Abstract
The collagen types in the fetal and adult bovine corneal layers were compared. The cornea was separated into epithelial, endothelial, and stromal layers. Of the interstitial collagens, type I was the predominant in all layers of both fetal and adult corneas. Only type I of the interstitial collagens was found in the three layers of the adult cornea. Type I collagen was also found in all layers of the fetal cornea together with a minute amount, less than 2%, of type III collagen. The type III collagen could only be detected by cyanogen bromide peptide gel maps and was not apparent by gel electrophoresis of intact alpha chains. Of the noninterstitial collagens, type V was present throughout the three corneal layers. Type IV, basement membrane-specific collagen was found only in the endothelial and epithelial layers, which contain Descemet's and Bowman's membrane, respectively. The transient presence of type III collagen reflects an embryonic stage of corneal development.
Highlights
Into epithelial, endothelial,and stromal layers.Of the During embryonic development, collagen type synthesis is interstitial collagens, typIewas the predominant ianll modulated in a programmed sequence
Type I of the chick cornea, type I collagen is detected by immunofluothe interstitial collagens was founindthe three layers rescence studies in the corneal stromatastage 19
Type V was present throughout the three corneal layers.Type IV,basement membrane-specific collagen wasfound only in the endothelial and epithelial transiently in the corneal subepithelial layer [7].following invasion by fibroblasts, type I collagen becomes the predominant collagen within the stroma, while type 11 becomes progressively localized in subepithelial and subendothelial regions [9]
Summary
(Received for publication, September 1,1981, and in revised form, October 18,1981). From the Department of Pathology, University of California, Sun Francisco Medical Center, Sun Francisco, California ”. Solubilizationof Tissue-The three layers of adult and fetal corneas were extracted by limited pepsin quots were removed and designated as fraction 1 This was subjected digestion as described under"Materialsand Methods." Comto either lyophilization or dialysis and lyophilization. One of the correspond to acid-salt fraction 2 precipitated a t neutral pH at 1.7, methods to separate type 111 collagen from type I collagen by SDS- 2.6, and 4.5 M NaCI, respectively. Fractionation a t p H2.5 at a final NaCl concentration of 0.9 and 1.8 M preferentially separates interstitial collagens, types I, 11, and These two salt fractions were designated fractions 2 and 3, respectively. In fraction 3, inwhich the 1.8 M NaClfraction was obtained under acidic conditions, the two collagenous bands were precipitated only when salt was added toa finalconcentration of 4.5 M.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
