Objective: To investigate the effects of simulated weightlessness and mechanical loading on bone interstitial fluid flow.
Method: Thirty-six male Sprague-Dawley [correction of Spargue-Danley] rats were divided into 3 groups: the control group, the tail-suspension group, and the tail-suspension plus mechanical loading group, with four rats in each group. All the rats were injected via a lateral tail vein with horseradish peroxidase on the 21st day of the experiment. Tibial tissue specimens were explanted, fixed, decalcified and cut into 30 micrometers frozen sections 3 h after the intravenous injection.
Result: There were less peroxidase reaction product in the bony matrix and bone lacunae in tail-suspended rats than the control and tail-suspended plus mechanical loading rats.
Conclusion: Tail-suspension decreased fluid movement through the bone, while mechanical loading increased it.