Effect Of Platelet-rich Plasma On Hair Follicle Growth In C57BL/6 Mice

Background: Platelet-rich plasma is a general term for plasma which conclude high concentration of platelets produced by whole blood after centrifugation.As platelet-rich plasma contains high concentration of platelets,which can produce growth factors after activation,they promote cell proliferation,migration,tissue repair and reconstruction.In addition to being widely used in cosmetic and plastic surgery,platelet-rich plasma is used in the treatment of chronic tendinitis,osteoarthritis,diabetic foot,burns and other traumatic diseases as well.Because of the increasing pressure of people's daily life,the incidence of androgenic alopecia and alopecia areata is constantly increasing,some studies have shown that injecting platelet-rich plasma can promote hair growth.However,there is no consensus on its effectiveness in clinic,and its mechanism is still unclear,this restricts the use of platelet-rich plasma in the treatment of various types of alopecia.The purpose of this study was to explore the effects of subcutaneous injection of platelet-rich plasma on hair growth and hair follicle cycle and explore its mechanism,so as to provide theoretical basis for clinical treatment of androgenic alopecia and alopecia areata.Objective: To investigate the effect of subcutaneous injection of platelet-rich plasma on hair follicle growth in C57BL/6 mice and its related mechanism.Methods: Twenty female C57BL/6 mice were divided into two group randomly.On the 0th day of the experiment,the dorsal hair was removed with a mixture of rosin and beeswax,and the hair follicle cycle of all mice was unified.The proliferating cells were labeled two times with 5-acetylene-2'-deoxyuridine nucleoside by intraperitoneal injection.After hair removal,PRP was injected subcutaneously at the depilation site of experimental group on the 1st,5th and 9th day,while the control group was injected with same dose of saline.Pictures were taken every 2 days to observe the growth of hair at the depilation site.On the 3rd,10 th and 18 th day of the experiment,three mice were killed respectively in each group.Skin tissues were taken for histological examination,the expression of Wnt10 b protein and its m RNA was detected by western blotting and polymerase chain reaction.On the third day of the experiment,the expression of Wnt10 b antibody in hair follicles was detected by histological immunofluorescence assay,at the same time,the proliferation of hair follicles cells was determined by 5-acetylene-2'deoxyuracil nucleoside labeling.Results: Skin photography showed that on day 0-6,the skin color of all mice were pink and no hair growth occurred during this period.From day 8,the skin color of the experimental group was darker,the hair density was higher and the growth rate was faster than that of the control group.The color of new hair of the experimental group and the control group was darker than that of the original hair.There was no significant difference in hair color between the two groups.Histological results showed that on the third day,the skin of the experimental group was thicker than the control group,and there was no significant difference in the number of hair follicles between the two groups.However,the hair follicles of the experimental group were at anagen III C,while those of the control group were at anagen II.On the tenth day,there were no significant difference in the number of hair follicles,skin thickness and the histological characteristics between the experimental group and the control group.On the 18 th day,the skin thickness and the number of hair follicles in the experimental group were less than those in the control group,and all hair follicles entered the telogen,while the hair follicles in the control group were still in the catagen.Western blotting and polymerase chain reaction showed that the expression of Wnt10 b in the experimental group was significantly higher than that in the control group at all time points(day 3,10,18).Tissue immunofluorescence and Ed U cell proliferation test confirmed that Wnt10 b and Ed U positive cells were expressed in hair matrix and inner root sheath in anagen in both experimental group and control group,but the signal intensity and average number of Ed U positive cells in each follicle in experimental group were higher than those in control group.Conclusion: Subcutaneous injection of platelet-rich plasma enhance the expression of Wnt10 b in tissues and hair follicles,activate the classical Wnt signaling pathway,promote the proliferation of hair matrix during the anagen of hair follicles,promote the transformation of hair follicles from telogen to anagen,accelerate the growth and the cycle speed of hair follicles,thus accelerate the growth of dorsal hair in mice.These characteristics make PRP a promising new choice for the treatment of androgenic alopecia,alopecia areata and other alopecia diseases.However,in this experiment,we have not found that PRP has the ability to prolong the anagen and shorten the telogen of hair follicles,and its effect on each stage of hair follicle cycle is still unclear.More animal experiments and clinical randomized controlled trials are needed to verify the safety and effectiveness of PRP in the treatment of androgenic alopecia and alopecia areata.