The Efficacy of Spirulina in Comparison with Methotrexate in the Treatment of Induced Monoarthritis in Rats

Abstract

The incidence of degenerative and inflammatory joint diseases, namely osteoarthritis and rheumatoid arthritis, is very high over the world. Rheumatoid arthritis is an immune-based chronic inflammatory synovitis presenting with pain, stiffness and swelling of the affected joints. It results in secondary bone and cartilage destruction causing joint deformity. Methotrexate is used in treatment of many diseases such as cancer and autoimmune diseases. Because of its effectiveness, low-dose methotrexate is now first-line therapy for the treatment of rheumatoid arthritis. Though methotrexate for autoimmune diseases is taken in lower doses than it is for cancer, side effects such as hair loss, nausea, headaches, and skin pigmentation are still common.Spirulina is a human and animal food or nutritional supplement contains high protein content by dry weight. It is a complete protein containing all essential amino acids. In human research, spirulina was found to reduce the inflammation involved in arthritis in geriatric patients. The goal of this research was to compare between the efficacy of spiulina and methotrexate in the treatment of induced monoarthritis in rats. Forty-eight adult male rats were used in the study and were divided into six groups. Groups 1, 2, and 3 served as control, methotrexate, and spirulinagroups respectively. Rats in group 4 were used as a model of induced arthritis with a single injection of Freund’s complete adjuvant into the right knee joints and were subdivided into 2 subgroups, rats in subgroup 4-a were left untreated and sacrificed on the 4th day after induction of arthritis, while rats in subgroup 4-b were left untreated and sacrificed after 45 days. Rats in group 5 and group 6 were subjected first to arthritis induction using the same drug as group 4, and after four days, they were subjected to methotrexate treatment in the oral dose of 0.3mg. / kg. b.w. twice weekly till the 45thday of the experiment for group 5, and to spirulina treatment in the daily oral dose of 400mg. / kg b.w. till the45thday of the experiment for group 6, then rats were sacrificed. Knee joints were dissected out and processed for gross, radiological, and microscopic examinations. Gross and microscopic inflammatory changes of arthritic joints were evident on the 4th day after induction of arthritis in subgroup 4-a. These changes worsened and were accompanied by degenerative changes in the articular cartilage after 45 days in subgroup 4-b. These degenerative changes were in the form of decreased thickness of the non-calcified cartilage, disorganization with increased number of apoptotic chondrocytes especially in the area close to the articular surface. Fissures and surface erosions were also noted. Furthermore, the cartilage matrix showed a decrease in proteoglycans staining intensity, suggesting its depletion. Spirulina and methotrexate treatment efficientlyreversed most of these degenerative changes.Arthritic groups treated with spirulina and methotrexate showed nearly normal thickness and organization of the articular cartilage. The cartilage matrix showed nearly normal staining affinity, denoting its good proteoglycans content. Moreover, the normal distribution of the collagenfibers was nearly restored. It is concluded that spirulina was nearly as effective as methotrexate in managing the articular cartilage structural damages after adjuvant-induced arthritis in rat knee joints.