title: Ultrastructural visualization of elastic fibres with a tannate--metal salt method.
abstract: A modification of the tannic acid-metal salt method was applied as an ultrastructural stain for elastin. Thin sections of glutaraldehyde-fixed, embedded rat aorta and rabbit elastic cartilage, with and without osmication, were examined. Raising the pH of the tannic acid solution from 2.7 to 9.0 progressively increased the electron-density of elastic fibres and collagen fibrils in osmicated and unosmicated specimens. The maximum tannic acid staining of elastic fibres was observed in the pH range 7.0-9.0. Collagen staining, although less intense than that of elastic fibres, was also greatest in this pH range. Elastic fibres in osmicated specimens demonstrated the strongest tannic acid staining with a minimal increase in density of collagen and cell nuclei when compared to the unosmicated specimens. Sequential treatments of osmicated specimens with tannic acid pH 7.0-9.0, and uranyl acetate, pH 4.1, enhanced the density of the elastin intensely, increased collagen staining moderately, but hardly increased the density of nuclei and microfibrils. In elastase-digested osmicated specimens, all tannic acid (pH 7.0)-uranyl acetate-reactive elastin was selectively removed. These results demonstrate that all the neutral and alkaline tannic acid-uranyl acetate methods can be used as a postembedment stain for elastin specimens fixed in glutaraldehyde and osmium tetroxide.
authors.forename: M
authors.initials: M
authors.lastname: Kageyama
authors.forename: M
authors.initials: M
authors.lastname: Takagi
authors.forename: R T
authors.initials: RT
authors.lastname: Parmley
authors.forename: M
authors.initials: M
authors.lastname: Toda
authors.forename: H
authors.initials: H
authors.lastname: Hirayama
authors.forename: Y
authors.initials: Y
authors.lastname: Toda
mesh_terms: D000818:Animals; D001011:Aorta / Q000648:ultrastructure; D004431:Ear, External / Q000648:ultrastructure; D004547:Elastic Tissue / Q000648:ultrastructure*; D004549:Elastin; D005404:Fixatives; D047348:Hydrolyzable Tannins; D009942:Organometallic Compounds; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D013194:Staining and Labeling; D013634:Tannins; D014501:Uranium
chemical_list: D005404:Fixatives; D047348:Hydrolyzable Tannins; D009942:Organometallic Compounds; D013634:Tannins; C005460:uranyl acetate; D014501:Uranium; D004549:Elastin