title: Collagen pleomorphism in Descemet's membrane of streptozotocin-induced diabetic rats: an electron microscopy study.
abstract: BACKGROUND
  Diabetes mellitus causes ultrastructural changes in various basement membranes. These changes include increase in collagen biosynthesis rate and production of altered collagen.
  
  
  OBJECTIVE
  To evaluate the ultrastructural changes in the corneas of streptozotocin- induced diabetic rats, focusing on Descemet's membrane.
  
  
  METHODS
  Sprague-Dawley rats were sacrificed at different intervals after induction of diabetes mellitus by streptozotocin. Ten animals were sacrificed 1, 2, 3, 4, 6, 8, and 12 months after the injection of streptozotocin. Five untreated rats of the same age were used as normal controls and were sacrificed at the same intervals. Ultrathin sections were obtained from the corneas and were examined by transmission electron microscopy.
  
  
  RESULTS
  Unusual 120-nm-spaced collagen fibril bundles were found in Descemet's membrane of the diabetic rats as early as the second month following the induction of diabetes. Their concentration and size increased gradually over the follow-up period of 12 months.
  
  
  CONCLUSIONS
  Changes in the morphologic features of the collagen within Descemet's membrane may occur in diabetic-induced rats. The appearance of wide-spaced collagen fibrils in Decemet's membrane may represent alteration in collagen biosynthesis by the endothelial cells in diabetes or altered assembly of collagen due to increased glycosylation of normal formed collagen.
authors.affiliation: Department of Ophthalmology, Western Galilee--Nahariya Medical Center, Nahariya, Israel.
authors.forename: U
authors.initials: U
authors.lastname: Rehany
authors.forename: Y
authors.initials: Y
authors.lastname: Ishii
authors.forename: M
authors.initials: M
authors.lastname: Lahav
authors.forename: S
authors.initials: S
authors.lastname: Rumelt
mesh_terms: D000818:Animals; D048429:Cell Size; D003094:Collagen / Q000648:ultrastructure*; D003316:Corneal Diseases / Q000473:pathology*; D003886:Descemet Membrane / Q000648:ultrastructure*; D003921:Diabetes Mellitus, Experimental / Q000473:pathology*; D005260:Female; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003094:Collagen