The role of sex and genotype on antiorthostatic suspension effects on the mouse peripheral skeleton.

Previous antiorthostatic suspension studies have used a single sex and strain of rat or mouse. Nonetheless, broadly similar effects of suspension on the two species indicates a generalized effect of suspension not attributed to specific genetic, behavioral, or sex-linked etiology. In order to directly test genetic and sex-linked factors, the effects of suspension on the appendicular bone of male and female BALB-CJ, C57BL-6J, and DBA-2J mice were compared. These genotypes were selected based on their widely different developmental and behavioral characteristics as well as on past research involving a heterogeneous strain derived from these strains. The effects of suspension on the geometric, mechanical, and material properties of the femora, humeri, and tibiae were determined. Among the bone types, the femora were most significantly affected by suspension. The effects of suspension were similar in nature in male and female mice aged 1.7 months. Strain-dependent suspension effects may be indicative of bone developmental differences in the strains at the age chosen.