability of G actin and slightly weakens the F actin filaments. The stability change of actin in myofilaments can lead to the adverse effect of CF.