ABSTRACT
Objective To investigate the putative relationship between peroxisome proliferators activated receptor gamma (PPARγ) and nuclear factor (NF)-κB in cerulein-treated pancreatic aeinar AR42J cells. Methods The AR42J cells were allocated to control group, pioglitazone group (treated with 40 μmol/L of pioglitazone), pioglitazone + cerulein group (treated with 40 μmol/L of pioglitazone+ 10~(-8) mol/L of cerulein) and pioglitazone + cerulein + PPARγ antagonist (GW9662) group (treated with 40 μmol/L of pioglitazone + 5 μmol/L of GW9662 + 10~(-8) mol/L of cerulein). Activity of NF-κB and PPARγ expression were detected 30 minuts after stimulated by cerulein with or without the presence of pioglitazone. The protein expressions of NF-κB and PPARγ, antibody to IκBα phosphorylation, the differential expression between IκB kinase (IKK)β and IκBa, the IKKβ activity as well as changes of pIκBa were examined by Western blotting. The nuclear accumulation of NF-κB (p65 and p50 subunits) was determined by immunofluorescence and Western blotting. The interaction between NF-κB p65 and IκBα was observed by immunopreeitation. Results Treatment of AR42J cells with pioglitazone attenuated cerulein induced cytosolic activity of IKK protein (1.6 : 3.7)or IκBa phosphorylation (0.9 : 1.5), strengthened the integration of IκBα and NF-κB (0.8:0.3), inhibited transcription activity of p50 and p65 NF-κB dimer and nuclear accumulation (P<0.01). Adversely, the inhibitory effect of pioglitazone on NF-κB activity induced by cerulein was almost reversed by GW9662 (P<0.05). Conclusion These findings provide evidence for the involvement of PPARγ in the activity of NF-κB in cerulein treated AR42J cells.
ABSTRACT
Objective To investigate the effects of pioglitazone,a peroxisome proliferation activated receptor(PPAR)γ agonist on oxidative stress process and the therapeutic effects on severity of acute pancreatitis(AP).Methods Thirty male Sprague-Dawley rats were randomly divided into five groups with 6 in each:control group,eerulein plus pioglitazone group,cerulein group,cerulein plus vehicle group,cerulein plus pioglitazone and GW9662 group.Rats were sacrificed at 30 min after the induction of pancreatitis.Pathologic changes of the pancreas were observed under light microscope.The ratios of pancreatic wet/body weight of rat were determined in each group.Serum amylase,pancreatic nitric oxide synthase(NOS),inducible nitric oxide synthase(iNOS),malondialdehyde(MDA),and myeloperoxidase (MPO)were determined by chromometry.Results The serum amylase,pancreatic wet/body weight and the score of pathologic damage increased after the induction of pancreatitis,AP samples were characterized by increased pancreatic MDA,MPO,NOS and iNOS(P＜0.01).Pioglitazone(20 mg/kg and 40 mg/kg)exhibited a protective effect against oxygen free radicals reflected by lower serum amylase,less severe pancreatic lesions,normal pancreatic MDA,MPO and NOS levels(P＜0.05).GW9662 reversed the effects against oxidative stress of pioglitazone(40 mg/kg)(P＜0.05).Conclusions Pretreatment with pioglitazone may exert its therapeutic effect on AP by lowering pancreatic oxidative free radicals and reducing pancreatic tissue infiltration of neutrophils.