Abstract:

Objective   To study expression of early growth response protein-1(EGR-1) in rats′ skin after 1064nm Nd∶YAG laser treatment and its relationship with and non-ablative photo-rejuvenation. Methods   The Q-switched 1064nm Nd∶YAG laser was applied to irradiate rats′ dorsal skins 4 times at intervals of 2 days after rats′ dorsal fur molted. Rats′ dorsal skin samples were taken to measure the thickness of the dermis and collagen bundles with HE staining and to measure the hydroxyproline content by the alkaline hydrolysis method on days 14 and 30 after irradiation.  Rats′ dorsal skin samples were taken to measure expression of EGR-1 by the immunohistochemical method on days 1 and 7 after irradiation. Results   The dermis and collagen bundles were thicker and the content of hydroxyproline was higher in the experimental rats′ skin than in the control group (P<0.05). The immunohistochemical result indicated that EGR-1 was upregulated in the skin on day 1 after irradiation(P<0.01). Expression of EGR-1 in the skin on day 7 after irradiation had no significant difference compared with the control group(P＞0.05). Conclusion   Up-regulated expression of EGR-1 is closely related to non-ablative photo-rejuvenation.

Key words: Early growth response protein-1; Laser; Collagen; Hydroxyproline; Non-ablative photorejuvenation