Optimization of pulsed electromagnetic field therapy for management of arthritis in rats

Abstract

Studies were undertaken to find out the effects of low frequency pulsed electromagnetic field (PEMF) in adjuvant induced arthritis (AIA) in rats, a widely used model for screening potential therapies for rheumatoid arthritis (RA). AIA was induced by an intradermal injection of a suspension of heat killed Mycobacterium tuberculosis (500 mug/0.1 ml) into the right hind paw of male Wistar rats. This resulted in swelling, loss of body weight, increase in paw volume as well as the activity of lysosomal enzymes viz., acid phosphatase, cathepsin D, and beta-glucuronidase and significant radiological and histological changes. PEMF therapy for arthritis involved optimization of three significant factors, viz., frequency, intensity, and duration; and the waveform used is sinusoidal. The use of factorial design in lieu of conventional method resulted in the development of an ideal combination of these factors. PEMF was applied using a Fransleau-Braunbeck coil system. A magnetic field of 5 Hz x 4 muT x 90 min was found to be optimal in lowering the paw edema volume and decreasing the activity of lysosomal enzymes. Soft tissue swelling was shown to be reduced as evidenced by radiology. Histological studies confirmed reduction in inflammatory cells infiltration, hyperplasia, and hypertrophy of cells lining synovial membrane. PEMF was also shown to have a membrane stabilizing action by significantly inhibiting the rate of release of beta-glucuronidase from lysosomal rich and sub-cellular fractions. The results indicated that PEMF could be developed as a potential therapy in the treatment of arthritis in humans.

Attenuation of adjuvant-induced arthritis by dietary sesamol via modulation of inflammatory mediators, extracellular matrix degrading enzymes and antioxidant status

“…Similarly, ALP is a membranebound protein whose activity directly corresponds to the degree of inflammation in PMN. The present results are in tune with the previous reports that demonstrated the augmented levels of ALP, ACP and TRAP [33].…”

Low frequency and low intensity pulsed electromagnetic field exerts its antiinflammatory effect through restoration of plasma membrane calcium ATPase activity

“…It has been reported that PEMF affects membrane mediated signal transduction processes, especially the Ca 2+ transport system (Yost and Liburdy, 1992). Earlier studies have shown that PEMF has significant antiinflammatory effect in adjuvant induced arthritis in rats (Poornapriya et al, 1998, Senthil Kumar et al, 2005. The present study is undertaken to investigate the possible mechanism of action by which PEMF exerts its protective effect in adjuvant induced arthritis (AIA).…”

“…The rats were exposed to PEMF at 5 Hz × 4 μT × 90 min (Senthil Kumar et al, 2005) from day 14 to day 56 after induction of arthritis. Diclofenac sodium at a dose of 1 mg/kg body weight (per oral, P.O) was given from day 14 to day 56, which served as positive control.…”

The use of magnetic fields in treatment of patients with rheumatoid arthritis. Review of the literature

“…The aim of the research carried out by Kumar et al [41] was to evaluate the effect of pulsed electromagnetic fields (PEMF) on experimentally induced inflammation in rats. A sinusoidal unipolar magnetic field was applied with different parameters.…”

“…The activity of lysosomal enzymes, inflammatory cell infiltration as well as swelling were assessed. Optimal field parameters were 4 mT, 5 Hz and exposure time of 90 min in that case [41]. In studies by Dortch and Johnson [42] rats with experimentally induced rheumatoid arthritis were subjected daily to AC magnetic field with the parameters 10 mT and 5–50 Hz.…”