Effects of disrupted 1-integrin function on the skeletal response to short-term hindlimb unloading in mice

on the skeletal response to short-term hindlimb unloading in mice. J Appl Physiol 98: 690–696, 2005. First published October 1, 2004; doi:10.1152/japplphysiol.00689.2004.—The study was designed to determine whether 1-integrin plays a role in mediating the acute skeletal response to mechanical unloading. Transgenic (TG) mice were generated to express a dominant negative form of 1-integrin under the control of the osteocalcin promoter, which targets expres-sion of the transgene to mature osteoblasts. At 63 days of age, wild-type (WT) and TG mice were subjected to hindlimb unloading by tail suspension for 1 wk. Pair-fed, normally loaded WT and TG mice served as age-matched controls. Bone samples from each mouse were processed for quantitative bone histomorphometry and biome-chanical testing. The skeletal phenotype of TG mice was characterized by lower cancellous bone mass in the distal femoral metaphysis (52%) and lumbar vertebral body (20%), reduced curvature of th