title: Mouse model of dermal fibrosis induced by one-time injection of bleomycin-poly(L-lactic acid) microspheres.
abstract: OBJECTIVE
  Animal models are useful tools to study various aspects of human diseases. Bleomycin (BLM)-induced scleroderma mouse has been widely investigated as an animal model of scleroderma. Repeated injections of BLM, either daily or every other day, for 3-4 weeks are required to induce scleroderma in mice. Poly(L-lactic acid) (PLA) is a biodegradable, biocompatible and bioabsorbable device that has been widely investigated for controlled drug release. In this study, we fabricated BLM-containing PLA microspheres and subcutaneously injected them into C3H mice for only one time.
  
  
  METHODS
  Treated skins were harvested at days 7 and 21. Then, histological examination and collagen content measurement assay were performed. The mRNA expression of alpha1(I) collagen (COL1A1), monocyte chemoattractant protein-1 (MCP-1), TGF-beta(1) and connective tissue growth factor (CTGF) were quantified by real-time PCR.
  
  
  RESULTS
  Dermal fibrosis was histologically observed at day 7 after injection and remained present at day 21. Tissue responses against BLM-PLA microspheres alone were mild. Soluble collagen content and expression level of alpha1(I) collagen mRNA were significantly elevated at day 21. Expression levels of MCP-1 mRNA and TGF-beta(1) mRNA at day 7 and CTGF mRNA at day 21 were also elevated.
  
  
  CONCLUSIONS
  The present study demonstrated for the first time that one-time injection of BLM-PLA microspheres can induce dermal fibrosis in C3H mice. BLM-PLA microspheres thus offer a labour-saving, simple and powerful tool to establish an animal model of BLM-induced dermal fibrosis.
authors.affiliation: Department of Dermatology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan. yshibusa@showa.gunma-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Shibusawa
authors.forename: I
authors.initials: I
authors.lastname: Negishi
authors.forename: Y
authors.initials: Y
authors.lastname: Tabata
authors.forename: O
authors.initials: O
authors.lastname: Ishikawa
mesh_terms: D000818:Animals; D001761:Bleomycin / Q000008:administration & dosage* / Q000633:toxicity; D018932:Chemokine CCL2 / Q000096:biosynthesis / Q000235:genetics; D003094:Collagen / Q000032:analysis; D024042:Collagen Type I / Q000096:biosynthesis / Q000235:genetics; D000090602:Collagen Type I, alpha 1 Chain; D055513:Connective Tissue Growth Factor; D003692:Delayed-Action Preparations; D004195:Disease Models, Animal; D005260:Female; D005355:Fibrosis / Q000139:chemically induced / Q000378:metabolism; D015870:Gene Expression; D017874:Immediate-Early Proteins / Q000096:biosynthesis / Q000235:genetics; D007279:Injections, Subcutaneous; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis / Q000235:genetics; D019344:Lactic Acid; D051379:Mice; D008809:Mice, Inbred C3H; D008863:Microspheres; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics; D012595:Scleroderma, Systemic / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D012867:Skin / Q000378:metabolism / Q000473:pathology*; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000235:genetics
chemical_list: C526317:CCN2 protein, human; C526318:CCN2 protein, mouse; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D003692:Delayed-Action Preparations; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D001761:Bleomycin; D055513:Connective Tissue Growth Factor; D019344:Lactic Acid; D003094:Collagen