Effects of thermal injury on skeletal metabolism in two strains of mice.

Abstract

Long-term growth retardation occurs in children and osteopenias occur among children and adults who have been burned or suffer other injuries that result in a systemic inflammatory response. The purpose of this study was to define some of the growth, and to determine cancellous and cortical bone changes that occur following thermal injury in several contrasting strains of mice. Male C3H/HeN and Balb/c mice were given about a 20% total body thermal injury and 10 days later skeletal tissues were collected. The bone ash weights of the burned animals from both strains were less than their sham controls. In both strains, cancellous bone volumes were less in the burned animals than in their respective sham or baseline control groups. The loss of bone was particularly evident in the secondary spongiosa regions and also included a decrease in trabecular thickness and connectivity and an increase in trabecular separation. Longitudinal (endochondral) growth was suppressed in the burn animals. In the burned animals, indices of cancellous bone formation were substantially reduced whereas those in cortical bone were essentially nonexistent. The numbers of osteoclasts were increased in cancellous bone, and endocortical eroded surface was increased in the burn animals. These data show that there are rapid and profound changes in skeletal growth and metabolism in an experimental model of thermal injury. In general, a greater relative response was observed in the Balb/c vs. the C3H/HeN strain. Thermal injury resulted in a rapid and dramatic suppression of bone formation and endochondral growth with increased bone resorption in both cancellous and cortical bone.