Suppression of inducible nitric oxide synthase and tumor necrosis factor-alpha level by lycopene is comparable to methylprednisolone in acute pancreatitis

Oxidative stress and inflammation may play a key role in the pathogenesis of acute pancreatitis (AP). Lycopene, a natural carotenoid, has antioxidant scavenger capacity and inhibits inflammation in many experimental models. The study was designed to investigate whether lycopene can ameliorate l-arginine-induced pancreatitis in rats and to elucidate the underlying molecular mechanisms of these effects. Forty-eight adult male Wistar rats were divided into: control group (vehicle, orally, 10 days), AP group (3 g/kg l-arginine, single i.p. injection, on day 10th of the experiment), lycopene group (50 mg/kg) and methylprednisolone group (30 mg/kg). Lycopene and methylprednisolone were given orally, once daily for 10 days prior to l-arginine injection. Rats were sacrificed 24 h after l-arginine injection. Inflammation/oxidative stress and pancreatic markers were assessed. Pancreatic histopathological studies were done. Lycopene group showed a significant reduction in tumor necrosis factor alpha (TNF-α), myeloperoxidase activity, and down-regulation of inducible nitric oxide synthase (iNOS) gene expression. Pancreatic nitric oxide concentration was reduced and pancreatic GSH was increased in lycopene group. Serum α-amylase and lipase activities were reduced by lycopene treatment. The histology of pancreas was improved in lycopene group as well as methylprednisolone group. Lycopene prior treatment proved anti-inflammatory and antioxidant effects against AP rat model via different mechanisms.