Controlled Intramedullary Pressure Fluctuations Enhanced Periosteal and Endosteal Bone Formation in Young, but Not
Najmeh Sadat Hosseini1, Amanda Salas Sanchez1, Teresa Le1
1Department of Kinesiology, The University of Texas at Arlington, Arlington, TX 76019, USA.
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Mimicking vascular function in bone may serve to stimulate osteogenesis. We developed a micropump and wireless pressure sensing system to fluctuate and record intramedullary pressure (IMP) in the femoral diaphysis of young (6 months) and old (24 months) male Fischer-344 rats. In vivo IMP was determined (n = 5 per group). Additionally, two bone defects were created in the right femora (EXP) of young (n = 14) and old (n = 11) rats and catheterized to the micropump and wireless pressure sensor. Intramedullary pressure was fluctuated for 10 min. The left femur served as the control (CTL). Seven days post-surgery, femora were scanned by μCT (15 µm) to assess trabecular bone microarchitecture, cortical thickness and new bone volume at the endosteal and periosteal surfaces. Data were analyzed with SPSS software, and significance was p ≤ 0.05. In vivo IMP was lower (p < 0.05) in the old (~16 mmHg) vs. young (~36 mmHg) rats. Trabecular thickness in the proximal metaphysis was higher (p < 0.05) in the old rats, and the cortical shell was thicker (p < 0.05) and new bone volume greater (p < 0.05) in the young rats. Importantly, new bone volume was greater (p < 0.05) in young EXP (14 ± 7 mm3) vs. young CTL (7 ± 7 mm3) femora. A 10-min bout of IMP fluctuation stimulated osteogenesis in young rats.
