Anti-inflammatory and anti-necrotic effects of lectins from Canavalia ensiformis and Canavalia brasiliensis in experimental acute pancreatitis.

Lectins isolated from Canavalia ensiformis (ConA) and Canavalia brasiliensis (ConBr) are promising molecules to prevent cell death. Acute pancreatitis, characterized by acinar cell necrosis and inflammation, presents significant morbidity and mortality. This study has investigated the effects of ConA and ConBr in experimental acute pancreatitis and pancreatic acinar cell death induced by bile acid. Pancreatitis was induced by retrograde pancreatic ductal injection of 3% sodium taurocholate (Na-TC) in male Swiss mice. ConA or ConBr (0.1, 1 or 10 mg/kg) were intravenously applied to mice 1 h and 12 h after induction. After 24 h, the severity of pancreatitis was evaluated by serum amylase and lipase, histopathological changes and myeloperoxidase assay. Pancreatic acinar cells were incubated with ConA (200 µg/ml) or ConBr (200 µg/ml) and taurolithocholic acid 3-sulfate (TLCS; 500 µM). Necrosis and changes in mitochondrial membrane potential (ΔÑ°m) were detected by fluorescence confocal microscopy. Treatment (post-insult) with ConA and ConBr decreased pancreatic damage caused by retrograde injection of Na-TC in mice, reducing pancreatic neutrophil infiltration, edema and necrosis. In addition, ConA and ConBr decreased pancreatic acinar cell necrosis and depolarization of ΔÑ°m caused by TLCS. The inhibition of necrosis was prevented by the lectin domain blockade. In conclusion, ConA and ConBr markedly inhibited in vitro and in vivo damage, effects partly dependent on the interaction with mannose residues on acinar cells. These data support the potential application of these proteins for treatment of acute pancreatitis.

Sulfated polysaccharide from Gracilaria caudata reduces hypernociception and inflammatory response during arthritis in rodents.

Polysaccharide from marine alga Gracilaria caudata has potential health benefits, such as anti-inflammatory, gastroprotective and antidiarrheal effects. Here, we investigated the effect of a sulfated polysaccharide from G. caudata (SP-GC) on hypernociception and inflammatory response in arthritis models. The animals received SP-GC (3, 10 or 30 mg/kg) 1 h before tibio-tarsal injection of zymosan. Hypernociception, histopathology, edema, vascular permeability, myeloperoxidase (MPO) activity, cell influx, interleukin (IL)-1ß and nitric oxide (NO) levels were evaluated in acute phase. In another protocol, animals received SP-GC (30 mg/kg) 2 h post-complete Freund's adjuvant (CFA). Hypernociception, edema and arthritis index were determined in acute, sub-chronic and chronic phases. Rota-rod test measured the motor performance. SP-GC significantly reduced, in a dose-dependent manner, the zymosan-induced hypernociception with maximal effect at 30 mg/kg. The microscopic inflammation, joint edema, MPO activity, cell influx, IL-1ß and NO levels were also reduced by SP-GC. In the CFA-induced arthritis, SP-GC inhibits the hypernociception, edema and arthritic index in acute, sub-chronic and chronic phases. SP-GC did not alter the motor performance of animals. In conclusion, SP-GC exerts protective effect in models of arthritis due to the modulation of cell influx, IL-1ß and NO levels, culminating in the reduction of hypernociception and edema.