بررسی اثر Poly(I:C) در مقایسه با LPS در تحریک سلول های مزانشیمال برگرفته از مغز استخوان در ترمیم سوختگی درجه سه پوست موشی

Background & Aims: The positive effect of mesenchymal stem cells in healing of various types of tissue damage such as burn has been reported. The therapeutic potential effects of mesenchymal stem cells influenced by certain agonists from their surface called Toll like receptor (TLR) can be modified into proinflammatory and anti-inflamation phenotypes. It is believed that modification of phenotypes of mesenchymal stem cells can affect their therapeutic function. Therefore, the aim of this study was to assess the influence of Poly(I:C) (TLR3 agonist) versus LPS (TLR4 agonist) in stimulating mesenchymal stem cells and alteration of the therapeutic potential of these cells for the treatment of third-degree skin burns in mice which was performed at institute of Bio-technology, Urmia University, Urmia, Iran. Materials & Methods:&nbsp; Total 36 male mice aged 7-8 weeks with 25-30 gr average weights were selected. Based on burn standard method, a stainless-metal rod was heated to 100 in boiling water and burn wounds of 9 second duration were created on each mouse. Within an hour of burn induction, the mice were randomly assigned to four groups, control group with daily application of silver sulfadiazine gel, treatment 1 was treated by receiving subcutaneously 106 unstimulated mesenchymal cells, treatment 2 was treated by receiving subcutaneously 106 lipopolysaccharide (LPS)-stimulated mesenchymal cells, treatment3 was treated by receiving subcutaneously 106 Poly (I:C)-stimulated mesenchymal cells. Biopsies were taken from wounds and some normal tissues around it on days 7, 14 and 21 after burn induction. All samples were examined histopathologically by Hematoxilin-Eosin and masson trichrome stains in terms of thickness of the granulation tissue, tissue repair process, array of granulation tissue and deposition of collagen fibers in the repairing area. Checking normality test was processed using SPSS 18.0 Software (SPSS Inc, Chicago, IL, USA) and data then were analyzed using one-way ANOVA, Tukey and post hoc test. Results: Thickness of the granulation tissue on day 7 differed significantly between the control group and treatment 1 (P </ 007) as well as control group and the treatment 2 (P </ 001). Moreover, treatment 2 showed statistically significant difference for creating the most extensive granulation tissue compared with treatment 3 (P</002). Thickness of granulation tissue started to decrease since day 7 in all treatment groups but control with a more significant progress in treatment 2. The minimum thickness of the granulation tissue was observed for treatment 2 on day 21. The results from the hematoxylin & eosin and Masson's trichrome stained granulation tissues revealed collagen deposition develop in the repairing area Conclusion: Increased therapeutic potential of LPS -stimulated mesenchymal stem cells versus reduced therapeutic potential of Poly (I:C)-stimulated mesenchymal stem cells can be as a result of attaining the proinflammatory versus anti-inflammatory phenotype in mesenchymal stem cells in response to the respective agonists, respectively.