Abstract: Objective To explore the effect of ultra-early hyperbaric oxygenation (HBO) on bone calcium, biomechanical properties and bone collagen of femur in rats with complete spinal cord transaction. Methods A total of 75 Sprague-Dawley rats were randomly divided into sham group (n=15), model group (n=20) and HBO group (n=40). HBO group was divided into three hours group (HBO1 group, n=20) and twelve hours group (HBO2 group, n=20). All groups underwent laminectomy at T10, while the model group, HBO1 group and HBO2 group underwent complete spinal cord transection at the same level. Three hours and twelve hours after surgery, HBO1 group and HBO2 group received HBO, respectively, for three courses with ten days in a course. After treatment, the femoral biomechanical properties, bone calcium and hydroxyproline (Hyp) were determined. The morphology of bone trabecula and the bone collagen was observed with HE staining and Masson triad color staining, respectively. Results After treatment, compared with the sham group, the femoral biomechanical properties, the content of bone calcium and Hyp decreased in the model group (P<0.05); compared with the model group and HBO2 group, they increased in HBO1 group (P<0.05). The number of bone trabecula and the bone collagen decreased, and derangement and sparseness were observed in the model group; however, the changes were substantially mild in HBO1 group. Conclusion Ultra-early HBO could increase the content of bone calcium and Hyp of femur, improve the morphology of the femur bone collagen, and improve the femoral biomechanical properties in rats with complete spinal cord transection.

Key words: complete spinal cord transection, hyperbaric oxygenation, ultra- early stage, femur, bone calcium, bone biomechanical properties, bone collagen, rats