The Effect Of Platelet-rich Fibrin On Chronic Refractory Wound Healing

Objective:To investigate the clinical effect of Platelet-Rich Fibrin(PRF)on chronic refractory wounds.Methods:Forty patients with chronic refractory wounds admitted to the Department of Burns and Plastic Surgery,Affiliated Hospital of Chengde Medical College from September 2020 to December 2022 were selected.The patients were randomly divided into PRF group(n = 20)and control group(n = 20).Patients and their families were informed of the purpose of this study enrollment and signed an informed consent form.After the necrotic tissue was removed,the preprepared autologous PRF gel was evenly covered on the wound,and then the wound was covered with vaseline gauze and sterile gauze in turn.The treatment course of the PRF group was 7 days,and the dressing was changed every other day,only the outer dressing was changed after each dressing change and disinfection.On the 7th day,all wound dressings were replaced and PRF was used to cover the wound again.Patients in control group were treated with wound debridement after iodophor disinfection,and the necrotic tissue of the wound was completely removed,and then the wound was covered with vaseline gauze and sterile gauze in turn.The wound dressing was changed every other day,and the wound growth was photographed and recorded.The basic information of patients such as age,gender and course of disease before admission were collected.The wound exudates were collected for bacterial culture before treatment,7 days and 14 days after treatment.The wound tissue was collected before treatment,7 days and 14 days after treatment,and HE staining was performed to observe the changes of inflammatory response,leukocyte infiltration,and tissue fibrosis.C-Reactive Protein(CRP)level was detected by rate nephelometry,Procalcitonin(PCT)was detected by ELISA+immunofluorescence,and Interleukin-6(IL-6)was detected by electrochemiluminescence.IL-6)and White Blood Cell(WBC)levels;The levels of CD4+T cells and CD8+T cells and the ratio of CD4+T/CD8+T cells in the blood of patients before and 7 days after treatment were compared by flow cytometry.The 30-day healing rate and hospitalization time of the two groups were recorded,and the healing effect of the two groups was compared.Immunohistochemical staining of CD34 and VEGF in the wound tissue was performed before treatment and on the 7th and 14 th day after treatment to observe the degree of inflammatory infiltration,vascularization,and fibrosis in the wound tissue before and after treatment.The expression of VEGF m RNA and TGF-β m RNA in wound tissue was detected by q RT-PCR before treatment and on the 7th day after treatment to detect the effect of PRF on growth factors in wound tissue.SPSS 25.0 statistical software was used to analyze the data.Results:In this study,there was no significant difference in gender,age and course of disease before admission between the two groups(P> 0.05).Before treatment,the positive rates of bacterial culture of wounds in PRF group and control group were 85% and 80%,respectively,and the difference was not statistically significant(P> 0.05).On the 7th day after treatment,the positive rate of wound bacterial culture was 55% in PRF patients and 75% in control group,and the difference was not statistically significant(P> 0.05).On the 14 th day after treatment,the positive rates of wound bacterial culture in the PRF group and the control group were15% and 50%,respectively,and the difference between the two groups was statistically significant(P<0.05).HE staining showed that before treatment,a large number of inflammatory cells infiltrated the wound tissue of the two groups,and only a small number of blood vessels could be seen.On the 7th and 14 th day after treatment,the degree of inflammatory infiltration in the PRF group was significantly improved,and more neovascularization was observed.On the 7th day after treatment,the degree of inflammatory cell infiltration in the PRF group was less than that in the control group,and more neovascularization was observed.After 14 days of treatment,epithelial hyperplasia and new skin appendages appeared in the PRF group,while more neovascularization and some inflammatory cell infiltration were still seen in the control group.There was no significant difference in the measurement of inflammatory indexes between the two groups before treatment(P >0.05).On the 7th and 14 th day after treatment,the inflammatory indexes of the two groups decreased significantly compared with those before treatment.The levels of WBC,CRP,IL-6 and PCT in the PRF group decreased more significantly than those in the control group,with statistically significant differences(P<0.05).There was no significant difference in CD4+T cells,CD8+T cells and CD4+/CD8+ ratio between the two groups before treatment(P> 0.05).On the 7th day after treatment,compared with before treatment,CD4+T and CD4+/CD8+ ratio increased,CD8+T cells decreased in both groups.There were significant differences in CD4+T cells,CD8+T cells and CD4+/CD8+ ratio between the two groups(P<0.05).The 30-day cure rate of PRF group and control group was 65% and 30%,respectively(P=0.027 < 0.05).The average length of hospital stay was 32.75±12.72 in the PRF group and 45.80±18.06 in the control group(P=0.012<0.05),and the difference was statistically significant.Immunohistochemical staining showed that before treatment,the expression of positive cells in the wound tissue of the two groups was less.On the 7th and 14 th day after treatment,the positive expression cells of CD34/VEGF in the PRF group were more than those in the control group,which confirmed that the neovascularization ability of the wound tissue was enhanced after PRF treatment,so the positive expression cells were more.The granulation fibrosis and epithelialization of the wound in the PRF group were earlier than those in the control group.Before treatment,there was no significant difference in the relative m RNA expression of VEGF and TGF-β between the two groups(P> 0.05).On the 7th day after treatment,the average relative expression of VEGF m RNA in the PRF group and the control group was(3.990±0.518)and(1.023±0.227),respectively,and the difference between the two groups was statistically significant(P<0.05).The average relative expression of TGF-β m RNA was(2.823±1.605)and(1.012±0.404),respectively,with statistically significant difference(P<0.05).Conclusion:(1)The application of PRF in chronic refractory wounds is beneficial to reduce the positive rate of bacterial culture and reduce the inflammatory response of wounds.(2)The application of PRF in chronic refractory wounds is conducive to wound angiogenesis,local microvascular formation,and improvement of local microcirculation.(3)The application of PRF in chronic refractory wounds is conducive to the formation of granulation tissue,gradually forming a fibrotic barrier,and creating conditions for wound healing.