Platelet rich plasma and other blood separation products hav

Platelet-rich plasma and other blood separation products have been used in human and veterinary medicine for over 20years. Numerous studies have proved the therapeutic effect of these products resulting from biological activity of the growth factors contained in platelets. Platelets are known to contain both specific and non-specific growth factors initiating mitogenesis and connective tissue regeneration. The most important of them are the platelet-derived growth factor (PDGF), the transforming growth factor (TGF-β), the vascular endothelial growth factor (VEGF), the epithelial growth factor (EGF), the fibroblast growth factor (FGF) and the insulin-like growth factor (IGF) [14]. Platelet-rich plasma gel and its derivative, platelet gel, are widely used for healing bone and soft tissues in restorative and reconstructive surgery, dentistry, traumatology and orthopedics [15].
Materials and equipment Materials based on CoPA nanofibers were obtained by the method described in Ref. [5]. Chitin nanofibers containing PEO and orthopox nanofibrils were obtained by electrospinning. The method for producing chitosan nanofibers and the properties of the materials based on them are given in Ref. [12]. The wound dressing was fabricated by electrospinning chitosan composite nanofibers containing 10wt.% chitin nanofibrils onto a surface of a porous CoPA nanofiber film. The thickness of the CoPA nanofiber layer amounted to 150µm, and that of the chitosan nanofiber layer to 50µm. The nanofibers were spinned using a NANON-01 system (Japan). The voltage U = 18kV was used, while the distance between the electrodes was 0.15m. Autologous blood separation products were used to intensify tissue reconstruction. Platelet-rich plasma was obtained by double centrifugation of 80ml of peripheral blood, and was then activated by adding autologous thrombin and a 10% calcium chloride in order to produce platelet gel (Fig. 1) [16]. The nanofiber-based composite wound dressings were tested on degloved skin flaps. A technique for obtaining model wounds of the skin and the subjacent soft tissues from small laboratory animals (rats) has been developed for this purpose. A scalpel incision was made to the back of the animal, and the skin was then separated from the superficial fascia using surgical scissors and forceps. The cutaneous edges of the wound were attached to the deep fascia by nodal musculocutaneous inverting sutures (Fig. 2). The animals received inhalation anesthesia with ether. This technique prevents the wounds from closing prematurely due to primary intention and allows to reliably evaluate the effectiveness of the healing method. The experiment was conducted on 18 male Wistar-Kyoto rats, each weighing 200–250g. The animals were divided into two groups, the control and the experimental. There were nine animals in each group. After modeling, full-layer mechanical skin wounds (covering 10% of the animal\'s body), chitosan-copolyamide dressings were applied to the wound surface for the animals in the experimental group. The rats were observed for 4weeks. A morphological examination of the newly-formed scar tissue was carried out after 28days of observation; the animals were withdrawn from the experiment and tissue samples were collected from the area of the wound. Samples were fixed with a 10% solution of phosphate-buffered neutral formalin (pH= 7.4) for 24h, then dehydrated in ethanol solutions with increasing concentrations and embedded in paraffin blocks. The 5-µm-thick paraffin sections were stained with hematoxylin and eosin (Bio-Optica, Italy). A Leica DM750 microscope (Germany) was used for microscopic analysis and image recording.
Experimental results and discussion Monitoring the control group of the rats revealed an 11% mortality rate with suppurative complications in 100% of cases; a vast accumulation of pus under the eschar was observed in 11% of cases (Fig. 3a). A histological examination of scar tissue (Fig. 4a) uncovered the presence of a large amount of capillary vessels and a dense infiltrate.