Noninvasive assessment of alveolar microvascular recruitment in conscious non-sedated rats

Cuneyt Yilmaz, Dan M. Dane, Priya Ravikumar, Roger H Unger, Connie C Hsia

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Recruitment of alveolar microvascular reserves, assessed from the relationship between pulmonary diffusing capacity (DLCO) and perfusion (Q̇c), is critical to the maintenance of arterial blood oxygenation. Leptin-resistant ZDF fatty diabetic (fa/fa) rats exhibit restricted cardiopulmonary physiology under anesthesia. To assess alveolar microvascular function in conscious, non-sedated, non-instrumented, and minimally restrained animals, we adapted a rebreathing technique to study fa/fa and control non-diabetic (+/+) rats (4-5 and 7-11mo old) at rest and during mild spontaneous activity. Measurements included O2 uptake, lung volume, Q̇c, DLCO, membrane diffusing capacity (DMCO), capillary blood volume (Vc) and septal tissue-blood volume. In older fa/fa than +/+ animals, DLCO and DMCO at a given Q̇c were lower; Vc was reduced in proportion to Q̇c. Results demonstrate the consequences of alveolar microangiopathy in the metabolic syndrome: lung volume restriction, reduced Q̇c, and elevated membrane resistance to diffusion. At a given Q̇c, DLCO is lower in rats and guinea pigs than dogs or humans, consistent with limited alveolar microvascular reserves in small animals.

Original languageEnglish (US)
Pages (from-to)105-112
Number of pages8
JournalRespiratory Physiology and Neurobiology
Issue number1
StatePublished - Jan 1 2014


  • Alveolar microangiopathy
  • Lung diffusing capacity
  • Metabolic syndrome
  • Obesity
  • Pulmonary blood flow
  • Type-2 diabetes mellitus

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology
  • Pulmonary and Respiratory Medicine


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