## 1 Introduction
The above mentioned process requires close cooperation of components of the ECM, including glycosaminoglycans, such as heparan sulfates (HS) and hyaluron (HA), during all phases of the healing process [14; 15; 16; 17]. GAGs--present in all mammalian tissues--representing negatively charged, unbranched, linear molecules, previously known as mucopolysaccharides, consist of repeating disaccharide units. GAGs (excluding HA) co-create in animal tissue PGs, in the structure of which GAGs are covalently linked to PGs' core proteins [18]. The molecules in question play key roles encompassing, among others, modulation of migratory activity of cells, cell proliferative activity, and cell differentiation activity and orchestrate ECM assembly by shaping its structure and mechanical properties as a result of interactions with fibrous proteins, such as collagen and elastin [18; 19; 20; 21; 22; 23; 24]. In addition, they play an important role in maintaining homeostasis, e.g., by controlling and participating in wound healing processes or cell-cell interactions [25]. Moreover, the heteropolysaccharides in question also actively participate in selected metabolic \"phenomena\", such as bone tissue mineralization or blood coagulation. Both free GAGs and PGs are ubiquitously distributed throughout mammalian ECMs [20]. HS and heparin, co-creating the family of heparan sulfate proteoglycans (HSPGs), are expressed on cellular membranes within secretory structures as well as within the extracellular milieu. Degradation of HSPGs is responsible for the occurrence of free HS, mainly in lysosomes, in the cell nucleus while simultaneously contributing to the formation of fundamental elements of the ECM, such as basement membranes [17; 18; 21; 26; 27; 28; 29; 30; 31]. HSPGs take part in cell-cell interactions and cell-ECM interactions, resulting in migration and adhesion of cells to ECM components, such as fibronectin, laminin, collagen types I, III, V, XV, and XVIII [32; 33]. PGs of the mentioned type modulate, among others, white blood cells' infiltration of the damaged tissue, triggering the sequence of events contributing to wound healing [30]. Heparan sulfate GAGs, through their presence, protect the vascular endothelium against damage [18; 34; 35]. HS, moreover, demonstrates anticoagulant and antiproliferative effects and stimulates the activity of lipoprotein lipase [22]. HS glycans, through interactions with ECM glycoproteins and tissue growth influencing molecules, modulate cellular division, new blood vessel formation, embryogenesis, and cancer development [36; 37]. Both heparan sulfate and heparin PGs play a role in the development of inflammation that occurs in the course of tissue damage. They are an indicator of the effectiveness of the wound healing process. In the initial phase of wound healing, their content increases, which is crucial in the early phase of repairing tissue damage [8]. HA is a naturally occurring, unbranched polysaccharide chain composed of repeating disaccharide units [18; 38; 39; 40; 41]. The mentioned glycan occurs in all human body fluids, as well as in tissues. The highest HA accumulation can be found, among others, in the inner skin layer (between epidermis and subcutaneous tissue), cartilaginous tissue, viscous fluid of a joint space, the largest intraocular component, the tube-like flexible compartment connecting the fetus and placenta, renal tissue, muscular tissue, the lymphoid system, mucosa, and cerebral tissue [18; 21; 38; 40; 42; 43; 44]. The basic function of HA is to bind and retain water in the intercellular spaces, which increases the tissues' resistance to mechanical injuries. Together with chondro sulfate, HA provides tissues with strength and elasticity [27]. HA is also implicated in the regulation of cell adherence and movement and exhibits antiphlogistic and free radical scavenging activity [18; 19; 26; 45; 46; 47]. It is also used as a marker of some diseases (including rheumat and cancer) [18; 26; 47].