Resistive breathing activates the glutathione redox cycle and impairs performance of rat diaphragm

A. Anzueto, F. H. Andrade, L. C. Maxwell, S. M. Levine, R. A. Lawrence, W. J. Gibbons, S. G. Jenkinson

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


Free radical activation and lipid peroxidation have been described in skeletal muscle during strenuous exercise. We hypothesized that oxygen radicals could also be formed in the diaphragm muscle during strenuous resistive breathing and that these radicals might affect diaphragm function. Seven control and 12 experimental male Sprague-Dawley rats were studied. Six experimental animals were subjected to resistive breathing (RB) alone and six animals received 15 min of mechanical ventilatory support (MV) after the resistive breathing period. Inspiratory resistance was adjusted to maintain airway opening pressure at 70% maximum in both groups until exhaustion. Diaphragm samples were obtained for analysis of thiobarbituric acid-reactive substances (TBAR), reduced glutathione (GSH), and glutathione disulfide (GSSG). In vitro isometric contraction times, twitch (P(t)) tension and maximum tetanic (P(o)) tension, force-frequency curves, fatigue index, and recovery index were measured. In RB and MV compared with controls, there were significant decreases in P(t) and P(o). Diaphragm TBAR concentrations were increased in MV compared with controls or RB. GSSG-to-total glutathione ratio was increased in RB and MV compared with controls. Production of free radicals during RB and MV may represent an important mechanism of diaphragmatic injury that could contribute to the decline in contractility.

Original languageEnglish
Pages (from-to)529-534
Number of pages6
JournalJournal of Applied Physiology
Issue number2
StatePublished - 1992


  • antioxidant
  • contractile properties
  • free radicals
  • injury
  • lipid peroxidation
  • malondialdehyde
  • respiratory muscles
  • thiobarbituric acid- reactive substances

ASJC Scopus subject areas

  • General Medicine


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