Nitric oxide (NO) is known to be both helpful and harmful in our bodies. Nitric oxide is produced from enzymes called nitric oxide synthases. There are several types of these enzymes. One of the isoenzymes is called constitutive nitric oxide synthase (cNOS). It is felt that cNOS is decreased in joints with osteoarthritis. Harmful nitric oxide is produced by an isoenzyme called inducible nitric oxide synthase (iNOS). As a response to trauma or wear and tear, iNOS may be increased.
The pain of osteoarthritis tends to lead to loss of movement, disability, decreased quality of life, and can be costly. Many pain-relieving medications have significant side effects or are not very effective for analgesia. Several non-pharmacological modalities have been shown to reduce pain in osteoarthritis. The authors propose that the use of monochromatic infrared photo energy (MIRE) can be a useful physical therapy treatment for osteoarthritis. Pain relief is a goal, as well as improvement or reversal of the osteoarthritis pathology. MIRE is believed to increase the production of NO in joints by the cNOS pathway.
The authors of the study propose that the use of MIRE produces energy at an 890 nm wavelength, applied at the skin surface can be absorbed in to blood vessels. Treatment involves the placement of pads containing 60 near-infrared diodes over the joint for 30 minutes. The authors propose that blood flow can be increased, inflammation can be decreased, and nerve excitability may be decreased by NO produced from cNOS after treatment with MIRE. They propose that chemical changes after treatment with MIRE can increase blood flow for as long as three hours.
Case studies have shown that treatment of knee osteoarthritis with MIRE can decrease pain, improve quality of life, and had no detrimental side effects. The authors also feel that MIRE may improve the underlying osteoarthritis pathology. Controlled clinical studies have not been conducted on the use of MIRE however.