The Effects of Lycium Barbarum Polysaccharide (LBP) in a Mouse Model of Cerulein-Induced Acute Pancreatitis.

BACKGROUND Acute pancreatitis is an inflammatory disease of the pancreas associated with high patient morbidity. Lycium barbarum polysaccharide (LBP), a traditional Chinese medicine with an active component extracted from the goji berry, has previously been reported to have anti-inflammatory effects. This study aimed to investigate the effects of LBP in a mouse model of cerulein-induced acute pancreatitis. MATERIAL AND METHODS Acute pancreatitis was induced by intraperitoneal injection of cerulein in C57BL/6 wild-type mice or nuclear factor erythroid-2-related factor 2 (NRF2) gene knockout mice. LBP or normal saline was administrated by gavage once daily for one week before the induction of acute pancreatitis. At 12 hours after the first intraperitoneal injection of cerulein, the mice were euthanized. Blood and pancreatic tissue were sampled for histology and for the measurement of pro-inflammatory cytokines, serum amylase, and lipase. RESULTS In the untreated mouse model of cerulein-induced acute pancreatitis, amylase and lipase levels were increased, and these levels were reduced by LBP treatment when compared with vehicle treatment. In the untreated mouse model, histology of the pancreas showed edema and inflammation, which were reduced in the LBP-treated mice. In the untreated mouse model, increased levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were found, which were reduced in the LBP-treated mice. NRF2 gene knockout mice with cerulein-induced acute pancreatitis showed reduced anti-inflammatory effects of LBP treatment. LBP increased the expression of NRF2 and heme oxygenase-1 (HO-1). CONCLUSIONS In a mouse model of cerulein-induced acute pancreatitis, LBP reduced inflammation by upregulating NRF2 and HO-1.

[Mechanism of regulation of hepatoma cell cycle by XPD/P44 subcomplex : an in vitro experiment].

OBJECTIVE: To explore the effects of xeroderma pigmentosum group D(XPD)/P44 subcomplex on the cell cycle of the hepatoma cells. METHODS: Human hematoma cells of the line SMMC-7721 were cultured and transfected with human XPD gene by Lipofectamine and 2 strains with stably transfected plasmid pEGFG-N2 and stably transfected recombinant plasmid pEGFG-N2/XPD were selected. After stably transfection,the antisense oligonucleotides of P44 were added to treat the stably transfected cells. The cells were divided into 6 groups: Group (1) (control group), Group (2) transfected with the blank plasmid pEGFP-N2, Group (3) transfected with the recombinant plasmid pEGFP-N2/XPD, Group (4) transfected with ASODN complementary to the translation initiation site of pEGFP-N2/XPD, Group (5) transfected with antisense oligodeoxynucleotides (ASODN) complementary to the translation terminal site of pEGFP-N2/XPD, and Group (6) transfected with ASODN complementary to the translation exon5 site of pEGFP-N2/XPD. The expression levels of wild-type P44, XPD, cdk7, cdk2, c-myc, and cdc25A were detected by RT-PCR and Western blotting. The cell growth and the cell cycle were examined by MTT and flow cytometry (FCM). RESULTS: The P44 and XPD mRNA expression levels of Group (4) were significantly higher than those of Groups (1) and (2) (both P < 0.01). Western blotting indicated that the changes of P44 and XPD protein expression levels were consistent with those of their mRNAs respectively; while the mRNA and protein expression levels of cdk7, cdk2, c-myc, and cdc25A were all decreased. MTF method showed that the hepatoma cells grew slowly, FCM showed that the number of the cells arrested at the G1 stage of Group (3) were higher than those of Groups (1) and (2). After the blockage of P44 gene expression, the expression levels of XPD mRNA and protein were decreased. The XPD mRNA and protein expression levels of Groups (4), (5), and (6) were significantly higher than those of Group (3) (all P < 0.01). The mRNA and protein expression levels of cdk7, cdk2, c-myc, and cdc25A were upregulated. MT method indicated that cells grew fast. FCM showed that the numbers of the cells arrested at the G1 stage of Group (4), (5), and (6) were all lower than that of Group ((3) The expression levels of cell cycle regulatory genes including cdk7, cdk2, c-myc, and cdc25A were markedly decreased,the hepatoma cells grew slowly; after the blockage of P44 gene expression the expression levels of XPD mRNA and protein were decreased, whereas the expression levels of the cell cycle regulatory genes mentioned above were enhanced, and the hepatoma cells grew faster. CONCLUSION: XPD gene inhibits the proliferation and promotes the apoptosis of hepatoma cells. The expression of XPD may be regulated by its molecular partner P44. XPD/P44 subcomplex is involved in the regulation of DNA damage checkpoint.

[Role of hepatocellular apoptosis and mechanisms of liver injury in lipopolysaccharide-induced acute liver failure in D-galactosamine-sensitized rats].

OBJECTIVE: To investigate the situation of hepatocellular apoptosis in D-galactosamine (D-GalN)-sensitized rats with lipopolysaccharide (LPS)-induced acute liver failure and the mechanisms of liver injury therein. METHODS: Forty eight Wistar rats were randomly divided into 6 equal groups to be injected peritoneally with LPS (50 microg/kg) and D-GalN (300 mg/kg) (treatment groups) or normal saline of the same volume (control groups), and then were killed 6, 24, or 48 hours later. Blood samples were collected from the portal vein or vena cava inferior to detect the contents of serum alanine aminotransferase (ALT), livers were take out to detect the hepatocellular apoptosis by TUNEL assay or ultrastructural observations, and the expressions of iNOS, p53, and p21waf1/cip1 gene were detected by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The ALT levels of the treatment groups were all significantly higher than those of the corresponding control groups, with the peaks 24 hours after treatment. Transmission electron microscopy showed that apoptotic cells were rare in the control subgroups, but were abundant in the liver tissues of the treatment subgroups. The apoptotic indices of liver cells of the 6, 24, and 48 hours treatment subgroups were 7.3% +/- 1.5%, 71.8% +/- 10.3%, and 68.2% +/- 11.9% respectively, all significantly higher than those of the control groups (2.6% +/- 1.1%, all P < 0.05). The apoptotic index increased gradually along with the time, however, the apoptotic indices of the 24 and 48 hours treatment subgroups were not significantly different (P > 0.05). The mRNA expression levels of iNOS gene of the control subgroups, 6 hours treatment subgroup, 24 hours treatment subgroups, and 48 hours treatment subgroup were 0, 0.53 +/- 0.11, 0.36 +/- 0.08, and 0.15 +/- 0.04 respectively with a significant difference among different subgroups, and with a peak 6 hours after treatment. The p53 expressions of the control subgroups, 6 hours treatment subgroup, 24 hours treatment subgroups, and 48h treatment subgroup were 0.031 +/- 0.006, 0.022 +/- 0.008, 0.49 +/- 0.11, and 0.39 +/- 0.17 respectively, being low in both control subgroups and 6h treatment subgroup and significantly upregulated in the 24 and 48 hours treatment groups. Expression of p21waf1/cip1 was not detected in the control subgroups and 48 hours treatment subgroup, but was found in the 6 hours and 24 hours treatment subgroups, with a peak in the 24 hours treatment subgroup. CONCLUSION: Acute liver failure can be induced by low dose LPS in D-GalN-sensitized rats, which may be associated with the early high expression of iNOS gene; Apoptosis is the important morphological feature in this process.

The role of XPD in cell apoptosis and viability and its relationship with p53 and cdk2 in hepatoma cells.

We investigated the role of XPD in cell apoptosis of hepatoma and its relationship with p53 during the regulation of hepatoma bio-behavior. RT-PCR and Western blot were used to detect the expression levels of XPD, p53, c-myc, and cdk2. The cell apoptosis and cell cycle were analyzed with flow cytometry. Compared with the control cells, XPD-transfected cells displayed a lower viability and higher apoptosis rate. A decreased expression of p53 gene was detected in XPD-transfected cells. In contrast, both c-myc and cdk2 showed increased expressions of mRNAs and proteins in the transfected cells. Our results indicate that XPD may play an important role in cell apoptosis of hepatoma by inducing an over-expression of p53, but suppressing expressions of c-myc and cdk2.