Effect of Bipolar Radiofrequency Energy on Canine Stifle Joint Fluid Temperature.

OBJECTIVE: The aim of this study was to evaluate the effect of bipolar radiofrequency (RF) energy on canine stifle joint fluid temperature. MATERIALS AND METHODS: A standard stifle arthroscopy was performed on 15 canine large breed cadaveric stifle joints. A bipolar RF (VAPR III, 2.3-mm side effect electrode; Depuy Mitek, Raynham, Massachusetts, United States) unit was activated in the joint (1) with or without direct tissue contact, (2) with or without additional 18-gauge needle outflow and (3) for 15 and 30 seconds. The joint fluid temperature was monitored with two fibre optic intra-articular sensors. RESULTS: The stifle joint fluid temperature was significantly higher when there was no contact between the tissue and RF probe (mean: 58.6°C with 95% confidence interval [CI]: 53.3-64.0°C) compared with when tissue was contacted (mean: 29.0°C with 95% CI: 26.3-31.6°C). An 18-gauge egress needle had minimal effect on reducing joint fluid temperature. The temperature was higher during the 30-second application of RF energy than the 15-second group. CLINICAL SIGNIFICANCE: Bipolar RF energy without firm tissue contact rapidly and significantly increased joint fluid temperature beyond the level reported to damage chondrocytes (above 45°C). Caution is required in the use of bipolar RF energy in the canine stifle joint.

The effect of low-level laser to apoptosis of chondrocyte and caspases expression, including caspase-8 and caspase-3 in rabbit surgery-induced model of knee osteoarthritis.

The purpose of this study was to observe the effect of 810-nm low-level laser to apoptosis of chondrocyte and related proteins, including caspase-3 and caspase-8, in rabbit surgery-induced model of knee osteoarthritis. A total of 24 New Zealand White rabbits were randomly assigned into 3 groups: test group, model group, and normal group. The rabbits in test group and model group received anterior cruciate ligament transection in the right knee. Six weeks after transection, the rabbits in test group were given 10-session 810-nm laser illumination. Eight weeks after transection, all animal were killed. Modified Mankin Score was made for histological assessment. The caspases expressions and chondrocytes apoptosis were tested using the immunohistochemistry and TUNEL assessment, respectively. The modified Mankin Score of test group was significantly lower than model group (P < 0.01) and higher than normal group (P < 0.01). The caspase-8 expression of test group was lower than model group and higher than normal group, but no significant difference was found (P > 0.05). This study revealed that the 810-nm low-level laser can improve cartilage structure, prevent articular cartilage degradation and significantly decrease the expression of caspase-3 in this surgery-induced OA model. Further studies are needed.

Effects of pulsed electromagnetic fields on cartilage apoptosis signalling pathways in ovariectomised rats.

PURPOSE: The purpose of this study was to determine the effect of exposure to pulsed electromagnetic fields (PEMF) on modulation of the cartilage apoptosis signalling pathway in ovariectomised rats by monitoring the expression of mRNA of X-linked inhibitor of apoptosis protein (XIAP) and Bax. METHODS: Forty-eight female Sprague-Dawley rats (250 ± 50 g) were randomly assigned to one of four groups: ovariectomy with PEMF treatment (PEMF group), ovariectomy with oestradiol (E2) treatment (oestrogen group), ovariectomy control (OVX group) and sham group. The ovariectomy model was prepared by surgical resection of the ovaries. After a three-month intermission, animals in the PEMF and oestrogen groups received treatment for 30 days; then serum 17ß-oestradiol levels, chondrocyte morphology, and XIAP and Bax mRNA expression in knee joint cartilage were analysed. RESULTS: The results showed different chondrocyte formation in each group. Serum E2 content in the PEMF and oestrogen groups was significantly higher than in the OVX group (p < 0.05). The expression of XIAP mRNA in the PEMF and oestrogen groups was significantly up-regulated compared to the OVX group, while that of Bax mRNA was significantly down-regulated (p < 0.05). The correlation between E2 level and expression of Bax mRNA was positive (0.506) and statistically significant (p < 0.001). CONCLUSION: These data demonstrate that PEMF can up-regulate XIAP mRNA expression and down-regulate Bax mRNA expression in ovariectomised rats. Changes in XIAP and Bax mRNA expression may be the mechanism by which PEMF therapy affects postmenopausal osteoarthritis.

Effect of low-level laser therapy on osteoarthropathy in rabbit.

The aim of this study was to determine whether low-level laser therapy (LLLT) aided the recovery of damaged articular cartilage in joints with artificially induced osteoarthropathy (OA). OA was induced by injecting hydrogen peroxide (H2O2) into the articular spaces of both knees in rabbits, twice a week for 4 weeks. The induction of OA and the effect of LLLT were evaluated by biochemical, radiological and histopathological analysis. Superoxide dismutase (SOD) activity increased about 40% in the OA group, as compared to the controls. Although SOD activity in the OA group was not significantly different from the 2-week groups, it was significantly different from the 4-week control and treatment groups. There was also a significant difference between the 4-week control and treatment groups. Simple radiographs and three-dimensional computed tomographs (3D CT) did not show detectable arthropathy in the OA group, nor any particular changes in the 2-week groups. In contrast, distinct erosions were seen in the distal articular cartilage of the femur, with irregularity of the articular surface, in the 4-week control group, while the erosions were reduced and arthropathy improved slightly in the 4-week treatment group. Grossly, erosions formed on the articular surface in the OA group. In comparison, severe erosions damaged the articular cartilage in the 4-week control group, but not in the 2-week control and treatment groups. Regeneration of articular cartilage was seen in gross observations in the 4-week treatment group. Histopathologically, there was slight irregularity of the articular surface and necrosis in the OA group, and serious cartilage damage, despite slight chondrocyte regeneration, in the 4-week control group. Conversely, the 4-week treatment group showed chondrocyte replacement, with sometimes close to normal articular cartilage on the articular surface. These results suggest that LLLT was effective in the treatment of chemically-induced OA.

Dose response of the AIA rabbit stifle joint to boron neutron capture synovectomy.

This study assessed the treatment with boron neutron capture synovectomy of synovitis in the antigen-induced arthritis (AIA) model. A boron compound, potassium dodecahydrododeca-borate (K(2)B(12)H(12)), was injected into stifle joints of 24 AIA and 12 normal rabbits and activated by neutron bombardment of the joint to achieve doses from 800 to 81,000 RBE-cGy. Synovial ablation in the AIA joint was accomplished at doses of 6,000 to 7,000 RBE-cGy with no adverse effects to skin or extracapsular tissues.