RESUMO
BACKGROUND/AIMS: To investigate the expression of Toll-like receptor 4 (TLR4) in the pancreases of rats with acute necrotizing pancreatitis (ANP) and any changes upon treatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor kappaB (NF-kappaB), as well as to determine the relationship between TLR4 and NF-kappaB in ANP pathogenesis. METHODS: A total of 72 SD rats were randomly divided into three groups, namely, the control (sham-operation), ANP, and ANP with PDTC pretreatment groups. The PDTC-pretreated group was intraperitoneally injected with PDTC at a dose of 100 mg/kg 1 hour before the induction of ANP. The expressions of TLR4 and NF-kappaB in pancreatic tissue were evaluated by immunohistochemistry and Western blot analysis. The mRNA levels of cytokines tumor necrosis factor alpha, interleukin (IL)-1beta, and IL-6 were measured by reverse transcription polymerase chain reaction. RESULTS: The expressions of TLR4, NF-kappaB, and cytokine (NF-kappaB target) genes in the pancreatic tissue increased more significantly in the ANP groups than in the sham-operation group at 3, 6, and 12 hours. Pretreatment with PDTC alleviated the inflammatory activation in the pancreas with ANP, causing a significant decrease in the expressions of TLR4, NF-kappaB, and cytokine genes in the pancreatic tissue. CONCLUSIONS: The expressions of TLR4 and NF-kappaB were increased in the pancreases of rats with ANP. PDTC not only inhibits NF-kappaB but also suppresses the expression of TLR4 and downregulates the expression of the related cytokine genes.
Assuntos
Animais , Masculino , Ratos , Antioxidantes/farmacologia , Interleucina-1beta/genética , Interleucina-6/genética , NF-kappa B/efeitos dos fármacos , Pâncreas/metabolismo , Pancreatite Necrosante Aguda/induzido quimicamente , Pirrolidinas/farmacologia , RNA Mensageiro/metabolismo , Distribuição Aleatória , Ratos Sprague-Dawley , Tiocarbamatos/farmacologia , Receptor 4 Toll-Like/efeitos dos fármacos , Fator de Necrose Tumoral alfa/genéticaRESUMO
BACKGROUND/AIMS: To investigate the expression of Toll-like receptor 4 (TLR4) in the pancreases of rats with acute necrotizing pancreatitis (ANP) and any changes upon treatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor kappaB (NF-kappaB), as well as to determine the relationship between TLR4 and NF-kappaB in ANP pathogenesis. METHODS: A total of 72 SD rats were randomly divided into three groups, namely, the control (sham-operation), ANP, and ANP with PDTC pretreatment groups. The PDTC-pretreated group was intraperitoneally injected with PDTC at a dose of 100 mg/kg 1 hour before the induction of ANP. The expressions of TLR4 and NF-kappaB in pancreatic tissue were evaluated by immunohistochemistry and Western blot analysis. The mRNA levels of cytokines tumor necrosis factor alpha, interleukin (IL)-1beta, and IL-6 were measured by reverse transcription polymerase chain reaction. RESULTS: The expressions of TLR4, NF-kappaB, and cytokine (NF-kappaB target) genes in the pancreatic tissue increased more significantly in the ANP groups than in the sham-operation group at 3, 6, and 12 hours. Pretreatment with PDTC alleviated the inflammatory activation in the pancreas with ANP, causing a significant decrease in the expressions of TLR4, NF-kappaB, and cytokine genes in the pancreatic tissue. CONCLUSIONS: The expressions of TLR4 and NF-kappaB were increased in the pancreases of rats with ANP. PDTC not only inhibits NF-kappaB but also suppresses the expression of TLR4 and downregulates the expression of the related cytokine genes.
Assuntos
Animais , Masculino , Ratos , Antioxidantes/farmacologia , Interleucina-1beta/genética , Interleucina-6/genética , NF-kappa B/efeitos dos fármacos , Pâncreas/metabolismo , Pancreatite Necrosante Aguda/induzido quimicamente , Pirrolidinas/farmacologia , RNA Mensageiro/metabolismo , Distribuição Aleatória , Ratos Sprague-Dawley , Tiocarbamatos/farmacologia , Receptor 4 Toll-Like/efeitos dos fármacos , Fator de Necrose Tumoral alfa/genéticaRESUMO
Porcine reproductive and respiratory syndrome virus (PRRSV) non-structural protein 7 (Nsp7) plays an important role in the induction of host humoral immune response and could serve as an ideal antigen for serological genotyping assay for PRRSV based on the significant difference in immunoreactivities of North American (NA) and European (EU) PRRSV Nsp7. In this study, Nsp7 of NA and EU PRRSVwas separately expressed and purified using prokaryotic expression system. The purified recombinant Nsp7 proteins reacted with serum antibodies against corresponding genotype PRRSV in Western blotting. However, nonspecific reaction of whole recombinant Nsp7 with antibodies against another genotype PRRSV was observed, indicating that whole NA PRRSV Nsp7 and EU PRRSV Nsp7 have similar antigenic epitopes and recombinant proteins could not be used for genotyping of antibodies against PRRSV. Based on the analysis of similar antigenic epitopes at the hydrophilic region of NA PRRSV Nsp7 and EU PRRSV Nsp7 by bioinformatics assessment, partial Nsp7 gene region deleted sequences encoding similar antigenic epitopes was constructed by fusion PCR. The recombinant truncated Nsp7 (NA-deltaNsp7 and EU-deltaNsp7, about 43 kDa) was expressed and the molecular weight was about 43 kDa. The results of Western blotting showed that NA-deltaNSP7 and EU-deltaNSP7 could be specifically recognized by positive serum to NA or EU PRRSV individually and nonspecific reaction was eliminated. This study provided a basis for further development of serological genotyping assay for North American and European genotype PRRSV infection.