Study type: Therapeutical study (experimental study)

The effect of local deep microwave hyperthermia on experimental zymosan-induced arthritis in rabbits. med. app.

Published in: Am J Phys Med Rehabil 1990; 69 (5): 239-244

Aim of study (acc. to author)

To evaluate the effect of local deep microwave hyperthermia on normal and Zymosan-induced arthritis in rabbits.



Exposure Parameters
Exposure 1: 915 MHz
Exposure duration: 60 min, 2 times per week for 2 weeks

Exposure 1

Main characteristics
Frequency 915 MHz
Exposure duration 60 min, 2 times per week for 2 weeks
Exposure setup
Exposure source
Setup Cylindrical tube attached to the lateral aspect of the left hind joint of the rabbits. The applicator was positioned in such a way that the electromagnetic radiation was aimed towards the joint, with maximum radiation near the joint cavity.
Additional info Water (20°C) flowed on the surface of the applicator cooled the skin adjacent to the applicator at the knee joint area. The intraarticular temperature was maintained at 42.5 ± 0.5°C. The right knee was not heated and served as control.
Measurand Value Type Method Mass Remarks
power 15 W maximum measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
  • knee
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

The application of local deep microwave hyperthermia on normal joints induced a limited proliferation of the synovial lining cells. However, no histologic damage to the skin, muscles, bone, cartilage or bone marrow adjacent to the heated joints could be found. Induction of Zymosan arthritis was characterized by pannus formation and granulomatous reaction. The local deep microwave hyperthermia application on the examined arthritic joints brought about a reduction in the degree of granulomatous reaction concomitant with the appearance of some fibrocytes and fine collagen fibrils.
These results suggest that local deep microwave hyperthermia can be safely applied without morphologic evidence of damage to any normal mesenchymal tissue. Moreover, it reduces the inflammatory process in experimentally induced synovitis.

Study character:

Study funded by