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Rejuvenative Efficacy and NF-κB Pathway-Dependent Mechanism of Human Platelet Lysate on Skin Aging

Background: Skin aging is an irreversible process associated with poor self-regenerative capability. Human platelet lysate (hPL) contains rich amounts of growth factors, benefiting tissue regeneration. To explore the anti-aging efficacy and mechanism of hPL on skin, this study employed nude mice and human dermal fibroblasts (HDFs) to perform in vitro and in vivo assays. 
 
Methods: Flow cytometry and ELISA were conducted for quality control of hPL. In vivo, skin texture grading, histopathological observation, immunofluorescence analysis, and SOD and MDA assays were conducted to determine the effects of hPL on epidermis and dermis of aged skin. In vitro, senescence-associated-beta-galactosidase (SA-β-Gal) staining, CCK-8 and wound healing assays were conducted to respectively evaluate the effects of hPL on senescent HDFs. Real time PCR and western blot were conducted to clarify the molecular mechanism of hPL. Moreover, a retrospective analysis was conducted to determine hPL′s efficacy and safety in clinic. 
 
Findings: The in vivo data showed that hPL exerted pro-regenerative and anti-oxidative effects on aged skin, resulting in reversing aged skin state. The in vitro data showed that hPL significantly promoted the proliferation and migration of HDFs and suppressed the inflammation, SASP secretion and senescence state of senescent HDFs through regulation of NF-κB signaling pathway. The NF-κB pathway-dependent mechanism of hPL was positively verified by using P65 siRNA and negatively verified by using prostratin. In clinic, hPL obviously rejuvenated the skin appearances of subjects without any adverse event. 
 
Interpretation: This study provided novel knowledge of hPL, making it an ideal therapeutic for skin aging treatment. 
 
Funding Information: This work was supported by National Natural Science Foundation of China (Grant No. 81774331 and No. 81671926), Zhejiang Provincial Basic Public Welfare Research Program (Grant No. LGF18H110003), Zhejiang Provincial Natural Science Foundation of China (Grant No. LQ20H150008) and Hangzhou Science and Technology Development Program (Grant No. 20180533B38). 
 
Declaration of Interests: The authors have declared that no competing interest exists. 
 
Ethics Approval Statement: All blood specimens used in this study were approved by 
Ethical Committee of the Zhejiang Chinese Medical University. Informed consent was obtained from healthy adult donors. 
 
All mice were treated in strict accordance with the China legislation on the use and care of laboratory animals. All experiments on the mice were approved by the Medical Norms and Ethics Committee of Zhejiang Chinese Medical University (Approval number SYXK:2018-0012, Zhejiang, China).