Mechanism Study Of Platelet-rich Plasma Gel Promoting Wound Healing Of Deep Ⅱ Degree Burn In Rats

Objective: To observe the effect of platelet rich plasma gel on the treatment of deep second degree burn wounds in rats and its influence on inflammation control and macrophage phenotype of burn wounds,and to preliminarily discuss the relevant mechanism of promoting burn wound healing.Methods: 1.Subjects: 30 SD rats,male,6-8 weeks old,about 180-220 g,SPF grade.Among them,12 were used to make platelet rich plasma gel,and the other 18 were used to establish deep second degree burn models.They were randomly assigned to an experimental group or a control group(9 in each group).In the experimental group,the wounds were smeared with platelet rich plasma gel and administered once every other day.The control group was covered with Vaseline gauze after applying the same amount of normal saline.The wound healing was observed on the 3rd,7th and 14 th day respectively.The wound healing rate was measured,the infiltration of inflammatory cells was observed by HE staining,the deposition of collagen was observed by Masson staining,the number of inducible nitric oxide synthase(i NOS)and CD206 positive cells were observed by immunohistochemistry,and the inflammatory factor TNF-α in the wound tissue was detected by fluorescence quantitative PCR(q PCR)And anti-inflammatory factors IL10 and TGF-β1The relative expression of m RNA.result:1.The wound healing rate of two groups of rats were increased with prolonged observation,in the experimental group 3,7,14 days healing rate is higher than the control group,the difference is statistically significant(P < 0.05).2.HE staining and high power microscopic observation showed that the number of inflammatory cells in the experimental group was lower than that in the control group on the 3rd,7th and 14 th day(P<0.05).3.Masson staining indicated a gradual increase in the deposition of collagen fibers in both groups with time.Three days after treatment,the collagen in the control group was less and sparsely distributed,while the collagen in the experimental group was thick and disordered.Seven days after treatment,the collagen fibers in each group were still in disorder,and the amount of collagen in the experimental group was more than that in the control group.On the 14 th day after treatment,collagen in the control group was disordered and fiber was broken.In the experimental group,most of them were arranged in order,and a few were arranged in disorder.4.Immunohistology showed that on the 3rd,7th and 14 th days after treatment,the number of i NOS labeled M1 macrophages in the experimental group was significantly lower than that in the control group,with a statistically significant difference(P<0.05).On the contrary,the number of M2 type macrophages labeled with CD206 in the experimental group was significantly higher than that in the control group(P<0.05).5.The q PCR showed that on the 3rd,7th and 14 th days after treatment,the relative expression of TNF-α m RNA in the experimental group was significantly lower than that of the control group(P<0.05).The relative expression of IL-10 m RNA was significantly higher than that of the control group(P<0.05).The relative expression of TGF-β1 m RNA in experimental group was significantly higher than that of the control group on the 3rd day(P<0.05).On the 7th and 14 th day,it was significantly lower than the control group(P<0.05).Conclusion:1.Platelet-rich plasma gel can inhibit the expression of inflammatory factor TNF-α,increase the expression of anti-inflammatory factors IL10 and TGF-β1,reduce the inflammatory reaction on the wound and promote collagen synthesis,which has a significant effect on promoting healing.2.Platelet-rich plasma gel may promote wound healing by promoting the transformation of wound macrophage phenotype from M1 to M2.