Recombinant human collagen injection ameliorates skin photoaging via immunoregulation and collagen production

Abstract

Collagen, recognized as the primary structural component of human skin, is essential for preserving dermal integrity and function. Its progressive depletion has been closely associated with structural deterioration of the dermis and the visible signs of skin aging. Among current therapeutic strategies, the injection of exogenous collagen has been established as an effective method for alleviating aging-related skin changes. In the present study, a comprehensive evaluation was conducted to assess the injectability, cellular interactions, and photoaging repair efficacy of recombinant human collagen type III (RHC). The RHC solution was found to demonstrate favorable injectability and support the adhesion and chemotactic behavior of L929 cells, while also upregulating the expression of type I and type III collagen. In co-culture systems with lipopolysaccharide-stimulated macrophages, RHC treatment suppressed macrophage proliferation and reduced the production of proinflammatory cytokines, suggesting notable immunomodulatory properties. Upon intradermal injection of RHC into photoaged rat skin, an increased density of dermal collagen fibers was observed, accompanied by a more organized and uniform fiber arrangement. Additionally, hydroxyproline content and the expressions of collagen I and III were markedly elevated in the RHC group compared with the control and hyaluronic acid groups. Collectively, these findings suggest that RHC holds considerable promise as a therapeutic agent for both medical and cosmetic purposes targeting the restoration and maintenance of youthful skin characteristics.

Graphical Abstract