Platelet-rich plasma (PRP) is an autologous concentration of human platelets in plasma. Through degranulation of the alpha granules in platelets, PRP can secrete various growth factors, including platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), hepatocyte growth factor (HGF), and transforming growth factor (TGF), which have been documented to initiate wound healing and promote the proliferation and transformation of endothelial cells and pericytes into endothelial sprouts.
The roles of PRP for the treatment of hair growth have been reported in many recent researches. Uebel et al. have found that platelet plasma growth factors increase the yield of follicular units in male pattern baldness surgery. Recent work has shown that PRP increases the proliferation of dermal papilla cells and induce faster telogen-to-anagen transition using in vivo and in vitro models. Another study has indicated that PRP promotes the hair follicle reconstitution and significantly shorten the time of hair formation.
Both the PRP and platelet-poor plasma (PPP) include the full complement of coagulation proteins. In the present study, the influence of PRP and PPP on hair growth in C57BL/6 mice was investigated. The hypothesis was that PRP had a positive effect on hair length growth and increase of the number of hair follicles.
Experimental animals
Totally 50 healthy C57BL/6 male mice (6 weeks old, 20 ± 2 g) were obtained from the Center of Laboratory Animals, Hangzhou Normal University (Hangzhou, China). Animals were fed the same food and maintained in a constant environment under a 12:12-h light–dark cycle. After 1 week of acclimatization, mice were randomly divided into three groups: PRP group (n = 10), PPP group (n = 10), and control group (n = 10).
The study protocol was approved by the institutional ethics committee of animal research under the Law of Animal Research and Statutory Regulations in China.
Hair length measurement
At 8, 13, and 18 days after the last injection, 10 hairs in each mouse were randomly selected in the target area. Hair length measurements were carried out in three fields using an electron microscope, and their average was expressed as millimeters. The elongated or damaged hairs were excluded.
Hematoxylin and eosin (HE) staining
Dorsal skin samples were excised at 18 days after the third injection. Then samples were fixed in 10% neutral buffered formalin, embedded in paraffin, and cut into 4 μm. The sections were baked for 4 h for deparaffinization at 65 °C, dipped into gradient ethanol, and then stained with hematoxylin for 5 min. After differentiated in 1% hydrochloric acid alcohol, the sections were incubated in ammonia water, stained with eosin, and rinsed with distilled water. Finally, the sections were dehydrated with gradient ethanol, cleared with xylene, mounted with neutral resin, and observed using a light microscopy (Olympus, Tokyo, Japan).
Post time: Oct-12-2022