title: Changes induced by ozone and ultraviolet light in type I collagen. Bovine Achilles tendon collagen versus rat tail tendon collagen.
abstract: High-molecular-mass aggregates were made soluble from insoluble collagens of bovine Achilles tendon and rat tail tendon by limited thermal hydrolysis. These polymeric collagen aggregates were cross-linked by 390-nm-fluorescent 3-hydroxy-pyridinium residues (excited at 325 nm) in the former tendon and by unknown non-fluorescent residues in the latter. With the solubilized insoluble-collagens from both tendons, as well as with acid-soluble collagen from rat tail tendon, other 350-385-nm fluorescence intensities (excited at 300 nm) were found to be higher in monomeric chains than in dimeric and polymeric chains. Low levels of ozone inhibited fibril formation of acid-soluble collagen particularly from young rat tail tendon, reacting with tyrosine residues and the 350-385-nm fluorophores. Aldehyde groups, involved in cross-linking, were not effectively modified by ozone. beta-Components (alpha-chain dimers) were not efficiently dissociated even by higher doses of ozone compared to gamma-components (alpha-chain trimers). Polymeric chain aggregates from bovine Achilles tendon collagen, whose 3-hydroxy-pyridinium cross-links are cleaved by ozone, were more readily dissociated by ozone than those from rat tail tendon collagen. Ultraviolet (300-nm) light, which destroyed the 350-385-nm fluorophores, inhibited fibril formation less effectively than ultraviolet (275-nm) light, which is absorbed by tyrosine residues, and did not dissociate collagen polymers from rat tail tendon. On the other hand, ultraviolet (320-nm) light, absorbed by 3-hydroxy-pyridinium cross-links which were rapidly photolyzed, partially dissociated polymeric collagen aggregates from bovine Achilles tendon after subsequent heating.
mesh_terms: D000125:Achilles Tendon / Q000187:drug effects / Q000528:radiation effects; D000143:Acids; D000818:Animals; D002417:Cattle; D002847:Chromatography, Agarose; D003094:Collagen / Q000528:radiation effects*; D004591:Electrophoresis, Polyacrylamide Gel; D006868:Hydrolysis; D010126:Ozone / Q000494:pharmacology*; D051381:Rats; D012995:Solubility; D013045:Species Specificity; D013050:Spectrometry, Fluorescence; D013623:Tail; D013710:Tendons / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D000143:Acids; D010126:Ozone; D003094:Collagen