Effects of altitude acclimatization and deacclimatization on bone and marrow volume in dog

Abstract

Skeletons of altitude-acclimatized, altitude-deacclimatized, and sea-level control dogs were completely analyzed for water, fat, and nonfatty organic and inorganic fractions. The total skeletal and marrow volumes as well as their contents were calculated and compared. Neither the marrow volume nor the bone (trabecular and cortical) volume was affected by the altitude changes. The relative distribution of marrow and bone in the various parts of the skeleton was also unchanged. Marrow fat in the whole skeleton as well as in the individual parts of the skeleton was lowered on acclimatization and increased on deacclimatization. Of the fat lost, one-third was from the flat bones while one-half of the fat deposited on deacclimatization occurred in flat bones. The marrow water as well as the functional marrow (fat-free, by definition) in either the whole or the various parts of the skeleton was increased on acclimatization and decreased on deacclimatization.