Effectiveness of local MSC derived from placenta and their conditioned medium in local radiation burn

Background & Aim To study the effect of mesenchymal stem cells (MSC) derived from placenta human and their conditioned medium concentrate on skin regenerative processes in laboratory animals with local radiation burn (LRB). Methods, Results & Conclusion The study used 80 laboratory animals (males Wistar aged 8-12 weeks and weighing of 210.0±30,0 g), randomized into 4 groups (20 animals each): control (C) - without therapy; control with the injection of the concentrate of the culture medium (CM); injection of MSC (P); the injection of the PCM. The dose of therapy was of 2 million cells per 1 kg three times at on the 1, 14 and 21 days after radiation exposure. Histological and immunohistochemical (CD31, CD68, VEGF, PGP9.5, Ki67, FVIII, collagen I and III, TIMP2, MMP 2 and 9) studies were performed. LRB was modeled on an x-ray unit at a dose of 110 Gy. MSC were cultured according to standard methods 3-5 passage, carried out fence of the conditioned medium and concentrated it in 10 times. An the LRB was recorded in all groups of animals on day 14 of the experiment. The LRB in the PCM group was less than 6.7 times compared with the control group. Complete healing of the skin was observed on the 112th day in the PCM group in 60%, in the SM group in 40%, in the P group in 20%, and in the C group there were no animals. Histological studies showed a decrease in inflammatory processes, the presence of primordia of hair follicles, and proliferation of microvasculature in the PCM group, in contrast to other groups in which these changes were not so noticeable. In all groups, the regenerative potential of cells in the LRB is reduced, which is confirmed by immunohistochemical data. An increase in the expression of MMP 2 and 9, TIMP 2, collagen I and III, and the number of CD68 macrophages was observed in the PCM group on the 112th day, which probably indicates an increase in the rate of scarring and healing of the wound surface. Thus, the use of the PCM in severe LRB in laboratory animals accelerates the transition of the wound process to the stage of regeneration and epithelization. It is interesting that in one of the control groups, when using a CM, a significant decrease in the area of the wound was observed in comparison with other groups throughout the observation period. However, the analysis of histological and immunohistochemical studies does not allow to state definitely about the effectiveness of this type of therapy.