Elevated mitochondrial respiration and superoxide production in diabetic PMN
Chahal, Terinder Kaur
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Oxidative stress is a major pathogenic mechanism leading to the complications of diabetes. Zymosan A-elicited PMN isolated from diabetic Akita mice release more superoxide compared to wild type (WT) PMN. Objectives: As mitochondrial superoxide production is increased in endothelial cells in diabetes, we hypothesized that mitochondria contribute to the elevated free radical production in PMN as well. Methods: Oxygen consumption by zymosan A-elicited murine peritoneal PMN was measured using a bioIogical oxygen monitor model 5300 equipped with a 5331 standard oxygen probe (YSI). Mitochondria were labeled with rhodanine 123 and mitochondrial superoxide production was determined with MitoSox Red staining followed by flow cytometry (FACScan). Results: Oxygen consumption is increased in Akita PMN (0.21 [plus or minus] 0.5 nmol O subscript 2/min*10 ^ cells) compared to WT (0.09[plus or minus]0.02 nmol O subscript 2/min*106 cells, P[less than] 0.05, n = 7). The number of mitochondria per PMN as determined with Rhodamine 123 staining and flow cytometry is similar in Akita and WT PMN (WT: 27.46 [plus or minus] 6 Akita: 23.07[plus or minus]3.85 arbitrary fluorescence units, P = 0.96).Mitochondrial superoxide production is elevated in Akita PMN by 23%, approaching statistical significance as determined with MitoSox Red staining followed by flow cytometry (WT: 39.28 [plus or minus] 1 1.58, Akita 48.44 [plus or minus] 10.98 arbitrary fluorescence units, n = 6, P = 0.055) Conclusion: Mitochondrial respiration is accelerated in diabetic Akita PMN. The relative number of mitochondria in PMN is not altered by chronic hyperglycemia. However,the accelerated respiratory rate results in increased superoxide production.Thus,leukocytes may contribute to micro vascular free radical damage not only with superoxide from NADPH oxidase, but also with superoxide of mitochondrial origin. Supported by NIH NIDCR R0I DE016933 and DE15566.
PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact firstname.lastname@example.org.Thesis (MSD) --Boston University, Henry M. Goldman School of Dental Medicine, 2010 (Department of Periodontology and Oral Biology).Includes bibliographic references: leaves 60-85.
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