Bone regeneration and maturation in a rabbit tibia lengthening model under low-intensity purse ultrasound stimulation / 中国组织工程研究

ABSTRACT

BACKGROUND: Experiments has demonstrated that low-intensity pulse ultrasound stimulations(LIPUS) can accelerate bone healing. However, Its affect mechanisms on maturation of regenerated bone remain unclear.OBJECTIVE: The hypothesis that LIPUS has positive effect on maturation of regenerate bone was put forward creatively, and wants to vedfy the hypothesis by compare the difference between LIPUS intervention and no intervention.METHODS: Thlrty-six adult, healthy, New Zealand White rabbits were randomly assigned to LIPUS treatment group and control.group, with 18 animals in each group.All animals were undergone mid-diaphyeaal tibia ostactomy and were immobilized in Orthofix M103 Mini lengtheners. After a eaven-day latency period, gradual distraction of 0.5 mm per twelve hours for 10 days to produce 10 mm distraction. A 4-weeks course of LIPUS treatment was applled over the distraction site for twenty minutes daily starting immediately after the completion of distraction. At weeks 4, 8, 12 after distraction, the bone healing was evaluated by X-ray film, and total mineralized areas were measured by Image J software. The newly formed bone In the lerigthening field was harvested and stained with haematoxylin-eosin, Masson's tdchroma end VG. Thearaas of newly formed bone were measured to calculate a percentage of the total callus area.RESULTS AND CONCLUSION: Thirty-six rabbits ware included in the final analysis, At week 4 after distraction, the maturation of newly formed bone in LIPUS treatment group appeared eadier than that in the control groups. The bona callus image presented in the marginal and center region of experimental defect, increased greatly and had higher density until filled of the lengthening fields. Many bone-like masses appeared in the newly formed tissues and the tissues surrounding the bone granules partially changed Into bone-like tissues, and the rate of callus production was increased (P ＜ 0.05). There was no significant difference between two groups at weeks 8 and 12 after distraction. Histological results showed that that new bone formation of the LIPUS group was earlier than the control group at weeks 4, 8, and 12 after distraction. The percentage of new bona on total callus area of the LIPUS group was greater than that of the control group at weak 4, but there was no obvious difference at weeks 8 and 12 after distraction. LIPUS accelerates new bone formation, increases the size of the distraction callus, exhibits highly effective in achieving maturation of bone in the animal modal with distraction osteogenesis.