title: Age-related changes in antioxidant enzymes related to hydrogen peroxide metabolism in rat inner ear.
abstract: Oxidative stress is a pervasive factor in aging and has been implicated in noise-induced cochlear pathology. In this study, we measured the activities of two enzymes that catalyze the removal of hydrogen peroxide (H(2)O(2)), catalase and glutathione peroxidase (Gpx), in 3- and 24-month-old Fisher-344 rats, and reduced and oxidized glutathione in 3-, 12-, and 24-month-old rats. There was an increase in Gpx activity in vascular tissue (spiral ligament and stria vascularis), but no change in modiolar, sensory or vestibular tissue of the cochlea. The elevation in vascular tissue was age-related. We observed a significant elevation of catalase activity in vestibular tissue, a tendency for age-related elevation in the modiolus, but no change in vascular or sensory cochlear tissue. These findings suggest that increased Gpx activity in vascular cochlear tissue may be an age-related compensation for a decrease in glutathione and a decline in the redox state measured by the ratio of reduced to oxidized glutathione.
authors.affiliation: Center for Hearing and Deafness, University at Buffalo, UB South Campus, Buffalo, NY 14214, United States. dcoling@buffalo.edu
authors.forename: Donald
authors.initials: D
authors.lastname: Coling
authors.forename: Shan
authors.initials: S
authors.lastname: Chen
authors.forename: Lai-Har
authors.initials: LH
authors.lastname: Chi
authors.forename: Samson
authors.initials: S
authors.lastname: Jamesdaniel
authors.forename: Donald
authors.initials: D
authors.lastname: Henderson
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D002374:Catalase / Q000378:metabolism*; D003051:Cochlea / Q000033:anatomy & histology / Q000201:enzymology*; D019803:Glutathione Disulfide / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008297:Male; D010084:Oxidation-Reduction; D051381:Rats; D011916:Rats, Inbred F344; D055493:Spiral Ligament of Cochlea / Q000201:enzymology; D013316:Stria Vascularis / Q000201:enzymology
chemical_list: D006861:Hydrogen Peroxide; D002374:Catalase; D005979:Glutathione Peroxidase; D019803:Glutathione Disulfide
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