The cellular composition significantly affects the properties of platelet concentrates. In particular, leukocyte platelet concentrates due to the increased number of monocytes and granulocytes have increased levels of proinflammatory cytokines, which contribute to the destruction of extracellular matrix, reduce synthesis of its components and enhance inflammation in tissues. The purpose. To determine the blood cells number in leukocyte (L-PCP) or leukocyte-poor platelet-concentrated plasma (LP-PCP) and compare it with whole venous blood, plasma and platelet-poor plasma. Materials and methods. 20 L-PCP and 21 LP-PCP samples were obtained by double centrifugation from the venous blood of 30 donors aged 26 to 78 with local pathology of the musculoskeletal system. In the first stage, plasma was isolated after the separation of whole blood, and in the second stage, platelets were concentrated in a small volume of platelet-poor plasma. The number of blood cells in the test samples was determined by hematology analyzer.

Platelet-rich plasma (PRP) is plasma with high platelet count. Currently, PRP is used in many fields of medicine [1, 2, 9]. It is believed that the platelet count in PRP should be about 1 million per 1 μl, or 2-5 times higher than in whole blood of a healthy person, where their content is 150,000 to 450,000 per 1 μl. This platelet concentration is considered necessary for effective tissue regeneration. PRP is usually obtained from the patient's own blood (autologous PRP) [10]. There are many methods and techniques to obtain PRP [18, 21], which significantly complicates the development of its classification. The most commonly used classification is developed by D. Dohan Ehrenfest, who divided platelet concentrates by leukocyte concentration and fibrin content into 4 groups [11]. According to this classification, PRP is divided by the content of leukocytes into leukocyte-containing and pure. Leukocyte-containing PRP has a high concentration of leukocytes, pure PRP is characterized by their low content. Other classifications of platelet concentrates have been proposed, in particular by J. Magalon. It uses the number of platelets, the percentage of platelets and other cells in PRP. This classification takes into account the effectiveness of techniques and devices for platelet isolation [20]. TGF-β1 level in platelet-rich plasma in patients with diseases and injuries of the musculoskeletal system

In recent years, there is a growing interest in the application of regenerative medicine methods in the treatment of degenerative lesions of the musculoskeletal system. Gonarthrosis is one of the most common reasons for patients to visit to orthopedic traumatologists. The purpose of the study was to evaluate the quality of life in patients with gonarthrosis at different stages after application of leukocyte-rich platelet-rich plasma (LR-PRP) and leukocyte-poor platelet-rich plasma (LP-PRP). Materials and methods. The results of the treatment of 48 patients with gonarthrosis stages 1-3 according to Kellgren-Lawrence after intra-articularly injection of LR-PRP or LP-PRP were compared. The quality of life questionnaires were used: visual analogue scale (VAS), Lysholm Knee Score (LKS) and Oxford Knee Score (OKS) before treatment, after the first injection, every 2 weeks before the end of treatment and every 3 months for 1 year. Results. Evaluation of the treatment results obtained at stages 1 and 2 of gonarthrosis showed a positive result for both groups of patients during 12 months of follow-up and at stage 3 a significant improvement was achieved for up to 6 months. There was no significant difference between the results of LR-PRP and LP-PRP for 9-12 months. When using LP-PRP, the dynamics of quality of life during the year was smoother and more gradual, without periods of regression, while for LR-PRP there was a clear significant short-term reduction in the treatment effect for about 6 months compared to both baseline and values of the previous period at 1 and 2 stages gonarthrosis with further improvement and a stable positive effect for up to 12 months. Conclusions. The application of platelet-rich plasma improved the quality of life for 12 months in patients with stage 1-2 gonarthrosis and for 6 months at stage 3. The obtained positive results substantiate the need for further research to determine the prospects for the application of platelet-rich plasma in the complex treatment of knee osteoarthritis compared to other methods.