Effects of Low-Intensity Pulsed Ultrasound on New Trabecular Bone during Bone–Tendon Junction Healing in a Rabbit Model: A Synchrotron Radiation Micro-CT Study

Abstract

This study was designed to evaluate the effects of low-intensity pulsed ultrasound on bone regeneration during the bone–tendon junction healing process and to explore the application of synchrotron radiation micro computed tomography in three dimensional visualization of the bone–tendon junction to evaluate the microarchitecture of new trabecular bone. Twenty four mature New Zealand rabbits underwent partial patellectomy to establish a bone–tendon junction injury model at the patella–patellar tendon complex. Animals were then divided into low-intensity pulsed ultrasound treatment (20 min/day, 7 times/week) and placebo control groups, and were euthanized at week 8 and 16 postoperatively (n = 6 for each group and time point). The patella–patellar tendon specimens were harvested for radiographic, histological and synchrotron radiation micro computed tomography detection. The area of the newly formed bone in the ultrasound group was significantly greater than that of control group at postoperative week 8 and 16. The high resolution three dimensional visualization images of the bone–tendon junction were acquired by synchrotron radiation micro computed tomography. Low-intensity pulsed ultrasound treatment promoted dense and irregular woven bone formation at week 8 with greater bone volume fraction, number and thickness of new trabecular bone but with lower separation. At week 16, ultrasound group specimens contained mature lamellar bone with higher bone volume fraction and thicker trabeculae than that of control group; however, there was no significant difference in separation and number of the new trabecular bone. This study confirms that low-intensity pulsed ultrasound treatment is able to promot bone formation and remodeling of new trabecular bone during the bone–tendon junction healing process in a rabbit model, and the synchrotron radiation micro computed tomography could be applied for three dimensional visualization to quantitatively evaluate the microarchitecture of new bone in bone–tendon junction.

In vitro effect of caveolin‐1 as a slow‐release material on bone‐tendon junction healing: A comparative study

“…After supplementation of the male animal model, histological findings at the incision showed no significant differences between females and males. This result is consistent with previous studies of traumatic femoral head necrosis animal models …”

“…This result is consistent with previous studies of traumatic femoral head necrosis animal models. 3,20,21 In addition, the cross-sectional area, breaking load and ultimate tensile strength of the healing interface were remarkably increased in the experimental group, indicating that caveolin-1 could play an important role in increasing the mechanical properties. It is in conformity with another research finding that mice injected caveolin-1 present enhanced lung mechanics with an obviously increased airway resistance.…”

“…The bone‐tendon junction is where the tendon attaches to the bone, and it is composed of soft tendon tissues and hard ones . Unfortunately, the injury of the bone‐tendon junction is increased and commonly found in trauma and sports exercise, caused by muscle loading, which often occurs in different ligaments, including Achilles tendon, anterior cruciate ligament, rotator cuff and patellar tendon . Hence, the research on bone‐tendon junction healing is of clinical value for preventing injuries and improving treatment .…”

“…1,2 Unfortunately, the injury of the bone-tendon junction is increased and commonly found in trauma and sports exercise, caused by muscle loading, which often occurs in different ligaments, including Achilles tendon, anterior cruciate ligament, rotator cuff and patellar tendon. 3 Hence, the research on bone-tendon junction healing is of clinical value for preventing injuries and improving treatment. 4 Nevertheless, bone-tendon junction healing is at a slower rate compared with bone-bone healing and tendon-tendon healing.…”

Dual growth factor‐immobilized asymmetrically porous membrane for bone‐to‐tendon interface regeneration on rat patellar tendon avulsion model

“…This also contributes to the high recurrence (rerupture) rates after surgical treatment of up to 94% (in rotator cuff tendon) . In recent years, tissue engineering strategies including the use of porous 3D matrices based on synthetic/natural polymers (e.g., poly( l ‐lactic acid) [PLLA], poly(glycolic acid) [PGA], poly( d , l ‐lactic‐ co ‐glycolic acid) [PLGA], polytetrafluoroethylene, poly(urethane urea), chitin, chitosan‐hyaluronan, and chondroitin sulfate‐hyaluronate acid‐silk fibroin) and extracellular matrices (ECMs; e.g., small intestine submucosa [SIS], dermis, and pericardium]); cells (e.g., mesenchymal stem cells [MSCs], muscle‐derived cells [MDCs], autologous bone marrow mononuclear cells [BMMCs], connective tissue progenitor cells [CTPs], and autologous tenocytes); and biological/physical stimuli (e.g., growth factors, genes, platelet‐rich plasma [PRP], ultrasound, shock wave, and cyclic tensile strain) have been considered as additional therapies to compensate for the inherent limitations of surgical treatment. Growth factors which play a pivotal role in biological processes (i.e., cellular proliferation, migration, adhesion, differentiation; and ECM deposition) to maintain and repair human body have been more frequently used in the reconstruction of musculoskeletal tissues.…”