Does low-intensity pulsed ultrasound accelerate phasic calcium phosphate ceramic-induced bone formation?

Purpose: Low-intensity pulsed ultrasound (LIPUS) has been used to stimulate the healing of the fresh fracture, delayed union, and non-union in both animal and clinical studies. Besides, biphasic calcium phosphate ceramic (BCP) is a promising biomaterial for bone repair as it shows favorable biocompatibility, osteoinduction, and osteoconduction. However, scarcity is known about the combined effect of LIPUS and BCP on bone formation. Methods: The combined effect of LIPUS and BCP was studied in a beagle model. Twelve dogs were used. BCP granules without any additions were implanted into bilateral erector spinae muscles. One side is the BCP group, while the counterlateral side is LIPUS + BCP group. Histological and histomorphometric analyses, and quantitative real-time polymerase chain reaction were evaluated. Results: Compared with BCP alone, the LIPUS + BCP showed no advantages in early bone formation. Furthermore, the Notch signaling pathway-related mRNA has no significant difference between the two groups. Conclusions: The preliminary results showed that the BCP, which has intrinsic osteoinduction nature, was an effective and promising material. However, LIPUS has no enhanced effect in BCP induced ectopic bone formation. Furthermore, LIPUS has no effect on the Notch signaling pathway. Whether costly LIPUS could be used in combination with BCP should be a rethink.

Contribuição da aplicação do ultrassom de baixa potência na prevenção de osteopenia em tíbias de ratos sob ausência de carga / The contribution of the application of low power ultrasound to the prevention of rat tibial osteopenia under the absence of load

Este trabalho objetivou verificar se o ultrassom de baixa potência (US) previne a ocorrência de osteopenia em tíbias de ratos sob ausência de carga. Foram utilizados 45 Rattus novergicus albinus, Wistar adultos, machos, distribuídos em cinco grupos iguais: C - animais-controle livres em gaiolas por 21 dias; S - animais suspensos pela cauda por 21 dias; ST - suspensos pela cauda por 21 dias e concomitantemente tratados com US; S→C - suspensos por 21 dias e depois permanecendo livres em gaiolas por mais 21 dias; S→CT - suspensos por 21 dias e depois permanecendo livres em gaiolas por mais 21 dias e concomitantemente tratados com US. O tratamento foi realizado com US de 1,5MHz, ciclo de trabalho 1:4, 30mW/cm², na tíbia direita, por 15 sessões de 20 minutos cada, cinco sessões por semana. Ainda vivos, os animais foram submetidos a exame de densitometria óssea para verificação da densidade mineral óssea (DMO) e do conteúdo mineral ósseo (CMO). Após a eutanásia dos animais, as tíbias foram desarticuladas, dissecadas e submetidas a ensaio mecânico destrutivo para análise da força máxima (Fmáx) e da rigidez (R). Foram avaliados também o comprimento (L) e o diâmetro (D) no ponto médio da tíbia. O grupo S apresentou valores de DMO, CMO, Fmáx, R, L e D menores em relação ao grupo C, demonstrando que a suspensão pela cauda é prejudicial a estas variáveis. O tratamento dos animais suspensos com o US, grupo ST, elevou os valores de CMO e DMO em relação aos do grupo S, igualando-os aos do grupo C...

This work intended to verify if the low power ultrasound (US) prevents the occurrence of osteopenia on the tibia of rats under the absence of load. 45 adult male Wistar Rattus novergicus albinus were used, separated in five equal groups: C - control free animals in cages for 21 days; S - animals suspended by the tail for 21 days; ST - animals suspended by the tail for 21 days and concurrently treated with US; S→C - animals suspended for 21 days and then free in cages for another 21 days; S→CT - animals suspended for 21 days and then free in cages for another 21 days and concurrently treated with US. The treatment was performed with US with 1.5 MHz, work cycle 1:4, 30 mW/cm², on tibia, for 15 sessions of 20 minutes each, 5 sessions per week. While still alive, the animals underwent bone densitometry examination to verify the Bone Mineral Density (BMD) and the Bone Mineral Content (BMC). After the euthanasia of the animals, the tibias were disjointed, dissected and underwent destructive mechanical testing for the analysis of the maximum force (Fmax) and Rigidity (R). The length (L) and the diameter (D) of the middle point of the tibia were also measured. In group S, BMD, BMC, Fmax, R, L and D were smaller than in group C, demonstrating that the suspension by the tail is detrimental to these variables. The treatment of the suspended animals with the US, in group ST, increased the BMD and BMC compared to group S, leveling them to group C...

Evaluation of rats´ soleus muscle submitted to remobilization protocol with therapeutic ultrasound associated with static stretching

Despite the deleterious effects, immobilization, is still often used in the treatment of musculoskeletal disorders, even with the occurrence of muscular atrophy, its reversal is a major challenge to rehabilitation. The aim of this study was evaluate the tropism of rats soleus muscle submitted to remobilization with static stretching, preceded by ultrasound, thermal and non thermal. We used 28 rats divided into four groups: G1‑immobilized and remobilized with static stretching, G2-remobilized with stretching preceded by ultrasound 1.0 W.cm–²; G3 – ultrasound at 0.5 W.cm–² , G4 – ultrasound with 0.2 W.cm–². All animals were immobilized in plantarflexion, producing shortening of the right soleus muscle for 15 days. For the groups subjected to remobilization with ultrasound doses were used according to the group, for 3 minutes, for 10 days with an interval of 2 days after the 5th treatment. After treatment with ultrasound (or not for the G1), the animals were subjected to 3 sets of 30 seconds, with 30 seconds interval between them, of static stretching of the soleus. The soleus were dissected, weighed and processed for preparation of histological slides in cross section, and evaluated the smallest diameter of 100 fibers per muscle. There was significant reduction in weight between left and right muscles in all groups, for diameters G3 showed no difference. Conclusion: stretching with or without ultrasound, was unable to reverse the deleterious effects of immobilization on muscle weight, but in the mean dose there was protective effect on the diameter of the fibers.

Tratamiento con ultrasonido continuo de alta intensidad en nervios isquiáticos de rata (Sprague Dawley) lesionados por compresión / Treatment with continuous high-intensity ultrasound on rat sciatic nerve (Sprague Dawley) and compression injuries

Actualmente las patologías compresivas de nervios espinales son de alta incidencia. Como una forma de contribuir con fundamentos morfológicos a la aplicación de ultrasonido terapéutico se realizó la presente experiencia, que se refiere a la reparación de los nervios espinales luego de una injuria compresiva. Para esto se utilizaron 9 ratas Sprague Dawley las cuales fueron separadas en tres grupos con 3 ratas cada uno: A) control sano, B) control lesionado y C) aplicación de ultrasonido terapéutico de 1w/cm2. Las ratas de los grupos B y C fueron anestesiadas y se les aisló quirúrgicamente el nervio isquiático, el cual fue pinzado durante 45 segundos con una fuerza constante de 40N. La compresión se realizó a 10mm sobre su bifurcación distal, luego se desinfectó y suturó. 24 horas después de la compresión las ratas del grupo C fueron irradiadas con un equipo de ultrasonido terapéutico, utilizando 1w/cm2 de intensidad con frecuencia de 3 MHZ y un cabezal de 0,5cm2, durante 1 minuto y en 10 días seguidos. 28 días después de la irradiación se extrajeron los nervios isquiáticos y fueron sometidos a técnicas histológicas de rutina con tinción de HE y VG. Se realizó el diagnóstico histopatológico y la morfometría donde se midió: grosor del perineuro, perímetro de los núcleos de neurilemocitos, perímetro del axón mielínico, perímetro de la mielina, ancho del núcleo del fibroblastocito y largo del núcleo del fibroblastocito. Los resultados permiten concluir que el ultrasonido de modalidad continua estimula la regeneración del nervio espinal lesionado por compresión.

Currently, the pathologies of spinal nerves are of high incidence. As a way to contribute to morphological grounds the application of therapeutic ultrasound was used in the repair of spinal nerves after a compressive injury. 9 tests were carried out using Sprague Dawley rats which were separated into three groups with 3 rats each: A) healthy control, B) injured control and C) the application of therapeutic ultrasound 1w/cm2. The rats in groups B and C were anesthetized and sciatic nerve was surgically isolated, which was clamped for 45 seconds with constant force of 40N. Compression was performed on the distal bifurcation 10mm, then disinfected and sutured. 24 hrs after compression, rats in group C were irradiated with a therapeutic ultrasound equipment, using 1w/cm2 of intensity with frequency of 3 MHz and a head of 0.5 cm2 for 1 minute, for 10 days. 28 days after irradiation sciatic nerve was removed and subjected to routine histological staining with HE and VG. Histopathological diagnosis was made and morphometry which measured: perineum thickness, perimeter of the nuclei of neurolemocyte cell, perimeter of myelinated axons, perimeter of myelin, the fibroblastocyte core width and length of the fibroblastocyte nucleus. The results show that the continuous mode ultrasound stimulates the regeneration of injured spinal nerve compression.

O ultra-som terapêutico de 1 MHz, na dose de 0,5 W cm-2, sobre o tecido ósseo de cães avaliado por densitometria óptica em imagens radiográficas / The 1 MHz therapeutic ultrasound, in doses of 0.5W cm-2, on dog's bone tissue evaluated through optic densitometry in radiographic images

As lesões tendíneas nas extremidades distais dos membros estão entre as mais freqüentes alterações do aparelho locomotor na rotina clínico-cirúrgica humana e animal e, não raro, necessitam de terapias adjuvantes para seu completo retorno às funções fisiológicas. O ultra-som terapêutico (UST) é a modalidade mais utilizada nas clínicas de reabilitação para tratar lesões tendíneas, mas devido à falta ou a divergências de estudos específicos sobre seus efeitos no tecido ósseo, sua utilização sobre as regiões distais dos membros, ricas em protuberâncias ósseas e áreas desprovidas de cobertura muscular, sempre preocuparam os profissionais da área médica. No intuito de esclarecer os efeitos do UST sobre o tecido ósseo, seis cães receberam tratamento ultra-sônico contínuo, de 1MHz, durante cinco minutos diários, por um período de 20 dias sobre a região craniodistal do rádio e da ulna. A intensidade do UST aplicada foi de 0,5W cm-2 no membro torácico direito, ficando o membro contralateral como controle. A região distal de ambos os membros torácicos foi radiografada para análise de densitometria óssea em imagens radiográficas, antes do início da terapia e ao final do tratamento. Não houve alterações significativas de densidade mineral óssea entre os membros tratados e os controles. Conclui-se que dentro dos parâmetros utilizados no experimento a utilização do UST em regiões ósseas protuberantes ou desprovidas de cobertura muscular pode ser feita com segurança.

Tendon lesions on distal extremities of the limbs are among the most frequent alterations of the locomotor system in the human and animal clinic-surgery routine, and frequently need supplementary therapy for the complete recovery of the physiologic functions. The therapeutic ultrasound (TUS) is the mostly used apparatus in rehabilitation clinics to treat tendon lesions, but due to the lack or the divergence on specific studies about its effects in bone tissues, the use of TUS in distal regions of the members, which are rich in bony protuberances and muscle-less areas, always concern the medical professionals. For the purpose of enlightening the TUS effects on bone tissue, six dogs received a continuous ultrasound treatment of 1MHZ for 5 minutes per day on distal-skull area of radio and ulna during 20 days. The TUS intensity applied was 0.5W cm-2 in the right thoracic member leaving out the counter-lateral member for control. Before the beginning and in the end of the treatment, the distal area of both thoracic members were radiographed for analysis of bone densitometry in radiographic images. There wasn't any significant alteration in bone mineral density between the treated members and the control members. Based on the parameters used in this experiment one can conclude that the use of TUS in bony protuberances and muscle-less areas can be done with safety.