Modulation of lipopolysaccharide-induced oxidative stress by capsaicin

This study investigated the effect of capsaicin (the active principle of hot red pepper and a sensory excitotoxin) on oxidative stress after systemic administration of the endotoxin lipopolysaccharide (100 lg/kg, i.p.) in rats. Capsaicin (15, 150 or 1,500 lg/kg; 10, 100 or 400 lg/ mL) was given via intragastric (i.g.) or intraperitoneal (i.p.) routes at time of endotoxin administration. Rats were killed 4 h later. Malondialdehyde (MDA) and reduced glutathione (GSH) were measured in brain, liver, and lungs. Alanine aminotransferase (ALT), aspartate aminotransferase, alkaline phosphatase (ALP), nitric oxide, and glucose were measured in serum. In addition, histopathological examination of liver tissue was performed. In LPS-treated rats, hepatic GSH increased significantly by 40.8% after i.p. capsaicin at 1,500 lg/kg. Liver MDA increased significantly by 32.9% after the administration of i.g. capsaicin at 1,500 lg/kg and by 27.8 and 37.6% after the administration of i.p. capsaicin at 150 and 1,500 lg/kg, respectively. In lung tissue, both MDA and GSH were decreased by capsaicin administration. MDA decreased by 19-20.8% after i.g. capsaicin and by 17.5-23.2% after i.p. capsaicin (150-1,500 lg/kg), respectively. GSH decreased by 39.3-64.3% and by 35.7-41.1% after i.g. or i.p. capsaicin (150-1,500 lg/kg), respectively. Brain GSH increased significantly after the highest dose of i.g. or i.p. capsaicin (by 20.6 and 15.9%, respectively). The increase in serum ALT and ALP after endotoxin administration was decreased by oral or i.p. capsaicin. Serum nitric oxide showed marked increase after LPS injection, but was markedly decreased after capsaicin (1,500 lg/kg, i.p.). Serum glucose increased markedly after the administration of LPS, and was normalized by capsaicin treatment. It is suggested that in the presence of mild systemic inflammation, acute capsaicin administration might alter oxidative status in some tissues and exert an anti-inflammatory effect. Capsaicin exerted protective effects in the liver and lung against the LPS-induced tissue damage. © Springer Basel AG 2011.