The Effect of Mechanical Loading or Hypokinesia on the Structures of the Extracellular Matrix and Functional Changes in Soft Tissues
Abstract
Physical forces influence living organisms and define the architecture and functionality of particular tissue segments. Some recent studies (Sarasa-Renedo and Chiquet, 2005; Maeda, 2011, etc.) have suggested that mechanical forces influence and maintain homeostasis in every living tissue, for example tendons, muscles, bones, etc.
There are even results showing higher importance of applied mechanical loading on the structural and functional parameters of an organism than the chemical, nutritional sufficiency. Due to the problematic determination of the direction of loading in a human body, the most mechanically tested and examined tissues are tendons, bones, muscles and vessels.
From a biomechanical point of view, biological materials are frequently considered as the viscoelastic, viscoplastic ones (Peterson & Bronzino, 2007). Classical modeling instruments are difficult to choose for analyzing the reaction of materials to mechanical loading, unloading – hypokinesia.
This is mainly caused by the non-homogenous, composite, anisotropic and highly adaptable characteristics of biological tissues. The understanding of microscopic changes, which occur while loading and unloading, is essential as the tissues are metazoan structures, thus the rheological properties highly depend on the supporting scaffold called the extracellular matrix (ECM).
The structure of the ECM influences the pathways through which the mechanical signals are transferred. This phenomenon is named mechanotransduction.
The signals are then perceived by cells and transformed into chemical signals. This phenomenon is called mechanosensitivity (Mecham, 2011).
According to the cyclic relationship between the ECM and cells, adequate mechanical loading is crucial for correct development and function of tissue.