leukotriene-b4 and Cholestasis

We tested the hypothesis that leukotriene B4 (LTB4) mediates pancreatic inflammation in rats via activation of the transient receptor potential vanilloid 1 (TRPV1).. Leukotriene B4 or a vehicle was administered to adult rats via celiac axis injection after pretreatment with the TRPV1 antagonist, capsazepine, or vehicle, and the severity of subsequent pancreatitis was assessed by measuring pancreatic edema, myeloperoxidase (MPO) activity, and histological grading. In a second experiment, acute pancreatitis was induced by common pancreaticobiliary duct ligation. Six hours after surgery, pancreatic tissue levels of LTB4 were determined by enzyme-linked immunosorbent assay. Also, the effects of inhibition of LTB4 biosynthesis by pretreatment with the 5-lipoxygenase-activating peptide inhibitor, MK-886, were determined.. Celiac axis administration of LTB4 significantly increased pancreatic edema and MPO activity, and produced histological evidence of pancreatic edema, neutrophil infiltration, and necrosis. Capsazepine pretreatment significantly reduced all inflammatory parameters in LTB4-induced pancreatitis. Pancreatic tissue levels of LTB4 were significantly elevated in rats that underwent common pancreaticobiliary duct ligation compared with control rats. MK-886 pretreatment significantly inhibited pancreatic edema, histological damage, and pancreatic MPO concentrations.. Common pancreaticobiliary duct obstruction causes an increase in pancreatic LTB4 concentrations that in turn mediates activation of TRPV1 resulting in acute pancreatitis.

Topics: Animals; Capsaicin; Cholestasis; Disease Models, Animal; Indoles; Inflammation Mediators; Leukotriene B4; Ligation; Lipoxygenase Inhibitors; Male; Models, Biological; Pancreatitis; Peroxidase; Rats; Rats, Sprague-Dawley; TRPV Cation Channels

The role of leukotriene (LT) on liver regeneration after hepatectomy is still unknown. LTB4 stagnates in the liver with obstructive jaundice, because LTB4 is excreted in the bile; therefore, LTB4 may have an effect on liver regeneration after hepatectomy with obstructive jaundice. Release of obstructive jaundice and simultaneous 70% hepatectomy was performed in rats to study the effect of 5-lipoxygenase inhibitor (AA-861) on liver regeneration. Group 1 underwent hepatectomy with administration of 0.1 mL dimethyl sulfoxide (DMSO), group 2 underwent hepatectomy with administration of AA-861 (20 mg/kg/d) dissolved in 0.1 mL DMSO, group 3 underwent hepatectomy with administration of AA-861 (40 mg/kg/d) dissolved in 0.1 mL DMSO, group 4 underwent release of obstructive jaundice and hepatectomy with administration of 0.1 mL DMSO, and group 5 underwent relief of obstructive jaundice and hepatectomy with administration of AA-861 (20 mg/kg/d). DMSO or AA-861 was administered 24 hours before, during, and 24 hours after hepatectomy in each group. Whole blood LTB4 and serum alanine aminotransferase (ALT), total bilirubin, and bromodeoxyuridine labeling index (LI) were measured before and after hepatectomy. The LTB4 level increased during obstructive jaundice and after hepatectomy. LTB4 and serum ALT levels were significantly lower after hepatectomy in the rats that were administered AA-861, and a significantly higher LI was observed at 24 hours after hepatectomy in rats receiving AA-861. Inhibition of 5-lipoxygenase promotes liver regeneration and decreases hepatocyte injury after hepatectomy associated with obstructive jaundice.

Topics: Alanine Transaminase; Animals; Benzoquinones; Bilirubin; Bromodeoxyuridine; Cholestasis; Hepatectomy; Leukotriene B4; Lipoxygenase Inhibitors; Liver Regeneration; Male; Rats; Rats, Wistar