The Lectin Isolated from the Alga Hypnea cervicornis Promotes Antinociception in Rats Subjected to Zymosan-Induced Arthritis: Involvement of cGMP Signalization and Cytokine Expression.

Abstract

This study investigated the effects of the alga lectin Hypnea cervicornis agglutinin (HCA) on rat zymosan-induced arthritis (ZyA). Zymosan (50-500μg/25μL) or sterile saline (Sham) was injected into the tibio-tarsal joint of female Wistar rats (180-200g). Arthritic animals received morphine (4mg/kg, intraperitoneal), indomethacin (5mg/kg, intraperitoneal), or 2% lidocaine (100μL, subcutaneous). HCA (0.3-3mg/kg) was administered by intravenous route 30min before or 2h after zymosan. 1H-[1,2,4]oxadiazolo[4,3-a]-quinoxalin-1-one (ODQ, 4μg, intra-articular) was given 30min prior HCA. Hypernociception was measured every hour until 6h, time in which animals were sacrificed for evaluation of leukocytes of the intra articular fluid and gene expression of TNF-α, IL-1, IL-10, and iNOS in the joint tissues using PCR techniques. Hypernociception was responsive to morphine and indomethacin, and its threshold was not altered by lidocaine. The post-treatment of HCA reduced both hypernociception and leukocyte influx. This antinociceptive effect was abolished either by ODQ and glibenclamide. HCA also reduced gene expression of iNOS and TNF-α. In conclusion, the antinociceptive effect of HCA in ZyA involves cyclic GMP signalization and selective modulation of cytokine expression.