Ultrasound effect on level of stress proteins and arthritic histology in experimental arthritis

Effects of Therapeutic Ultrasound Applied to the Lumbar Region on Renal Function: A Randomized Controlled Prospective Trial

OBJECTIVES

Therapeutic ultrasound (TUS) is one of the most commonly used modalities in low back pain treatment. The objective of this study was to determine whether TUS applied to the low back region in patients with chronic low back pain had any effect on renal function.

METHODS

Forty patients with chronic low back pain were randomized to 2 groups by a block randomization method. Thirty-seven patients completed the final evaluation. All patients were treated for 5 sessions per week for 3 weeks with the same physiotherapy modalities (superficial heating and transcutaneous electrical nerve stimulation) and exercise therapy; in addition to these treatments, the second group was treated with TUS for 10 minutes (frequency, 1 MHz; intensity, 1.5 W/cm² ; and effective irradiation area of the transducer head, 5 cm² ). The serum creatinine, serum cystatin C, 24-hour urine creatinine, creatinine clearance, 24-hour urine microalbumin and microprotein, urine volume, and glomerular filtration rate were measured. The patients were evaluated at baseline (day 0) and the end of the treatment (day 21).

RESULTS

The serum cystatin C levels were increased in both groups, but this increase was not significant (P > .05). There was no difference between the groups in the percent change in all outcome measures (P > .05).

CONCLUSIONS

This showed that TUS applied to the low back region does not affect renal function.

Efficacy of extracorporeal shockwave therapy and low-intensity pulsed ultrasound in a rat knee osteoarthritis model: A randomized controlled trial

OBJECTIVE

This study aims to assess the efficacy of extracorporeal shockwave therapy (ESWT) and low-intensity pulsed ultrasound (LIPUS) on osteoarthritic rat knees.

MATERIAL AND METHODS

Twenty-four rats were divided into 3 groups: group 1-control (n=8), group 2-LIPUS (n=8) and group 3-ESWT (n=8). Cartilage degeneration was provided using mono-iodo-asetate (MIA). One milligram of MIA was delivered to the right knees in group 1 and both knees in group 2 and 3. A 0.09% saline solution was delivered to the left knees in group 1 for control. Twenty-four hours after the delivery, ESWT was applied once on the right knees in the group 2 rats to the medial tibia plateu with a 1 Hz frequency and 800 impulses. LIPUS was applied to the right knees in the group 2 rats to the medial tibia plateu with a 3 mHz frequency and 40 mW/cm2 intensity for 20 minutes over a period of 15 days. Pain scores were measured with a knee bend test. Bone mineral density measurements and scintigraphic bone scans were performed. Histopathological examination was done using a modified Mankin scale.

RESULTS

There was no difference among the right knee subchondral bone osteoblastic activities (p>0.05). The left knee osteoblastic activities in the LIPUS and extracorporeal shockwave therapy (ESWT) groups were higher than those in the control group (p<0.05), but there was no difference between the LIPUS and ESWT groups. There was no difference among the groups for both knee subchondral bone BMD values (p>0.05). The modified Mankin scores of both the right and left knees of the ESWT and LIPUS groups were lower than those of the control group (p<0.05), but there was no difference between the ESWT and LIPUS groups. The pain scores of both knees of the ESWT and LIPUS groups at day 7 were higher than those of the control group (p<0.05), but there was no difference between the ESWT and LIPUS groups. There was no difference among the pain scores of the right knees at day 14 (p<0.05).

CONCLUSION

ESWT and LIPUS have systemic proliferative and regenerative effects on cartilage and tissue.

Efficacy of focused low-intensity pulsed ultrasound therapy for the management of knee osteoarthritis: a randomized, double blind, placebo-controlled trial

The aim of this study was to investigate the effects of focused low-intensity pulsed ultrasound (FLIPUS) therapy on the functional and health status of patients with knee osteoarthritis (KOA). A total of 106 subjects with bilateral KOA were randomized sequentially into two groups. Group I received FLIPUS + diclofenac sodium, and group II received sham FLIPUS + diclofenac sodium. The therapeutic effects of the interventions were evaluated by measuring changes in VAS pain, the WOMAC scores, and the LI scores after 10 days of treatment as well as changes in LI and VAS at follow-up, 4 and 12 weeks later. In addition, changes in the range of motion, ambulation speed, and the SF-36 in each group were recorded after 10 days of treatment. Compared with those in group II, patients in group Ishowed significant improvements in VAS, WOMAC, LI, ambulation speed, and most items in the SF-36 after 10 days of treatment. In addition, patients in group I showed significant improvements in LI and VAS at follow-up. There were no FLIPUS-related adverse events during and after the interventions. In conclusion, FLIPUS is a safe and effective treatment modality for relieving pain and improving the functions and quality of life of patients with KOA.

Therapeutic Ultrasound in Lower Extremity Wound Management

In medical practice, ultrasound (US) is used for diagnosis and therapy. High-frequency (1-4 MHz) and low-frequency (20-120 KHz) therapeutic US are relevant to wound healing. The heating effects of high-frequency US are important, whereas the mechanical effects of low-frequency US must be considered. The physiological effects of low-frequency US include metabolic enhancement, perfusion, wound cleansing, and the acceleration of wound granulation. The therapeutic efficacy of US depends on dose (W/cm2 time)and dosage (frequency of application, series). At adequate doses, high-frequency and low-frequency therapeutic US induce in vitro cell proliferation; protein synthesis; and the production of cytokines by fibroblasts, osteoblasts, and monocytes. The mechanical effects of low-frequency US cause transient cavitation in wound surfaces for soft and smooth wound cleaning, ulcer debridement, and the stimulation of granulation. These effects can be determined in clinical studies, though the quality of the studies done so far and of the evidence of the usefulness of US is poor. Nevertheless, high-frequency and low-frequency US may be reasonable options in the management of chronic wounds.

Focused Low-intensity Pulsed Ultrasound Affects Extracellular Matrix Degradation via Decreasing Chondrocyte Apoptosis and Inflammatory Mediators in a Surgically Induced Osteoarthritic Rabbit Model

We investigated whether focused low-intensity pulsed ultrasound (FLIPUS) affects extracellular matrix (ECM) production in osteoarthritic (OA) rabbits by decreasing chondrocyte apoptosis and pro-inflammatory mediators. An OA model using New Zealand White rabbits (N = 30) and 30 normal rabbits were randomized into three groups (2-, 4- and 8-wk groups; n = 10 knees each). A knee from each rabbit was randomly selected to receive FLIPUS and the other knee received a sham treatment as a control. Another 30 normal rabbits were blank controls. We measured ECM degradation, joint effusion volume and levels of prostaglandin E2 and nitric oxide. Also, ratios of chondrocyte proliferation and apoptosis were calculated. Compared with sham stimulation, FLIPUS attenuated release of type II collagen and proteoglycans and reduced chondrocyte apoptosis as well as total joint effusion volume and significantly alleviated OA-induced accretion of prostaglandin E2 and nitric oxide in the synovial fluid. FLIPUS application promoted ECM production in OA through down regulation inflammatory mediators, joint effusion volume and chondrocyte apoptosis.

Low-Intensity Pulsed Ultrasound Affects Chondrocyte Extracellular Matrix Production via an Integrin-Mediated p38 MAPK Signaling Pathway

Although low-intensity pulsed ultrasound (LIPUS) regulates p38 mitogen-activated protein kinase (MAPK) and promotes cartilage repair in osteoarthritis, the role of integrin-mediated p38 MAPK in the effect of LIPUS on extracellular matrix (ECM) production of normal and OA chondrocytes remains unknown. The aim of this study was to investigate whether LIPUS affects ECM production in normal and OA rabbit chondrocytes through an integrin-p38 signaling pathway. A rabbit model of OA was established by anterior cruciate ligament transection, and chondrocytes were isolated from normal or OA cartilage and cultured in vitro. Chondrocytes were treated with LIPUS and then pre-incubated with the integrin inhibitor GRGDSP or the p38 inhibitor SB203580. Expression of type II collagen, MMP-13, integrin β1, p38 and phosphorylated p38 was assessed by Western blot analysis. We found that type II collagen and integrin β1 were upregulated (p < 0.05), whereas MMP-13 was downregulated (p < 0.05) in normal and OA chondrocytes. Furthermore, phosphorylated p38 was upregulated (p < 0.05) in normal chondrocytes, but downregulated (p < 0.05) in OA chondrocytes after LIPUS stimulation. Pre-incubation of chondrocytes with the integrin inhibitor disrupted the effects of LIPUS on normal and OA chondrocytes. Pre-incubation of chrondocytes with the p38 inhibitor reduced the effects of LIPUS on normal chondrocytes, but had no impact on OA chondrocytes. Our findings suggest that the integrin-p38 MAPK signaling pathway plays an important role in LIPUS-mediated ECM production in chondrocytes.

Sustained Acoustic Medicine: A Novel Long Duration Approach to Biomodulation Utilizing Low Intensity Therapeutic Ultrasound

Therapeutic ultrasound is an established technique for biomodulation used by physical therapists. Typically it is used to deliver energy locally for the purpose of altering tissue plasticity and increasing local circulation. Access to ultrasound therapy has been limited by equipment and logistic requirements, which has reduced the overall efficacy of the therapy. Ultrasound miniaturization allows for development of portable, wearable, self-applied ultrasound devices that sidestep these limitations. Additionally, research has shown that the timescale of acoustic stimulation matters, and directly affects the quality of result. This paper describes a novel, long duration approach to therapeutic ultrasound and reviews the current data available for a variety of musculoskeletal conditions.

Effectiveness of continuous and pulsed ultrasound for the management of knee osteoarthritis: a systematic review and network meta-analysis

BACKGROUND

To investigate the efficacy of continuous and pulsed ultrasound (US) in the management of knee osteoarthritis (OA).

DESIGN

This systematic review and network meta-analysis covered 12 trials in total. Electronic databases including MEDLINE, Embase and Cochrane Library were searched through to identify randomized controlled trials comparing the two modes of US with control interventions (sham or blank) or with each other. Bayesian network meta-analysis was used to integrate both the direct and indirect evidences on treatment effectiveness.

RESULTS

Pulsed US (PUS) is more effective in both pain relief and function improvement when compared with the control group; but for continuous US (CUS), there is only a significant difference in pain relief in comparison with the control group. In addition, no matter in terms of pain intensity or function at the last follow-up time point, PUS always exhibited a greater probability of being the preferred mode. However, the evidence of heterogeneity and the limitation in sample size of some studies could be a potential threat to the validity of results.

CONCLUSIONS

Our findings indicated that PUS, with a greater probability of being the preferred mode, is more effective in both pain relief and function improvement when compared with the control group. However, CUS could only be considered as a pain relief treatment in the management of knee OA. The findings also confirmed that none of these modes is dangerous.

LEVEL OF EVIDENCE

Level II, systematic review and network meta-analysis of randomized controlled trials.

Effects of low-intensity pulsed ultrasound on integrin-FAK-PI3K/Akt mechanochemical transduction in rabbit osteoarthritis chondrocytes

The effect of low-intensity pulsed ultrasound (LIPUS) on extracellular matrix (ECM) production via modulation of the integrin/focal adhesion kinase (FAK)/phosphatidylinositol 3-kinase (PI3K)/Akt pathway has been investigated in previous studies in normal chondrocytes, but not in osteoarthritis (OA). Therefore, we investigated the LIPUS-induced integrin β1/FAK/PI3K/Akt mechanochemical transduction pathway in a single study in rabbit OA chondrocytes. Normal and OA chondrocytes were exposed to LIPUS, and mRNA and protein expression of cartilage, metalloproteinases and integrin-FAK-PI3K/Akt signal pathway-related genes was determined by quantitative reverse transcription polymerase chain reaction and Western blotting, respectively. Compared with levels in normal chondrocytes, expression levels of ECM-related genes were significantly lower in OA chondrocytes and those of metalloproteinase-related genes were significantly higher. In addition, integrin β1 gene expression and the phosphorylation of FAK, PI3K and Akt were significantly higher in OA chondrocytes. The expression of all tested genes was significantly increased except for that of metalloproteinase, which was significantly decreased in the LIPUS-treated OA group compared to the untreated OA group. LIPUS may affect the integrin-FAK-PI3K/Akt mechanochemical transduction pathway and alter ECM production by OA chondrocytes. Our findings will aid the future development of a treatment or even cure for OA.

Effects of low-intensity pulsed ultrasound and hyperbaric oxygen on human osteoarthritic chondrocytes

Background

Although the individual effects of hyperbaric oxygen (HBO) and low-intensity pulsed ultrasound (LIPUS) on osteoarthritic (OA) chondrocytes have been reported, the effects of HBO combined with LIPUS treatment are unknown.

Methods

OA chondrocytes were obtained from patients undergoing knee replacement surgery. RNA was isolated for real-time polymerase chain reaction (PCR) analysis of inducible nitric oxide synthase (iNOS), type-II collagen, and aggrecan gene expression. The protein levels of MMP-3 and TIMP-1 were quantified by enzyme-linked immunosorbent assay (ELISA) after LIPUS or HBO treatment. The data are given as mean ± standard deviation (SD) of the results from three independent experiments. A p value less than 0.05 was defined as statistically significant.

Results

Our data suggested that ultrasound and HBO treatment increased cell bioactivity of OA chondrocytes. Real-time PCR analysis showed that HBO treatment increased the mRNA of type-II collagen, aggrecan, and TIMP-1 but suppressed the iNOS expression of OA chondrocytes. LIPUS treatment increased the type-II collagen and iNOS expression of OA chondrocytes. ELISA data showed that HBO or LIPUS treatment increased TIMP-1 production of OA chondrocyte. MMP-3 production was suppressed by HBO treatment. HBO combined with LIPUS treatments resulted in additive effect in TIMP-1 production and compensatory effect in iNOS expression.

Conclusion

HBO combined with LIPUS treatment-induced increase of the anabolic factor (TIMP-1)/catabolic factor (MMP-3) ratio may provide an additive therapeutic approach to slow the course of OA degeneration.

Design and evaluation of a wearable self-applied therapeutic ultrasound device for chronic myofascial pain

Ultrasound therapy for pain and healing is a versatile treatment modality for musculoskeletal conditions that is used daily in rehabilitation clinics around the world. Our group designed and constructed a wearable, battery-operated, low-intensity therapeutic ultrasound (LITUS) device that patients could self-apply and operate during daily activity for up to 6 h. Thirty patients with chronic trapezius myofascial pain evaluated the LITUS system in a double-blind, placebo-controlled, 10-d study under institutional review board approval. While continuing their prescribed medication regimen, patients with the active device reported on average 1.94× reduction in pain and 1.58× improvement in health relative to placebo devices after 1 h of treatment. Both of these results were statistically significant (p < 0.05) for the first 2 d of the study. Male patients reported the majority of benefit, and there is a sex-treatment confound in the sample. The study indicates that wearable, long-duration LITUS technology improves mobile access to drug-free pain relief.

Physical therapists in primary care are interested in high quality evidence regarding efficacy of therapeutic ultrasound for knee osteoarthritis: a provincial survey

Recent high-level evidence favours therapeutic ultrasound (US) for reducing pain in people with knee osteoarthritis (OA). It is unknown how current practice patterns align with current evidence regarding US efficacy and whether physical therapists perceive a need for further high-level evidence. We conducted a descriptive electronic survey to characterize the beliefs and use of US among physical therapists in Ontario treating people with nonsurgical knee OA. Most of the 123 respondents (81%) reported at least some use of US with 45% using it often or sometimes. The main goal for using US was to reduce pain in the surrounding soft tissue (n = 66) and/or the knee joint (n = 43). Almost half (46%) endorsed the belief that US is likely to be beneficial for clients with nonsurgical knee OA. Most respondents (85%) expressed interest in the results of a randomized controlled trial evaluating the effectiveness of US on pain and physical function. Patterns of use reflect the respondents' belief that US is likely to be beneficial for knee OA pain.

Effect of low-intensity pulsed ultrasound on the cartilage repair in people with mild to moderate knee osteoarthritis: a double-blinded, randomized, placebo-controlled pilot study

Recent high-level evidence favours therapeutic ultrasound (US) for reducing pain in people with knee osteoarthritis (OA). It is unknown how current practice patterns align with current evidence regarding US efficacy and whether physical therapists perceive a need for further high-level evidence. We conducted a descriptive electronic survey to characterize the beliefs and use of US among physical therapists in Ontario treating people with nonsurgical knee OA. Most of the 123 respondents (81%) reported at least some use of US with 45% using it often or sometimes. The main goal for using US was to reduce pain in the surrounding soft tissue (n = 66) and/or the knee joint (n = 43). Almost half (46%) endorsed the belief that US is likely to be beneficial for clients with nonsurgical knee OA. Most respondents (85%) expressed interest in the results of a randomized controlled trial evaluating the effectiveness of US on pain and physical function. Patterns of use reflect the respondents' belief that US is likely to be beneficial for knee OA pain.

Effect of low-intensity pulsed ultrasound on the cartilage repair in people with mild to moderate knee osteoarthritis: a double-blinded, randomized, placebo-controlled pilot study

OBJECTIVE

To determine the feasibility of conducting a randomized controlled trial assessing the effect of low-intensity pulsed ultrasound (US) therapy on cartilage repair in patients with mild to moderate knee osteoarthritis (OA).

DESIGN

Pilot, double-blinded, randomized placebo-controlled trial with 2-months follow-up.

SETTING

Rehabilitation research facility.

PARTICIPANTS

Adults (N=27; ≥45y) with grades 1 or 2 of medial joint space narrowing (Osteoarthritis Research Society International atlas) due to knee OA were randomly allocated to receive active (n=14) or sham (n=13) US therapy. Four participants withdrew for personal reasons.

INTERVENTIONS

Twenty-four sessions of active (20% duty cycle, 1MHz, average temporal intensity: 0.2W/cm(2), therapeutic dose: 112.5J/cm(2)) or sham (no sound-head crystal) US therapy.

MAIN OUTCOME MEASURES

Success of recruitment and adherence rates were established by a priori criteria. Effect on cartilage repair was assessed by measuring cartilage volume and thickness and scoring cartilage injury, subchondral cyst formation, and bone marrow lesions on magnetic resonance images.

RESULTS

Patient recruitment and adherence rates were successful. No significant age-adjusted differences were seen between groups in the cartilage repair outcomes. Age-adjusted analyses, including only subjects who attended 20 sessions or more, showed an increase in medial tibia cartilage thickness in the active US therapy group (90μm; 95% confidence interval, 1-200; P=.05).

CONCLUSIONS

Conducting a randomized controlled trial to assess the effects of US therapy on the cartilage repair in people with mild to moderate knee OA is feasible. However, further pilot studies are needed to determine the optimal US dose and application parameters before designing a full trial.

The effect of therapeutic ultrasound on metallic implants: a study in rats

OBJECTIVE

To investigate whether therapeutic ultrasound (US) use over metallic implants has the potential for adverse effects as a result of greater temperature increases at the tissue-metal interface.

DESIGN

A randomized controlled trial.

SETTING

A research laboratory.

ANIMALS

Sprague-Dawley rats (N=40; weight, 230-300g) were used and divided into 3 study groups.

INTERVENTIONS

In group 1, both limbs of 10 rats were used for evaluation of temperature changes. Metal pins were placed into the femur of the left limb, and the right limbs were used as controls. A thermal sensor was placed into the medulla to record the elevation of tissue temperature during US application. In groups 2 and 3 with 15 rats in each, a midshaft femoral fracture was produced, and intramedullary fixation was performed with metal pins. Group 2 received US treatment for 5 minutes daily and continued for 27 days. Group 3 served as controls.

MAIN OUTCOME MEASURES

The rats in groups 2 and 3 were killed on postoperative day 30. The specimens were evaluated by radiology, histopathology, and biomechanics.

RESULTS

The presence of metal in bone did not cause an increased temperature rise. US application did not increase or decrease callus formation, and there was no tissue necrosis. The average removal torques of pins in groups did not show a significant difference.

CONCLUSIONS

Internal fixation with metallic implants may not be a contraindication for therapeutic US treatment.

Modification of osteoarthritis in the guinea pig with pulsed low-intensity ultrasound treatment

OBJECTIVE

The Hartley guinea pig develops articular cartilage degeneration similar to that seen in idiopathic human osteoarthritis (OA). We investigated whether the application of pulsed low-intensity ultrasound (PLIUS) to the Hartley guinea pig joint would prevent or attenuate the progression of this degenerative process.

METHODS

Treatment of male Hartley guinea pigs was initiated at the onset of degeneration (8 weeks of age) to assess the ability of PLIUS to prevent OA, or at a later age (12 months) to assess the degree to which PLIUS acted to attenuate the progression of established disease. PLIUS (30 mW/cm(2)) was applied to stifle joints for 20 min/day over periods ranging from 3 to 10 months, with contralateral limbs serving as controls. Joint cartilage histology was graded according to a modified Mankin scale to evaluate treatment effect. Immunohistochemical staining for interleukin-1 receptor antagonist (IL-1ra), matrix metalloproteinase (MMP)-3, MMP-13, and transforming growth factor (TGF)-beta1 was performed on the cartilage to evaluate patterns of expression of these proteins.

RESULTS

PLIUS did not fully prevent cartilage degeneration in the prevention groups, but diminished the severity of the disease, with the treated joints showing markedly decreased surface irregularities and a much smaller degree of loss of matrix staining as compared to controls. PLIUS also attenuated disease progression in the groups with established disease, although to a somewhat lesser extent as compared to the prevention groups. Immunohistochemical staining demonstrated a markedly decreased degree of TGF-beta1 production in the PLIUS-treated joints. This indicates less active endogenous repair, consistent with the marked reduction in cartilage degradation.

CONCLUSIONS

PLIUS exhibits the ability to attenuate the progression of cartilage degeneration in an animal model of idiopathic human OA. The effect was greater in the treatment of early, rather than established, degeneration.

Expression of heat shock proteins after ultrasound exposure in HL-60 cells

One of the important cellular defense mechanisms against stress is the induction of heat shock proteins (HSPs). We have recently demonstrated that a low frequency electromagnetic field is unable to induce the heat shock response (HSR). In the present study, we expanded our investigations to the induction of HSPs, particularly Hsp72, by ultrasound (US). Human promyelocytic leukemia HL-60 cells were exposed in suspension to US at 1, 3 and 10 MHz, as well as combinations of two of these frequencies. The ability of US to induce Hsp72 was tested for different frequencies, intensities and exposure times. In addition, the water bath temperature was varied from 30 to 36 degrees C. The Hsp72 protein expression was determined 4 and 24 h after treatment. We found that the amount of Hsp72 increased with increasing US frequency, reaching its highest level of about 1800%, induced by 10 MHz. After increasing the temperature of the water bath, the amount of Hsp72 in the treated cells was also increased, whereas no induction was observed at 30 degrees C. For all treatment conditions, ultrasound of 1 MHz was unable to significantly induce Hsp72. At 10 MHz, the exposure time was varied from 0 to 20 min. We found that the induction of Hsp72 took place after 5 min of exposure. For a fixed level of absorbed US energy, the continuous regime, as well as a pulsation of 1:2 (5 ms on and 5 ms off) induced the same Hsp72 level. Pulsation of 1:5 (2 ms on and 8 ms off) and 1:10 (1 ms on and 9 ms off) did not show any effect. A single sonication of 20 min, as well as a fractionated sonication of two 10 min exposures induced the same level of Hsp72, whereas four exposures of 5 min reduced the Hsp72 level. At the optimum exposure conditions (10 MHz, 10 min), the concentration of other HSPs was also determined. Hsp27 showed no effect but Hsp32, Hsp40 and Hsp72 were induced. Taken together, these results suggest a synergistic interaction between heat and US.

Effects of pulsed low-intensity ultrasound on human child chondrocytes

The effect of pulsed low-intensity ultrasound (PLIUS) on human articular chondrocytes was evaluated in an in vitro 3-D agarose gel culture model. Chondrocytes isolated from young children's articular cartilage of ablated polydactylia were embedded in gel after expansion and exposed to PLIUS on the third day after embedding. Another group of cells was exposed to sham PLIUS as a control. Different intensities of PLIUS treatment-18 mW/cm(2), 48 mW/cm(2), 72 mW/cm(2) and 98 mW/cm(2) (1.0 MHz, with burst duration of 200 micros repeated at 1.0 kHz)-were administered for 20 min/d, and the medium was replaced twice a week. The cultures were evaluated for aggrecan synthesis by enzyme-linked immunosorbent assay (ELISA), type II collagen production by Western blotting or ELISA and cell proliferation by total DNA measurement. The PLIUS was found to increase aggrecan synthesis in a time-dependent manner. The maximal response was observed at an intensity of 48 mW/cm(2). After 14 d of exposure at this intensity, the aggrecan synthesis was 214 +/- 26% of control, and type II collagen synthesis was 148.5 +/- 8.0% of control. However, PLIUS treatment revealed no significant influence on cell proliferation, confirming that the stimulation of aggrecan and type II collagen synthesis by PLIUS was not the result of an increase in chondrocyte cell proliferation. In addition, it was found that human chondrocytes harvested from older donors become less responsive to PLIUS. From this in vitro 3-D study of cultured human chondrocytes, our findings suggest that PLIUS may be applied to the tissue engineering of cartilage constructs.

Heat Shock Protein Expression in Rat Skeletal Muscle After Repeated Applications of Pulsed and Continuous Ultrasound

OBJECTIVE

To determine whether repeated ultrasound treatments are capable of increasing the expression of heat shock protein (HSP) 72 and HSP 25 in rat skeletal muscles.

DESIGN

In vivo, experimental, controlled study.

SETTING

Animal laboratory.

ANIMALS

Male Sprague-Dawley rats (n=9).

INTERVENTIONS

Ultrasound (1MHz, 15 min, 2.0 cm2 transducer) continuous at 1.0 W/cm2 spatial average temporal average intensity (CONTUS) or pulsed at 2.0 W/cm2 spatial average temporal peak intensity 50% duty cycle (PULS50) was applied on 4 consecutive days to the lower leg muscles of 1 hindlimb in each rat (n=9).

MAIN OUTCOME MEASURES

Twenty-four hours after the final ultrasound application, hindlimb muscles were removed, weighed, and assessed for HSP 72 and HSP 25 content by Western blotting. Bands from blots were quantified and data were assessed using t tests (alpha=.05).

RESULTS

Ultrasound did not affect core or contralateral hindlimb muscle temperature. Average muscle temperatures during the final day ultrasound treatments were 38.71 degrees +/-0.30 degrees C when using PULS50 and 38.16 degrees +/-0.57 degrees C when using CONTUS. PULS50 significantly increased HSP 25 content in the plantaris and soleus muscles and HSP 72 content in the plantaris muscles. CONTUS significantly increased HSP 72 content in the white gastrocnemius muscle.

CONCLUSIONS

HSPs can be induced in skeletal muscle when ultrasound is used on a repeated basis to treat soft tissue.

Effects of low-intensity ultrasound (LIUS) stimulation on human cartilage explants

OBJECTIVE

To evaluate the effects of low-intensity ultrasound (LIUS) stimulation on the anabolic state of human cartilage from patients with osteoarthritis (OA).

METHODS

Explant cultures of human OA cartilage were stimulated for 10 min every day for 7 consecutive days using continuous-wave sonication at a frequency of 1 MHz with spatial and temporal average intensities of 0 (control), 40, 200, 500, or 700 mW/cm2. The effects of LIUS on cell proliferation were evaluated by 3H-thymidine incorporation. Proteoglycan synthesis was evaluated by the incorporation of 35S-sulfate and by Safaranin O staining. Collagen synthesis was evaluated by 3H-proline incorporation and immunohistochemistry.

RESULTS

At an intensity of 200 mW/cm2, LIUS treatment induced the expression of collagen type II and proteoglycan measured by the incorporation of radioactivity and specific staining of the cartilage explants. However, the expression decreased again at the higher intensities of 500 or 700 mW/cm2. Ultrasound had no stimulatory effect on cell proliferation at any intensity.

CONCLUSION

LIUS has anabolic effects on human cartilage in explant cultures, indicating a potentially important method for the repair of osteoarthritic cartilage.

Exposure to pulsed low intensity ultrasound stimulates extracellular matrix metabolism of bovine intervertebral disc cells cultured in alginate beads

STUDY DESIGN

In vitro study on the effects of pulsed low intensity ultrasound on the cellular metabolism of bovine intervertebral disc cells.

OBJECTIVE

To determine whether pulsed low intensity ultrasound has effects on cell proliferation and extracellular matrix metabolism by bovine intervertebral disc cells.

SUMMARY OF BACKGROUND DATA

The application of pulsed low intensity ultrasound is known to be effective in stimulating fracture and cartilage repair. However, the effects of pulsed low intensity ultrasound on intervertebral disc cells are not known.

METHODS

Cells of the nucleus pulposus and inner and outer anulus fibrosus were enzymatically isolated from bovine coccygeal tissue and precultured in alginate beads for 14 days. In the ultrasound group, pulsed low intensity ultrasound was administered to the culture for 20 minutes daily for an additional 20 days. The control group was cultured in the same way but without administration of ultrasound. Cell viability, DNA content, proteoglycan and collagen synthesis, and proteoglycan content at days 10 and 20 after the initiation of treatment were evaluated. Characterization of newly synthesized collagen and proteoglycan was performed.

RESULTS

No significant differences in cell viability and DNA content were observed between the two groups. On day 20, proteoglycan synthesis was increased by the application of pulsed low intensity ultrasound in nucleus pulposus and inner and outer anulus fibrosus cells (24%-26% increase, P < 0.001). The application of pulsed low intensity ultrasound increased proteoglycan content in alginate beads containing inner and outer anulus fibrosus cells (P < 0.05). Collagen synthesis by cells isolated from all three zones of the intervertebral disc was increased by the application of pulsed low intensity ultrasound (16%-19% increase, P < 0.05-0.0001).

CONCLUSIONS

The application of pulsed low intensity ultrasound stimulated extracellular matrix metabolism in intervertebral disc cells. Pulsed low intensity ultrasound may prove useful for the physical stimulation of cell metabolism for tissue engineering of intervertebral disc tissue.

The effect of sonication on simulated osteoarthritis. Part II: alleviation of osteoarthritis pathogenesis by 1 MHz ultrasound with simultaneous hyaluronate injection

In our previous study, we demonstrated the effects of ultrasound (US) on the delivery of hyaluronan (HA) into the synovium, even at molecular sizes as high as 3000 kDA. We hypothesized that a combined therapy with US and HA would have synergistic effects on alleviating the pathogenesis of osteoarthritis (OA). In the present study, we evaluated the effectiveness of sonication on the progress of induced OA in rabbits. We measured the cartilage degradation and inflammation, synovial fluid amount along with protein content and, finally, performed histologic analyses of the integrity of the cartilage and synovium. Low-intensity continuous US at 1 MHz, 400 mW/cm2 was applied to the knees for 10 min bid. Combined treatment with US and HA most strikingly reduced total synovial fluid volume and also significantly alleviated the OA-induced accretion of total protein, proteoglycan and prostaglandin E2 in the synovial fluid. It also attenuated the release of collagen type II and matrix metalloproteinase-3 in the OA-induced joint to normal levels. Histopathology revealed that combined HA and US treatment also reduced the severity of OA-induced structural damages in the cartilage and synovium. The effectiveness of HA with regard to the alleviation of OA pathogenic changes can be greatly enhanced by the simultaneous treatment with HA and US.

Effects of Helium-Neon Laser on Levels of Stress Protein and Arthritic Histopathology in Experimental Osteoarthritis

OBJECTIVE

To investigate the effect of low-power laser therapy on levels of stress proteins (SPs) in experimental arthritis and their relation to the bioeffects on arthritic cartilage repair.

DESIGN

A total of 42 rats with similar degrees of induced arthritis evaluated by means of bone scan were divided randomly into two groups. In the treated group, 21 rats received helium-neon laser treatment; in the control group, 21 rats received sham laser treatment. The changes in chondrocytes of SPs were measured by electrophoresis of proteins extracted from chondrocytes of arthritic cartilage at various time periods. The histopathologic changes and the presence of SP of arthritic cartilage were identified by hematoxylin and eosin stain and by immunostains of SP72 antibody individually from frozen sections of arthritic cartilage.

RESULTS

SP density increased markedly in rats after laser treatment and was closely related to the repair of arthritic cartilage. Furthermore, the pathohistology of arthritic cartilage improved significantly with the decline of SP levels in the follow-up period.

CONCLUSION

Helium-neon (632 nm) low-power laser can enhance SP production in arthritic chondrocytes. The extragenic production of SP is well correlated with the therapeutic effect of low-power laser in preserving chondrocytes and the repair of arthritic cartilage in rats.

The effects of pulsed low-intensity ultrasound on chondrocyte viability, proliferation, gene expression and matrix production

This study was designed to examine the effects of pulsed low-intensity ultrasound (PLIUS) on chondrocyte viability, proliferation, matrix production and gene expression. Chondrocytes were isolated from the distal part of the sternum of 16-day-old chick embryos and cultured in alginate beads. PLIUS at 2 mW/cm(2) (group PLIUS(2)) and 30 mW/cm(2) (group PLIUS(30)) was applied to chondrocytes for a single 20-min treatment. A control group was treated without PLIUS. The viability of chondrocytes was not affected by exposure to PLIUS. PLIUS influenced chondrocyte proliferation in an intensity-dependent manner. By day 7 after application of PLIUS, the gene expression and synthesis of aggrecan was the same as in the controls. At this same time point, the expression and synthesis of type II collagen was not different between the controls and PLIUS(30), but was increased in PLIUS(2). PLIUS was shown to inhibit the expression of type X collagen. This inhibition of chondrocyte hypertrophy may prove to be significant in the management of cartilage degeneration.

Continuous and pulsed ultrasound do not increase heat shock protein 72 content

Therapeutic ultrasound (US) is a common treatment used in the rehabilitation of injured muscle. To determine whether therapeutic US could increase the content of heat shock protein (HSP) 72 in skeletal muscle, male Sprague-Dawley rats were anesthetized and the muscles from one hind limb treated with 15 min of US at 1 MHz using either: 1. continuous US at 1.0 W/cm(2), 2. pulsed US at 2.0 W/cm(2) at 50% duty cycle, or 3. pulsed US at 1.0 W/cm(2) at 20% duty cycle. All treatments were applied using a transducer (1.6-cm diameter) on an area of the rat hind limb twice the size of the sound head. At 24 h following treatment, the plantaris, soleus, white and red gastrocnemius muscles were removed and assessed for HSP 72 content by Western blotting. No significant increases in HSP 72 content were detected in any of the muscles examined following any US treatment. These results suggest muscle HSP content is not elevated following a typical therapeutic dose of either continuous or pulsed US in the rat.