**Evaluation of the E**ff**ectiveness of Mesenchymal Stem Cells of the Placenta and Their Conditioned Medium in Local Radiation Injuries**

**Vitaliy Brunchukov <sup>1</sup> , Tatiana Astrelina 1,\* , Daria Usupzhanova <sup>1</sup> , Anna Rastorgueva <sup>1</sup> , Irina Kobzeva <sup>1</sup> , Victoria Nikitina <sup>1</sup> , Sergei Lishchuk <sup>1</sup> , Elena Dubova <sup>1</sup> , Konstantin Pavlov <sup>1</sup> , Valentin Brumberg <sup>1</sup> , Marc Benderitter <sup>2</sup> and Alexander Samoylov <sup>1</sup>**


Received: 21 September 2020; Accepted: 23 November 2020; Published: 29 November 2020

**Abstract:** Background: The search for an effective therapy for local radiation injuries (LRI) is urgent; one option is mesenchymal stem cells (MSC) derived from the placenta and their conditioned medium for the regenerative processes of the skin. Methods: We used 80 animals, randomly assigned to four groups: control (C) animals that did not receive therapy; control with the introduction of culture medium concentrate (CM); introduction of MSCs (PL); introduction of CMPL. LRI modeling was performed on an X-ray machine at a dose of 110 Gy. Histological and immunohistochemical tests were performed. Results: On the 112th day, the area of the open wound surface in the CMPL group was 6.7 times less than in the control group. Complete healing of the open wound surface of the skin in the CM group was observed in 40%, in CMPL 60%, in the PL group 20%, and in the C group there were no animals with a prolonged wound defect. A decrease in inflammatory processes was observed in the CMPL group. Conclusions: the use of a concentrate of conditioned MSCs (CMPL group) in severe LRI in laboratory animals accelerates the transition of the wound process to the stage of regeneration and epithelization.

**Keywords:** mesenchymal stem cells; local radiation injuries; conditioned medium; cell technologies; X-ray radiation; skin; placenta
