Technical note: development of a model for study of in vivo bone strains in normal and microgravity environments

A reproductible long-term strain gage bonding technique using hydroxyapatite (HA) to bond strain gages to the femora of rats is developed and is used to monitor strain changes caused by exposure to microgravity and simulated microgravity environments in relation to observed bone modeling. Four formulations of HA are tested for in vivo strain gage bonding in the rat model following either a 6- or 12-week period in vivo. Histomorphometry and backscatter electron microscopy are used to examine the effect of the different formulations of HA on periosteal bone formation and the extent to which bone bonding is achieved.