title: The effects of topical estriol and vehicle cream on the mechanical and histological properties of normal rat skin.
abstract: BACKGROUND
  The biomechanical and histological effects of topical estriol in normal rat skin are not clearly defined, although several favourable effects of estrogens have been suggested, especially in the postmenopausal period. Our goal was to determine whether estrogens have any such effects on skin histology and biomechanical properties in an experimental rat model.
  
  
  METHODS
  Estriol cream or vehicle cream was topically applied to the dorsum of Sprague Dawley rats of both genders in three separate groups for two weeks, and the results of the estriol and vehicle groups, as well as the non-treated control groups, were compared in terms of mechanical tensometric test results and histopathological evaluation.
  
  
  RESULTS
  After the application of topical estriol, histologically, subcutis thinned (p<0.01), the thickness of collagen fibrils increased (p<0.01), and elastic fibrils and dermal connective tissue cells appeared denser in female estriol group rats; mechanically, the elasticity modulus increased in the estriol groups of both sexes (p<0.05), whereas breaking strength, tensile strength and strain decreased in female estriol group rats (p<0.05).
  
  
  CONCLUSIONS
  Estrogens can change the mechanical and histological features of normal skin, and these changes are observed differently in female and male rats. Further studies to investigate the collagen structure and its interaction with ground substance, as well as effects of estriol on rat skin without a vehicle cream, are necessary to better understand the effects of estriol on skin mechanics.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Faculty of Medicine, Erciyes University, Kayseri, Turkey. ozyazgan@erciyes.edu.tr
authors.forename: Irfan
authors.initials: I
authors.lastname: Ozyazgan
authors.forename: Narin
authors.initials: N
authors.lastname: Liman
authors.forename: Teoman
authors.initials: T
authors.lastname: Eskitaşçioğlu
mesh_terms: D000818:Animals; D004548:Elasticity; D004964:Estriol / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D024022:Fibrillar Collagens / Q000187:drug effects; D008297:Male; D009824:Ointments; D014677:Pharmaceutical Vehicles; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000166:cytology / Q000187:drug effects*
chemical_list: D024022:Fibrillar Collagens; D009824:Ointments; D014677:Pharmaceutical Vehicles; D004964:Estriol