title: Reversal of ultraviolet B-induced immunosuppression by inhibition of the extracellular signal-regulated mitogen-activated protein kinase.
abstract: OBJECTIVE
  Topical treatment of the specific inhibitor PD98059 (PD) for extracellular signal-regulated kinase (ERK)1/2 combined with ultraviolet B (UVB) exposure in an in vivo study was proposed to confirm the effectiveness of ERK1/2 involved in UVB-induced immunosuppression that was reversed by PD.
  
  
  METHODS
  Based on the mouse model of local UVB-induced immunosuppression [UVB exposure, followed by sensitization with dinitrofluorobenzene (DNFB) on the abdomen skin before challenge on the ear site], the PD was applied on the abdomen-irradiated area 1 h, immediately before and 6 h after UVB exposure, respectively. The baseline of ear thickness was measured and remeasured 24 h after the challenge of DNFB for evaluation of ear-swelling response. Histopathologically, the ear biopsies were taken for hematoxylin and eosin staining.
  
  
  RESULTS
  Mice that received PD post-irradiation treatment showed a statistically significant contact hypersensitivity compared with the UVB-irradiated mice (P<0.05), and paralleled with the biopsy showing a thickened epidermis with lymphocyte infiltration. Thus, the PD had abrogated the UV-induced local suppression of contact hypersensitivity.
  
  
  CONCLUSIONS
  The ERK1/2 mitogen-activated protein kinase (MAPK) pathway plays an important role in the local UVB-induced immunosuppression, and its specific inhibitor PD can arrest its function, resulting in protection against UVB-induced immunosuppression in the present in vivo study.
authors.affiliation: Department of Dermatology, Hua-Shan Hospital, Fudan University, Shanghai, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Leng
authors.forename: Xiaoqun
authors.initials: X
authors.lastname: Luo
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.forename: Kefei
authors.initials: K
authors.lastname: Kang
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Zheng
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004139:Dinitrofluorobenzene / Q000008:administration & dosage; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors*; D005260:Female; D007108:Immune Tolerance / Q000528:radiation effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D047428:Protein Kinase Inhibitors; D004139:Dinitrofluorobenzene; D048049:Extracellular Signal-Regulated MAP Kinases