ABSTRACT
PURPOSE: Because previous studies have reported depleted antioxidant capacity in patients with chronic pancreatitis (CP), prevention of free radical production has gained importance in antifibrotic treatment strategies for CP. The aim of this study was to investigate the effects of ascorbic acid on oxidative capacity and pancreatic damage in experimental CP. MATERIALS AND METHODS: CP was induced in male Sprague-Dawley rats by infusion of dibutyltin dichloride (DBTC) into the tail vein. Ascorbic acid was given intraperitoneally at a daily dose of 10mg/kg body weight. The treatment groups were as follows: group 1, DBTC plus intraperitoneal physiologic saline; group 2, DBTC plus intraperitoneal ascorbic acid; group 3, solvent plus intraperitoneal physiologic saline; group 4, no operation plus intraperitoneal physiologic saline. Each group contained 15 animals. Treatment was started after CP was established. After 4 weeks of treatment, serum hyaluronic acid and laminin levels were determined by radioimmunoassay, pancreatic tissue oxidative stress was analyzed, and the degree of pancreatic damage was determined. RESULTS: Ascorbic acid treatment markedly increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) concentrations in pancreatic tissue (p < 0.01 for both). Significant serum hyaluronic acid and laminin reductions were observed in group 2 as compared with group 1 (p < 0.05). However, the serum hyaluronic acid and laminin levels remained elevated when compared with those of groups 3 and 4 (p < 0.05). Histopathologic scores were also lower in animals with CP that underwent ascorbic acid-treatment (p < 0.05). CONCLUSION: Ascorbic acid treatment alleviated the degree of oxidative stress and pancreatic damage in rat CP. Antioxidant treatment might be considered a potential option to improve the pathologic process in CP.
Subject(s)
Animals , Male , Rats , Antioxidants/pharmacology , Ascorbic Acid/pharmacology , Hyaluronic Acid/blood , Laminin/blood , Organotin Compounds , Oxidative Stress/drug effects , Pancreas/drug effects , Pancreatic Diseases/blood , Rats, Sprague-DawleyABSTRACT
<p><b>BACKGROUND</b>China is one of the countries with the highest incidence of H. pylori and more than 9090 isolates possessed the cagA gene. This study was to evaluate the biological activity of the H. pylori virulence factor cagA isolated from Chinese patients.</p><p><b>METHODS</b>cagA DNA fragments were amplified from the genomic DNA and subsequently cloned into the mammalian expression vector for cell transfection and DNA sequencing. cagA protein, phosphorylated-tyrosine cagA and the complex of cagA precipitated with SHP-2 were identified respectively by western blot in the crude cell lysate from conditionally immortalized gastric epithelial cells at 48 hours after transfection with cagA DNA. In addition, the ability of induction of scattering phenotype was examined after transient expression of cagA in AGS cells.</p><p><b>RESULTS</b>The C-terminal half of cagA contained only one repeated sequence and three tandem five-amino-acid motifs glutamic acid-proline-isoleucine-tyrosine-alanine (EPIYA). Moreover, the amino acid sequence of D2 region in repeated sequence was aspartic acid-phenylanaline-aspartic acid (D-F-D) which was significantly distinguished from the three repeated sequences and aspartic acid-aspartic adid-leucine (D-D-L) in the western standard strain NCTC11637. Western blot revealed that cagA became phosphorylated in tyrosine site and bound with SHP-2 after transient expression of cagA DNA in gastric epithelial cells. Transient expression of cagA in AGS cells showed that cagA was able to induce the elongation phenotype although to a lesser extent than western strains.</p><p><b>CONCLUSIONS</b>cagA perturbs cell signaling pathways by binding with SHP-2. However, significant difference exists in amino acid sequence and biological function of cagA in Chinese compared with those of western countries.</p>
Subject(s)
Humans , Amino Acid Sequence , Antigens, Bacterial , Chemistry , Physiology , Bacterial Proteins , Chemistry , Physiology , Blotting, Western , Cells, Cultured , Gastric Mucosa , Intracellular Signaling Peptides and Proteins , Molecular Sequence Data , Phenotype , Phosphorylation , Protein Tyrosine Phosphatase, Non-Receptor Type 11 , Protein Tyrosine Phosphatases , Metabolism , Repetitive Sequences, Amino Acid , Signal TransductionABSTRACT
<p><b>OBJECTIVE</b>To investigate the plasma levels of ascorbic acid and vitamin E in patients with liver cirrhosis and to explore their significance.</p><p><b>METHODS</b>The plasma levels of ascorbic acid,vitamin E and lipoperoxides in patients with liver cirrhosis were measured, and the results were compared with those of sex-and age-matched healthy subjects.</p><p><b>RESULT</b>The plasma levels of ascorbic acid, vitamin E and lipoperoxides in the patients group were (42.94 +/-6.99)micromol/L, (17.99 +/-3.51)micromol/L and (14.09 +/-1.28)micromol/L, respectively, while those in the control group were (53.30 +/-9.45)micromol/L (t=9.50, P=0.000), (24.59 +/-7.22)micromol/L (t=7.94, P=0.000) and (12.11 +/-1.20)micromol/L (t=17.21, P=0.000), respectively.</p><p><b>CONCLUSION</b>The levels of ascorbic acid and vitamin E in patients with liver cirrhosis decrease significantly,which may indicates the disturbance of balance between oxidation and antioxidation.</p>