Purpose: Changes of bone metabolism begin from the initial stages of stroke; therefore, early prevention of these changes has become important. The most appropriate target for preventive therapy is to restrict the profound increase in osteoclastic bone resorption that occur soon after stroke. Oral bisphosphonates, which selectively target osteoclasts and their precursors, are appropriate drugs, but dysphagia or drowsiness after acute stroke can make it difficult to easily administer these compounds to stroke patients. The intravenous (IV) administration of bisphosphonates is an alternative method that can overcome these limitations. In order to determine the effect of IV bisphosphonates at the initial stages of stroke for preventing bone loss, an experiment using ischemic stroke rats was conducted.
Methods: Female Sprague-Dawley rats (n = 100) were randomly divided into four separate groups; sham surgery and vehicle-treated group (sham-vehicle), stroke and vehicle-treated group (stroke-vehicle), stroke with low-dose zoledronic acid treatment group (stroke-low) and stroke with high-dose zoledronic acid treatment group (stroke-high). Permanent occlusion of the left middle cerebral artery was performed, resulting in right hemiplegia. The bone mineral density (BMD) of the 4th and 5th lumbar vertebrae and the femur on the stroke side were measured in vivo on the day before stroke and on the 10th and 21st day after stroke. The osteocalcin and carboxy-terminal telopeptide blood levels were measured on the 10th and 21st day after stroke. The BMD of the excised proximal tibia and the maximum load of femoral neck were measured on the 21st day after stroke.
Results: After 21 days of stroke, the BMD of the lumbar vertebrae, femur, and excised tibia and the maximum load of the femoral neck in the sham-vehicle, stroke-low, and stroke-high groups were significantly higher than those in the stroke-vehicle group (P < 0.05). The carboxy-terminal telopeptide levels in the sham-vehicle and stroke-high groups were significantly lower than those in the stroke-vehicle group (P < 0.05).
Conclusion: The results suggest that IV zoledronic acid treatment might prevent bone loss during the initial stages of stroke.