Research on combination of PRP, PRF and adipose-derived stem cells for wound healing of chronic skin ulcer

Objective To investigate the effects of combination of PRP, PRF and adipose-derived stem cells(ADSC) for wound healing of chronic skin ulcer, and provide evidences for clinical application. Methods Twenty-four SD rats aged 6-8 weeks were used in this study. 5 grams of groin adipose tissue were derived from each rat. After collagenase digestion, mesenchyma stem cells derived from adipose tissue(ADSCs) were determined by immunocytochemical method and flow cytometry. After continuous culturing, the 3 th passage of ADSCs in good condition was prepared for transplantation. Ten milliliters of whole blood were extracted from one rat for making PRP and PRF backup. Full thickness skin defect model with six wounds with an area of 1.5 cm*1.5 cm on each side of the spine on the back was established in rats after anesthesia. Then the rats were randomly divided into six groups. Skin wounds were injected with PRF combining ADSC in group A,PRF in group B,ADSC in group C,ADSC combining PRP in group D, PRP in group E, and same amount of normal saline(NS) in group F. Histological analysis was performed to evaluate the velocity and the quality of the wound healing 7 days, 14 days, 21 days and 28 days after treatment, and comparing the regeneration of epidermis, corium, fibroblast, blood vessel and skin appendages respectively. Results The woulds in each group healed well, without symptoms of infection. Skin wounds were almost healed in 21 days, and no significant difference in healing velocity was found among these groups. There were no apparent inflammatory cells in 7 days. The wounds were filled with granulation formed by proliferation of connective tissue with visible new blood capillary and repair cells like fibroblast. Epidermis grew out and became thick, and gradually grew to the wounds, with active proliferation of re-epithelization. Re-epithelization was completed in 14 days, with granulation tissue covered by epidermis and fibrosis showing a significant increase in collagenous fiber, and visible skin appendages like new hair follicle, glandula sebacea, sweat gland and corneum. Appendages like hair follicle, glandula sebacea, sweat gland and corneum increased in 21 days, and granulation tissue gradually formed scar tissue and entered remodeling phase. There was no significant changes from 21 days to 28 days, and the tissues were entering a long remodeling phase. Healing status: Group D, A and C could be observed with more complete epidermis, new blood vessel and new hair follicle. Among them, Group D was most significant, while group A, C, E, B successively and group F had the slowest epidermal migration and the least new hair follicle. The velocity and the quality of these groups were as follows: D>A>C>E>B>F, indicating that ADSC combining PRP can improve quality in wound healing of skin ulcer effectively.Conclusions After the general and pathological observation on the effects, the velocity and the quality for the skin ulcer healing of SD rats on the back were as follows: ADSC+PRP>ADSC+PRF>ADSC>PRP>PRF>NS, indicating that PRP or PRF combining ADSC can improve quality in wound healing of skin ulcer effectively.