Comparison of the Effects of Possible Mechanical Stimuli on the Rate of Biochemical Reactions

Abstract

The aim of this work is to address the question of what constitutes a mechanical stimulation of biochemical reactions in general and further to compare the importance of the two possible mechanical stimulations: shear rate and the rate of volume variation. Using linear nonequilibrium thermodynamics, the Curie principle (the relation for coupling phenomena) is retrieved for a phenomenological relation for a scalar flux in an isotropic system. From these phenomenological relations for the rate of chemical reaction, it is established that the only scalar quantity related to the rate of deformation tensor D that cannot be neglected is the rate of volume variation D((1)). This leads us to the conclusion that, although tissues are exposed to all variety of mechanical factors: straining, shear, pressure, and even dynamic electric fields, the volume variation rate D((1)) is the most important mechanical stimulus driving the processes in them.

Feasible Simulation of Diseases Related to Bone Remodelling and of Their Treatment

“…The affinity and chemical potential are (in simpler cases) proportional to the logarithm of the molar concentration of the involved substances (deGroot and Mazur, 1962). Here we actually use a modified version of this law of mass action with the additional effect of dynamic loading on the interaction rates (Klika, 2010;Klika and Maršík, 2009). The law of mass action is frequently used in modelling biological processes (Keener and Sneyd, 2009).…”

“…It is worth mentioning that Heřt referred to this fact in his observations more than 35 years ago (Heřt et al, 1972). From the phenomenological relations for the rate of chemical reaction based on classical irreversible thermodynamics including coupling with mechanical processes, it was shown that, although tissues are exposed to all variety of mechanical factors: straining, shear, pressure, and even dynamic electric fields, the volume variation rate is the most important mechanical stimulus driving the processes in them (Klika, 2010). However, we believe that shear rate might be important for triggering the process.…”

“…In our previous work, the influence of mechanical stimulation on (chemical) interactions in general was studied and it was shown how to comprise this effect into a model of studied biochemical processes (Klika and Maršík, 2009;Klika, 2010). These findings were used to describe the bone remodelling phenomenon Maršík et al, 2010).…”

“…A new model for RANKL-RANK-OPG chain kinetics has been formulated and added (Klika et al, 2010) to the mentioned model of bone remodelling . This section is being RANKL is a ligand molecule and binds to RANK forming a bond, here noted as and its molar concentration as [RR], between osteoblasts and precursors of osteoclasts.…”

“…However, we believe that shear rate might be important for triggering the process. (for details see (Klika, 2010;Klika and Maršík, 2009)). Thus, in the presented manuscript, the mechanical stimulation of bone remodelling was assumed to be proportional to rate of volume change.…”