Abstract
The therapeutic effect of low-energy He-Ne laser irradiation on rat adjuvant arthritis was evaluated by observing the changes in foot volume and in histology of ankle joints. Five mg/ml of emulsion of Freund's complete adjuvant and tubercle bacilli was given to nine Lewis rats and He-Ne laser irradiation (632.5nm, 8.5mw) was started 4 weeks later. Ten-minute irradiation was given three times a week for 8 weeks on either the right or left foot. A significant decrease in foot volume in the irradiated feet was observed in the first week. The foot volume continuously decreased for 5 weeks, but a significant decrease in the non-irradiated feet was shown only after 6 weeks. The rats were killed at the end of the eighth week and histological changes were compared between the irradiated and the non-irradiated feet. No difference was observed in the bone or cartilage. However, a tendency that the irradiated feet had fewer blood vessels, less cellular infiltrates and stronger fibrosis was found in the synovium.
He-Ne laser irradiation seemed to reduce foot swelling faster and accelerate histological changes. Laser irradiation on a joint may be more effective at an early stage of inflammation.
