Synopsis ObjectivesSalidroside, the predominant component of a Chinese herbal medicine, Rhodiola rosea L., becomes an attractive bio-agent due to its multifunction. Although it is well proposed that this herbal medicine may have photoprotective effect according to the folk hearsay, the direct supportive experimental evidences linking the drug with skin ageing have rarely been reported so far. The study was conducted to investigate the photoprotective role of salidrosdie and its related mechanisms in vitro. MethodsFirst, a premature senescence model induced by UVB irradiation (250mJ cm(-2)) in human dermal fibroblasts (HDFs) was established, and senescent phenotypes were evaluated by cell morphology, cell proliferation, senescence-associated beta-galactosidase (SA--gal) activity and cell cycle distribution. Then the photoprotective effect of salidroside was investigated. Cells were pre-treated with various doses of salidroside (1, 5 and 10M) followed by the sublethal dosage of UVB exposure and then were harvested for various detections, including senescence-associated phenotypes and molecules, alteration of oxidative stress, matrix metalloproteinase-1 (MMP-1) secretion and inflammatory response. ResultsPre-treatment of salidroside dose dependently reversed the senescent state of HDFs induced by UVB as evidenced by elevated cell viability, decreased SA--gal activity and relieving of G1/G0 cell cycle arrest. UVB-induced increased protein expression of cyclin-dependent kinase (CDK) inhibitors p21(WAF1) and p16(INK4) was also repressed by salidrosdie treatment in a dose-dependent manner. Meanwhile, the increment of malondialdehyde (MDA) level in UVB-irradiated HDFs was inhibited upon salidroside treatment. Additionally, salidroside significantly attenuated UVB-induced synthesis of MMP-1 as well as the production of IL-6 and TNF- in HDFs. ConclusionOur data provided the evidences for the protective role of salidroside against UVB-induced premature senescence in HDFs probably via its anti-oxidative property and inhibition on production of MMP-1 and pro-inflammatory cytokines, which indicated its potential utilization as an active ingredient in the preparation of photoprotective formulation. Resume ObjectifsSalidroside, le compose predominant de une plante medicinale chinoise, Rhodiola rosea L., pourrait etre un agent biologique attractif en raison de sa multifonctionalite. Bien que ce medicament a base de plantes puisse avoir un effet de photo-protection selon l'oui-dire populaire, les preuves experimentales directes reliant le medicament au vieillissement de la peau ont ete rarement rapportees jusqu'ici. L'etude a ete menee pour etudier le role de photo-protection de salidroside et ses mecanismes connexes in vitro. MethodesD'abord, un modele de senescence prematuree induite par l'irradiation UVB (250mJ cm(-2)) dans les fibroblastes dermiques humains (HDFS) a ete cree et des phenotypes senescentes ont ete evaluee par la morphologie cellulaire, la proliferation cellulaire, l'activite beta-galactosidase (SA-- gal) associee a la senescence et la distribution du cycle cellulaire. Ensuite, on a etudie l'effet photo-protecteur de salidroside. Les cellules ont ete pretraitees avec diverses doses de salidroside (1, 5, 10M), suivie par la dose sous-letale de l'exposition aux UVB et puis ont ete recoltees pour differentes analyses, y compris des phenotypes et des molecules associes a la senescence, l'alteration du stress oxydatif, la secretion de la metalloproteinase matricielle -1 (MMP-1) et la reponse inflammatoire. ResultatsLe pretraitement au salidroside inverse l'etat de senescence des HDFS induits par les UVB de maniere dose-dependante comme en temoigne la viabilite cellulaire elevee, la diminution de l'activite -SA-gal, et de relaxation de l'arret du cycle cellulaire de G1/G0. L'expression augmentee des inhibiteurs proteine-kinase cycline-dependantes (CDK)p21WAF1 et p16INK4 induites par les UVB est egalement reprimee par le traitement au salidroside d'une maniere dependant de la dose. Pendant ce temps, l'augmentation du niveau de malondialdehyde (MDA) dans les HDFs UVB-irradies a ete inhibee par le traitement au salidroside. En outre, salidroside attenue significativement la synthese de MMP-1 induite par UVB, ainsi que la production d'IL-6 et TNF- dans HDFs. ConclusionNos donnees fournisssent les preuves pour le role de protection du salidroside contre la senescence prematuree induite par les rayons UVB dans les HDFs, probablement via sa propriete anti-oxydante et l'inhibition de la production de MMP-1 et des cytokines pro-inflammatoires, ce qui indique son utilisation potentielle en tant qu'ingredient actif dans la preparation d'une formulation de photo-protection.
