Prostaglandin E2 in Experimental Arthritis of Rats Irradiated with He-Ne Laser

Abstract
The objective of this work was to investigate the effect of He-Ne laser radiation on the synthesis of PGE2 in rats with experimental arthritis induced by hydroxyapatite. Ten white rats of 280–320 g body weight were injected in both leg joints with 3 mg hydroxyapatite in saline. The left leg joints were immediately irradiated with He-Ne laser (8 J/cm2) and the irradiation was repeated at 24-hr periods, three times. The right legs joints were used as control. After 96 hr the animals were sacrificed and a pool was formed with the injected and nonradiated joints of each animal. PGE2 was quantified on the incubation medium by RIA. In the injected and nonradiated animals the level of PGE2 was 310.2 ± 42.4 ng/mg of dry tissue/60 min, while the irradiated ones showed a level of 163.9 ± 22.3 ng/mg dry tissue/60 minutes with a statistically significant difference (p < 0.02). These results indicate that He-Ne laser radiation reduces the synthesis of PGE2 in arthritis.