title: The protective effect of baicalin against UVB irradiation induced photoaging: an in vitro and in vivo study.
abstract: OBJECTIVE
  This study was aimed to evaluate the anti-photoaging effects of baicalin on Ultraviolet B (UVB)-induced photoaging in the dorsal skin of hairless mice and premature senescence in human dermal fibroblasts.
  
  
  METHODS
  We established in vivo and in vitro photoaging models by repeated exposures to UVB irradiation. By HE staining, masson staining, immunohistostaing and real-time RT-PCR, we analyzed epidermal thickness, collagen expression and the mRNA and protein levels of type I collagen, type III collagen, interstitial collagenase (MMP-1 and MMP-3) in UVB exposed dorsal mice skin. The aging condition in human dermal fibroblasts was determined by senescence-associated β-galactosidase (SA-β-gal) staining. Cell viability was determined using the Cell Counting Kit-8 (CCK-8). The G1 phase cell growth arrest was analyzed by flow cytometry. The senescence-related protein levels of p16INK-4a, p21WAF-1, and p53 and protein levels of phosphorylated histone H2AX were estimated by Western blotting.
  
  
  RESULTS
  Topically application of baicalin treatment reduced UVB-induced epidermal thickening of mouse skin and also result in an increase in the production of collagen I and III, and a decrease in the expression of MMP-1 and MMP-3. Compared with the UVB-irradiated group, we found that the irradiated fibroblasts additionally treated with baicalin demonstrated a decrease in the expression of SA-β-gal, a increase in the cell viability, a decrease in the G1 phase cell proportion, a downregulation in the level of senescence-associated and γ-H2AX proteins. However, Baicalin had no difference in the normal fibroblasts without UVB irradiation and long-term Baicalin incubation of UVB-SIPS fibroblasts gave no effects on the cell proliferation.
  
  
  CONCLUSIONS
  Taken together, these results suggest that baicalin significantly antagonizes photoaging induced by UVB in vivo and in vitro, indicating the potential of baicalin application for anti-photoaging treatment.
authors.affiliation: Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P. R. China.
authors.forename: Jia-an
authors.initials: JA
authors.lastname: Zhang
authors.affiliation: Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P. R. China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yin
authors.affiliation: Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P. R. China.
authors.forename: Li-wen
authors.initials: LW
authors.lastname: Ma
authors.affiliation: Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P. R. China.
authors.forename: Zhi-qiang
authors.initials: ZQ
authors.lastname: Yin
authors.affiliation: Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P. R. China.
authors.forename: Yan-yan
authors.initials: YY
authors.lastname: Hu
authors.affiliation: Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P. R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P. R. China.
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P. R. China.
authors.forename: Felicia
authors.initials: F
authors.lastname: Permatasari
authors.affiliation: Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P. R. China.
authors.forename: Dan
authors.initials: D
authors.lastname: Luo
authors.affiliation: Department of Dermatology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, P. R. China.
authors.forename: Bing-rong
authors.initials: BR
authors.lastname: Zhou
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016922:Cellular Senescence / Q000187:drug effects* / Q000502:physiology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005419:Flavonoids / Q000008:administration & dosage*; D006801:Humans; D051379:Mice; D008812:Mice, Hairless; D012867:Skin / Q000187:drug effects* / Q000528:radiation effects; D015595:Skin Aging / Q000187:drug effects* / Q000473:pathology; D014466:Ultraviolet Rays; D001616:beta-Galactosidase / Q000096:biosynthesis
chemical_list: D005419:Flavonoids; C038044:baicalin; D001616:beta-Galactosidase