title: Therapeutic efficacy of trehalose eye drops for treatment of murine dry eye induced by an intelligently controlled environmental system.
abstract: OBJECTIVE
  To determine whether eye drop instillation of the disaccharide trehalose (TT) alleviates ocular surface damage in a dry eye murine model.
  
  
  METHODS
  Dry eye was induced in mice using an intelligently controlled environmental system (ICES). After 21 days housed in the ICES without topical treatment, the mice were randomly divided into three groups: no eye drops (ICES) for three weeks, four times a day with PBS 0.01 M 10 µl/eye bilaterally (ICES+PBS), or with TT 87.6 mM 10 µl/eye bilaterally (ICES+TT). Another mice group that was not exposed to the ICES and received no treatment served as a control group (UT). The ocular surface integrity, in each group, was evaluated using Oregon Green dextran (OGD) and fluorescein staining. The expression and distribution of occludin, involucrin, and small proline-rich protein 2 were determined with immunohistology analysis on whole mounted corneas. Heat shock protein 70 (HSP70) and matrix metalloproteinase 9 (MMP-9) expression was estimated with immunohistology. Ocular surface inflammation associated with each treatment was estimated with real time-PCR of interleukin-1β (IL-1β), IL-2, IL-6, IL-17, and tumor necrosis factor-alpha in the conjunctiva.
  
  
  RESULTS
  OGD staining in the cornea epithelium was lower in the ICES+TT group than in the ICES and ICES+PBS groups. Corneal epithelial occludin staining was markedly more homogenous in the ICES+TT group than in ICES and ICES+PBS groups, and there were no desquamating apical epithelial cells. Involucrin and small proline-rich protein 2 labeling of whole mounted corneas revealed upregulation of their expression in the groups, which received no treatment or PBS instillation compared to the ICES+TT group. HSP70 and MMP-9 immunolabeling revealed a marked increase in corneal epithelial expression in response to the ICES. The group treated with trehalose showed a similar profile expression of HSP70 and MMP-9 as the control group (UT). Conjunctival IL-1β, IL-2, IL-6, IL-17, tumor necrosis factor-alpha (TNF-α), and MMP-9 mRNA expression was lower in the ICES+TT group than in the ICES or ICES+PBS group.
  
  
  CONCLUSIONS
  Trehalose application restored ocular surface integrity, suppressed inflammatory and proteolytic MMP-9 and HSP70 expression, and keratinization in mice with dry eye damaged by a desiccative model.
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang, China.
authors.forename: Jinyang
authors.initials: J
authors.lastname: Li
authors.forename: Christophe
authors.initials: C
authors.lastname: Roubeix
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Shuai
authors.initials: S
authors.lastname: Shi
authors.forename: Guoting
authors.initials: G
authors.lastname: Liu
authors.forename: Christophe
authors.initials: C
authors.lastname: Baudouin
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
mesh_terms: D000818:Animals; D001483:Base Sequence; D003315:Cornea / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D055233:Cornified Envelope Proline-Rich Proteins / Q000378:metabolism; D016207:Cytokines / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004195:Disease Models, Animal; D015352:Dry Eye Syndromes / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D005260:Female; D020869:Gene Expression Profiling; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D062793:Occludin; D009883:Ophthalmic Solutions; D011498:Protein Precursors / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014199:Trehalose / Q000008:administration & dosage*
chemical_list: D055233:Cornified Envelope Proline-Rich Proteins; D016207:Cytokines; D017931:DNA Primers; D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; D062793:Occludin; C568986:Ocln protein, mouse; D009883:Ophthalmic Solutions; D011498:Protein Precursors; D012333:RNA, Messenger; C032253:involucrin; D014199:Trehalose; D020780:Matrix Metalloproteinase 9; C501830:Mmp9 protein, mouse