Changes in bone metabolism in a rat model of traumatic brain injury

Primary objective: To evaluate the process of bone metabolism after traumatic brain injury. Research design: Randomized controlled trial. Methods and procedures: Rats were randomly assigned to either the brain injury group or to the sham-operation group using a fluid percussion device. The BMDs of lumbar vertebrae and proximal femur and bone turnover markers, osteocalcin and carboxy-terminal telopeptide, were measured at three points: the day before surgery and 1 and 3 weeks post-operatively. The biomechanics (maximum load of tibia and femoral neck) were measured 3 weeks post-operatively. Main outcomes and results: There was significant change in the BMDs of lumbar vertebrae 1 week post-operatively and of both distal femurs 3 weeks post-operatively (p < 0.05). A significant change in the maximum load of femoral neck was also observed 3 weeks post-operatively between the brain injury and the sham-operation groups (p = 0.044). Conclusions: This finding suggests that brain injury could induce osteoporosis by immobilization.