Effect of low level laser therapy on articular cartilage and synovium of osteoarthritis & adjuvant arthritis models in rats : Histopathology, electron microscopy & oxidative stress markers assessment

الملخص EN

Objective: Low level laser (LLL) was claimed by some clinicians to have anti-inflammatory and cartilage regenerating effects and was suggested as an alternative non- invasive treatment for rheumatoid arthritis as well as osteoarthritis.

However, its effect on the pathological picture and biochemical parameters of inflammation is still controversial.

Our work aimed at investigating the effect of LLL on two arthritic models: adjuvant arthritis (AA) and osteoarthritis (OA) in rats as models for rheumatoid arthritis (RA) and osteoarthritis (OA) in humans, in an attempt to demonstrate if it has any therapeutic effect on the synovium and cartilage, and to highlight its mechanism in controlling oxidative stress markers which are implicated in the pathogenesis of those diseases.

Methodology: Forty animals were subjected to the study forming 5 groups (normal, AA control, AA laser treated, OA control and OA laser treated).

AA was induced by subcutaneous injection of Freund’s adjuvant, while OA was induced by intraarticular injection of sodium iodoacetate.

Infrared Gal Ars laser (840 n.

meters) was applied in a dose of 5.5 jouls/ cm2 for a power of 60 mW along the joint line every other day.

After treatment for 3 weeks the animals were sacrificed and their knee joints were examined with light and electron microscopes.

Serum nitric oxide (NO), malondialdehyde (MDA) and ceruloplasmin (CP) in addition to blood glutathione (GSH) and erythrocyte superoxide dismutase (SOD) levels/ activities were measured.

Results: Laser has an anti-inflammatory effect on the synovium and on some oxidative stress markers such as malondialdehyde (a parameter for lipid peroxidation) that recommends its use as adjuvant treatment in rheumatoid arthritis.

No significant positive effect was shown on osteoarthritic model as noticed with pathological and biochemical parameters, except for the intact mitochondria in the majority of examined cells with the electron microscope (EM) even if they were undergoing apoptosis.

More studies with different dosage and duration are needed to demonstrate if it has any effect on articular cartilage in OA