Salmon cartilage proteoglycan attenuates allergic responses in mouse model of papain‑induced respiratory inflammation.

Proteoglycan (PG) is a complex glycohydrate, which is widely distributed in the extracellular matrix. It has been reported that daily oral administration of PG (extracted from salmon nasal cartilage) modulates the severity of proinflammatory cytokine responses in mouse experimental colitis, autoimmune encephalomyelitis, collagen‑induced arthritis and obesity‑induced inflammation. The present study investigated the effect of salmon nasal cartilage PG on allergic responses using a mouse model of papain‑induced respiratory inflammation. Low titers of immunoglobulin E were identified in the sera of the PG‑administered mice. Oral administration of PG attenuated eosinophil infiltration in the lung. In the acute model of papain‑induced allergic inflammation, PG‑administered mice exhibited low titers of epithelium‑derived and T helper 2‑associated cytokines. The results of the present study demonstrated that salmon cartilage PG has an immunomodulatory effect on intranasally delivered papain. These results suggest a potential role for PG as a prophylactic agent which may attenuate allergic respiratory inflammation.