Changes in superoxide dismutase activity and peroxynitrite content in rat peritoneal macrophages exposed to He-Ne laser radiation.

The formation of reactive oxygen and nitrogen species by rat peritoneal macrophages induced by a low-intensity He-Ne laser radiation (LR) was studied in this work. It was found that the formation of reactive oxygen species, nitric oxide, and peroxynitrite as well as changes in the activity of superoxide dismutase (SOD) depended to a large extent on the LR dose. In particular, it was found that activation of SOD at low LR doses was accompanied by nitric oxide level increase, while the level of peroxynitrite showed no significant changes. On the other hand, an enhanced LR dose inhibited the enzyme, and this was accompanied by peroxynitrite accumulation. All the measurements were carried out the day after LR treatment. The revealed regularities consequently demonstrate the existence of a deferred LR action on macrophages associated with the production of reactive oxygen and nitrogen species.

[Effect of low intensity laser light in the red range on macrophage superoxide dismutase activity]. / Vliianie nizkointensivnogo lazernogo izlucheniia krasnogo diapazona na aktivnost' superoksiddismutazy makrofagov.

The effect of lipopolysaccharides (LPS) and low-power laser radiation on nitric oxide (NO) production and the activity of superoxide dismutase (SOD) in rat peritoneal exudate macrophages was investigated. It was found that LPS increased NO production and SOD activity in macrophages in a concentration-dependent manner. The maximal activity of SOD was more than 100 times greater than in the control and was achieved at an LPS concentration of less than 10 ng/ml. The maximal production of NO was more than 250% of the control and was achieved at an LPS concentration of 100 ng/ml. The presence of cycloheximide, a transcriptional synthesis inhibitor, in conditioned media almost completely abolished SOD activation and NO production. This implies that the LPS-induced increase in SOD activity and NO production were determined by the activation of de novo protein synthesis (SOD and inducible NO synthase). The irradiation of macrophages by red light resulted in a dose-dependent increase in NO production and SOD activity. The incubation of irradiated cells in the presence of 10 microM cycloheximide abolished the increase. The presence of antioxidants (mexidol and ascorbate) also significantly inhibited the laser-induced activity of macrophages. Thus, laser irradiation of cells in the red range activates the synthesis of SOD and inducible NO-synthase de novo due to photosensitized initiation of free radical reactions.

Mechanism of therapeutic effect of low-intensity infrared laser radiation.

The effect of infrared low-intensity laser irradiation on functional activity of blood polymorphonuclear leukocytes was studied in vitro. A dose-dependent priming of polymorphonuclear leukocytes induced by infrared low-intensity laser irradiation was demonstrated. Similar effects were also observed in the presence of the photosensitizer photosense.