title: Low-intensity pulsed ultrasound accelerated bone-tendon junction healing through regulation of vascular endothelial growth factor expression and cartilage formation.
abstract: The purpose of this study was to use our established partial patellectomy rabbit model to study the effects of low-intensity pulsed ultrasound (LIPUS) on patella-patellar tendon (PPT) junction repair through hypothesized pathways including regulation of vascular endothelial growth factor (VEGF) and chondrogenesis. Standard partial patellectomy was conducted in sixty-four 18 wk-old rabbits that were subsequently divided into LIPUS and control group. The PPT complex was harvested at week 2, 4, 8 and 16 postoperatively (n = 8 for each time point) for preparation of sagittal sections that were evaluated for angiogenesis by analyzing VEGF expression and chondrogenesis. Results showed differences in the pattern of VEGF expression between LIPUS and control groups during the entire healing process, i.e., significant differences in the average percentage of VEGF expression found in between the LIPUS and the control groups. At postoperative week 4, the chondrocytes and osteoblasts in woven bone expressed significantly more VEGF in the LIPUS group than that in the control group (35.6% +/- 7.0% versus 28.0% +/- 4.6%, p < 0.05). Compared with the control group, the development of cartilaginous metaplasia was found more advanced in the scar tissue next to the articular cartilage of the remaining patella in the LIPUS group that was expressed with VEGF in the chondrocytes (38.8% +/- 12.3%). However, the specimens in the control group just showed the similar cartilaginous metaplasia region until postoperative week 8. Histomorphometry revealed thicker fibrocartilage zone and larger cartilaginous metaplasia field at PPT healing interface in LIPUS group compared with those of the control group at week 8 and 16. In conclusion, this was the first quantitative study to demonstrate that LIPUS improved B-T junction healing through regulation of VEGF expression in early healing phase and subsequent chondrogenesis.
authors: Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Hong Kong SAR, PR China.
authors: Hongbin
authors: H
authors: Lu
authors: Ling
authors: L
authors: Qin
authors: Winghoi
authors: W
authors: Cheung
authors: Kwongman
authors: K
authors: Lee
authors: Wannar
authors: W
authors: Wong
authors: Kwoksui
authors: K
authors: Leung
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D050376:Bone-Patellar Tendon-Bone Grafting; D020219:Chondrogenesis / Q000502:physiology; D005260:Female; D017102:Fracture Healing; D007150:Immunohistochemistry; D023421:Models, Animal; D010027:Osteotomy; D010329:Patella / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D017847:Patellar Ligament / Q000473:pathology / Q000637:transplantation; D011509:Proteoglycans / Q000032:analysis; D011817:Rabbits; D011897:Random Allocation; D013708:Tendon Injuries / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D016896:Treatment Outcome; D014464:Ultrasonic Therapy / Q000379:methods*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis / Q000378:metabolism*; D014945:Wound Healing
chemical_list: D015415:Biomarkers; D011509:Proteoglycans; D042461:Vascular Endothelial Growth Factor A