Effects of change in environmental temperature and natural shifts in carbon dioxide and oxygen concentrations on the lungs of captive naked mole-rats (Heterocephalus glaber): A morphological and morphometric study

J. N. Maina, Y. Gebreegziabher, R. Woodley, R. Buffenstein

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

The lungs of the naked mole-rat Heterocephalus glaber were morphologically (qualitatively) and morphometrically (quantitatively) investigated in adult captive in-burrow body-temperature-maintained (CBTMA) and captive cold-exposed animals (CCEA). The observations were compared with those of field (burrow-dwelling) animals (FA) examined in an earlier study. The lungs of the captive animals were morphologically (qualitatively) similar to those of the field mole-rats. Conspicuous paedomorphic features, i.e. a preponderant double pulmonary capillary arrangement, incomplete differentiation of alveolar pneumocytes, and extension of a cuboidal epithelium to the immediate vicinity of the alveoli, were observed. The prevalent pulmonary underdevelopment was attributed to the relatively low metabolic rate of the poikilothermic naked mole-rat, a species that has evolved in a thermally stable environment. Measurable differences and similarities were found between the lungs of the captive naked mole-rats themselves (i.e. the CBTMA and the CCEA) and between the captive and the field ones. Genetic factors may help explain the conserved pulmonary structural features while environmental (gaseous) change from a hypoxic-hypercapneic (an oxygen deficient-high carbon dioxide concentration) to a normoxic-normocapnic atmosphere and the thermal shift respectively may have enforced pulmonary transformations between the CBTMA and the FA and between the CCEA and the CBTMA. Paradoxically, the CCEA had a significantly lower mass-specific total morphometric pulmonary diffusing capacity of 0.024 compared with that of 0.102 mlO2.s-1.mbar-1.kg-1 in the CBTMA. The observed morphometric differences indicate that the lung of the naked mole-rat, though morphologically unchanged, is intrinsically tractable to environmental shifts in its habitat. Studies on captive naked mole-rats should not be indiscriminately taken to be representative of the species.

Original languageEnglish (US)
Pages (from-to)371-382
Number of pages12
JournalJournal of Zoology
Volume253
Issue number3
DOIs
StatePublished - Mar 31 2001

Keywords

  • Diffusing capacity
  • Fossorial
  • Heterocephalus glaber
  • Hypercapnia
  • Hypoxia
  • Lung
  • Morphometry
  • Naked mole-rat

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology

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