Regulatory effects of lipopolysaccharide in murine macrophage proliferation

AIM:To study the regulatory effects of bacterial lipopolysaccharide (LPS) in murine macrophage proliferation.METHODS:Using murine peritoneal exudate macrophage (PEM) and macrophage cell line J(774) A.1 as targets, LPS effects on M-CSF and granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulated macrophage colony-forming cells (CFU-M) were detected. (125)I-GM-CSF receptor binding assay was used to examine LPS regulation on GM-CSF receptor expres-sion.RT-PCR was employed to test TGF-beta(1) inhibition on IFN-gamma mRNA expression on macrophage induced by LPS.RESULTS:Without direct effect on macrophage proliferation, LPS could inhibit the macrophage proliferation stimulated by GM-CSF.However,with the concomitant existence of GM-CSF and TGF-beta(1), the LPS inhibitory effect was eliminated.RT-PCR analysis indicated that the strongest mac-rophage growth inhibitory factor IFN-gammamRNA expression in macrophage induced by LPS was remarkably suppressed by TGF-beta(1), (125)I-GM-CSF receptor binding assay showed that LPS could enhance GM-CSF receptor expression likewise as TGF-beta(1).CONCLUSION:LPS is involved in the network of macrophage proliferative regulation by multiple cytokines, displaying inhibitory and stimulatory effects based on the coexisting cytokines.

Effects of combined use of diallyl disulfide and Nacetyl-cysteine on acetaminophen hepatotoxicity in beta-naphthoflavone pretreated mice

AIM:To assess the protective effect of diallyl disulfide (DADS) and its combined use with N-acetyl-cysteine (NAC) on acetaminophen (APAP) hepatotoxicity in C57BL/6N (B6) mice pretreated with beta-naphthoflavone (BNF).METHODS:B6 mice were divided into six groups and all compounds used were injected intraperitoneally. Except for control and APAP group (receiving APAP only), the other groups received an injection of APAP (350mg/kg) 48 hours after BNF (200mg/kg) and either of DADS (200mg/kg), or NAC (500mg/kg) or both DADS and NAC.DADS was given 2 hours before APAP and NAC was injected with APAP.The mean survival time was recorded and livers were examined histologically.Hepatic glutathione (GSH) levels and plasma ALT were also determined at different time points.To evaluate the effect of DADS or NAC on hepatic P450 induction by BNF,liver microsomes were prepared and 7-ethoxyresorufin O-dealkylase (ERD) activity was determined using spectrofluorometrical methods. In vitro effect of DADS or NAC on ERD activity was assayed by directly incubating microsomal suspension with DADS or NAC of different concentrations.RESULTS:APAP was not toxic to mice without BNF pretreatment, but caused severe liver necrosis and death of all BNF-treated mice in 4 hours. A sharp depletion of GSH (approximately 62% of its initial content at 2 hours and 67% at 4 hours) and a linear elevation of ALT levels (536.8 plus minus 29.5 Sigma units at 2 hours and 1302.5 plus minus74.9 at 4 hours) were observed.DADS and NAC given individually produced mild protection,resulting in prolonged survival,a slower decline of GSH level and a less steeper elevation of ALT level.All mice died eventually. Co-administration of DADS and NAC completely protected mice.GSH level in this group lowered by about 35% and 30% at 2 and 4 hours, and ALT was 126 plus minus 18 and 157.5 plus minus 36.6 Sigma units at 2 and 4 hours. ERD activity in BNF-treated mice was about 5 times that of the constitutive level determined in normal mice. Neither DADS nor NAC inhibited P450 1A1/1A2 induction as determined by their effect on the induction of ERD activity.In vitro assay indicates that DADS,but not NAC,was a potent inhibitor of ERD activity(IC(50) = 4.6&mgr;m).CONCLUSION:A combined use of both DADS and NAC produced full protection in BNF treated mice against APAP hepatotoxicity.The mechanism is that DADS inhibits P450 1A1/1A2 activity, but not induction, which substantially reduces production of NAPQI, while NAC enhances liver detoxifying capability via serving as a precursor of GSH and stimulating GSH synthesis.

Endotoxins enhance hepatocarcinogenesis induced by oral intake of thioacetamide in rats

AIM:To clarify whether endotoxin is of pathogenic importance for hepatocarcinogenesis,or the increased cancer risk results solely from the cirrhotic process.METHODS:The rat model of hepatoma was treated by the intake of 0.03% thioacetamide in drinking water for six months. During induction of hepatoma, rats were additionally treated with splenectomy and/or lipopolysaccharide administration.The liver nuclear DNA index and proliferation index were quantitatively analyzed by flow cytometry. Hepatic histology was examined with light and electron microscopes. Plasmic endotoxin concentration and gamma-glutamyl transpeptidase activity were measured, and hepatoma incidence was recorded.RESULTS: Thioacetamide induced cirrhosis and hepatoma in Wistar rats with histology or regenerative nodule, fibrosis and neoplastic foci were quite similar to the pathogenic process of human cirrhosis leading to hepatoma. In comparison with TAA controls (DNA index: 1.15 plus minus 0.21), exo-endotoxin increased the DNA index by 7.8% (1.24 plus minus0.25, P < 0.02) and hepatoma rate by 16.7. Splenectomy-induced enteric endotoxemia increased the DNA index by 25% (1.44plus minus0.15, P < 0.01) and hepatoma rate by 33%. A summation of the effects of these two factors increased the DNA index by 36% (P < 0.01)and hepatoma incidence by 50%, moreover, the level of endotoxemia showed a close relation with DNA index (r = 0.96, P < 0.01), as well as with the occurrence rate of hepatoma (r = 0.00, P < 0.01). Histological findings further verified such alterations.CONCLUSION:Lipopolysaccharide administration and/or splenectomy-induced enterogenic endotoxemia may enhance rat hepatocarcinogenesis induced by oral intake of thioacetamide.

Evaluation of various solutions for small bowel graft preservation

AIM:To elucidate the effect of various solutions for small bowel graft preservation in pigs under hypothermic storage.METHODS:The swine segmental small bowel graft was autotransplanted after it was preserved with lactated Ringer's (LR), Euro-Collins (EC), hyperosmolarity citrate adenine (HC-A) and WMO-1 solutions for 10,18 and 24 hours,respectively.The recipient survival rate, morphological structure, graft mucosal energy substances and Na( +) -K(+) ATPase activity were studied,and graft absorption was estimated with D-xylose absorption test.RESULTS:The morphological study of the grafts preserved with LR or HC-A solution for 10 hours or with EC and WMO-1 solution for 18 hours was normal 6days after operation. Mucosal ATP,total adenine nucleotides (TAN) contents and Na( +) -K(+)ATPase activity of the graft preserved with EC or WMO solution were higher than that of the graft preserved with LR or HC-A solution.Serum level of D-xylose was higher in EC and WMO-1 groups than in LR and HC-A groups when the graft was preserved for 24 hours.CONCLUSION:EC and WMO-1 solutions can preserve the swine small bowel up to 18 hours, which are superior to LR and HC-A solutions.

Significance of vascular endothelial growth factor messenger RNA expression in gastric cancer

AIM: To study VEGF mRNA expression in gastric carcinoma and to clarify the association of its expression with the clinicopathologic features of the disease.

METHODS: In situ hybridization (ISH) and histochemistry were used to examine and analyze the expression of VEGF mRNA and antigen, and microvessel count (MVC) in 28 cases of gastric carcinomatous tissue in combination with clinical materials.

RESULTS: Ninteen of 28 gastric carcinomas were positive for VEGF mRNA. VEGF mRNA was mainly expressed in malignant cells and not in normal epithelium of gastric mucosa. Its expression was further increased in tumor cells adjacent to tumor necrosis zones, where stromal cells expressed VEGF mRNA occasionally. There was a close correlation between MVC and VEGF mRNA positivity (P < 0.005). High VEGF mRNA levels were significantly associated with serosal invasion, lymph node metastasis and TNM staging ( P < 0.05, respectively).

CONCLUSION: VEGF mRNA expression is associated with tumor invasion and metastasis by stimulating angiogenesis in gastric carcinoma.

Simplified isolation and spheroidal aggregate culture of rat hepatocytes

AIM: To explore a simplified method for isolation of hepatocytes and establish a method of primary hepatocyte culture with more aggregates and longer persisence.

METHODS: Wistar rat hepatocytes were isolated by a single extracorporeal two-step perfusion method, and the cells were seeded on poly-HEMA coated flasks and cultured with hormonally defined medium and gentle shaking at regular intervals.

RESULTS: The total yield of isolating hepatocytes amounted to 10⁸ cells for each rat liver with the viability of more than 90% in all isolations. Under the nonadherent environments, the cells were found to attach to each other and form multicellular aggregates rapidly, and the aggregates became spheroidal shape after two days in culture. The morphologic characteristics and albumin synthetic function of the multicellular spheroidal aggregates can be maintained for one month.

CONCLUSION: The simple and reliable isolation as well as large scale and longer time culture of hepatocytes can be used for experiments in liver cell transplantation and bioartificial liver support system.

Arterial chemoembolization for hepatocellular carcinoma

AIM: To study the therapeutic effects of transcatheter arterial three-segment chemoembolization for hepatocellular carcinoma (HCC).

METHODS: According to the anatomy of vessels, the tumor capillary networks, muscular arterioles and feeding arteries were successively occluded using lipiodol ultra-fluid (LUF), sinobufagin microsphere (SBMs) and particles of gelatin sponge (PGS). In this series of 80 cases, therapeutic effects were evaluated in 76 cases.

RESULTS: There were 22 cases (28.9%) with partial response and 41 (53.9%) with minor response in the 76 evaluated patients. The 6-month, 1-year, 2-year and 3-year survival rates were 97.4%, 86.8%, 46.1% and 27.6% respectively.

CONCLUSION: This regimen was a rational chemoembolization method for HCC patients.

CCR5 gene expression in fulminant hepatitis and DTH in mice

AIMS: To isolate mouse CCR5 cDNA (muCCR5) and study its expression in vivo.

METHODS: Marathon PCR was used to isolate muCCR5 cDNA and two animal models were designed to investigate the gene expression in vivo, one was mouse fulminant hepatitis induced by Propionibacterium acnes (P.acnes) and the other was that with delayed type hypersensitivity reaction (DTH). A specific GST-NH2-terminus of muCCR5 fusion protein antibody F(ab’)2 was prepared and clarified. RT-PCR and immunohistochemical analysis were used to observe the expression level of CCR5 gene in mice.

RESULTS: A positive reaction of mouse macrophage was found in DTH but not expressed in P.acnes induced fulminant hepatitis by RT-PCR and immunohistochemical analysis.

CONCLUSION: This muCCR5 expression may be involved in an allergic processmediated by cellular immunity but not acute inflammatory reaction induced by P.acnes.

Induction of apoptosis of lymphocytes in rat mucosal immune system

AIM: To undergo apoptosis during negative and positive selection processes in rat mucosal immune system which are implicated in the pathogenesis of various mucosal diseases.

METHODS: Female Sprague-Dawley rats were given protein synthesis inhibitor, cycloheximide, intravenously or intraperitoneally, an apoptosis was recognized by morphological hallmark under light and electronmicroscopy, and the expression of proliferating cell nuclear antigen was visualized immunohistochemically.

RESULTS: The apoptosis of mucosal lymphocytes in the digestive tract, as well as in trachea, uterus and lacrimal gland was induced by cycloheximide ( > 1.0 mg·kg^-1 body weight), which were located mainly in lamina propria and germinal centers of lymphoid nodules. At the same time, a portion of crypt epithelial cells of proliferating zone in small and large intestine, and the epithelial cells in genital tract were also found to undergo apoptosis. Immunostainings showed that apoptotic cells expressed proliferating cell nuclear antigen.

CONCLUSION: Apoptosis of lymphocytes in mucosal immune system can be induced by cycloheximide. This model will facilitate the understanding of normal mucosal immune system and its role in the pathogenesis of related diseases such as inflammatory bowel diseases.

Tumor radioimmunoimaging of chimeric antibody in nude mice with hepatoma xenograft

AIM: To study the radioimmunoimaging (RAII) using the human/mouse chimeric Ab to evaluate its targeting activity in animal models.

METHODS: To chimeric Ab was labeled with ¹³¹I. RAII was performed at different intervals after injection of radio-labeled Abs in nude mice with human hepatoma xenograft, and tissue distribution of radioactivity was measured. Comparison was made in the chimeric Ab between the single segment Ab and previous murine mAb against HBxAg.

RESULTS: The experimental objects developed tumor-positive image after 2 days of radio-labeled Abs injection, and the peak accumulation of radioactivity fell on the 7th day. The tumor/liver ratioactivity of the chimeric Ab, single segment Ab, anti-HBx mAb, and the control group was 281 ± 0.21, 2.44 ± 0.16, 4.60 ± 0.19, and 0.96 ± 0.14, respectively.

CONCLUSION: The genetic engineering Abs have a considerable targeting activity which can be used as a novel humanized vector in the targeting treatment of liver cancer.

CEA and AFP expression in human hepatoma cells transfected with antisense IGF-I gene

AIM: To determine whether antisense insulin-like growth factor-I (IGF-I) gene can modulate CEA and AFP expression in human hepatoma cells (HepG2).

METHODS: Transfection of HepG2 cells was accomplished using Lipofectin reagent. Northern blot analysis confirmed the antisense IGF-I RNA of the transfected cells. CEA and AFP levels were measured using radioimmunoassay.

RESULTS: Human hepatoma cell lines (HepG2) were transfected with antisense IGF-I gene. Northern blot analysis confirmed that antisense IGF-I RNA was expressed in the transfected cells. The effect of antisense IGF-I gene on CEA and AFP expression was demonstrated by the fact that the CEA and AFP levels in the supernatant of transfected cell culture were significantly lower as compared with the parent cells, [CEA 7.0 μg/L ± 0.76 μg/L and 3.29 μg/L ± 1.80 μg/L (P < 0.05) and AFP 53.63 μg/L ± 6.02 μg/L and 9.0 μg/L ± 5.26 μg/L (P < 0.01), respectively].

CONCLUSION: The malignant potentiality of the transfected cells was partially suppressed.Antisense IGF-I gene can modulate the expression of CEA and AFP in human hepatoma cell lines (HepG2)

Bile acids in serum and bile of patients with cholesterol gallstone

AIM: To analyze serum bile acids and biliary lipids of patients with cholesterol gallstone(CS) and explore the relationship between deoxycholic acid (DCA) and CS disease.

METHODS: Analysis of bile acids in serum was done with gas-chromatography in two groups: CS group (n = 151) and control group (n = 256). Serum bile acids and biliary lipids were also studied in 90 matched samples.

RESULTS: The serum DCA was 0.955 μmol/L ± 0.078 μmol/L in CS group, which was more than that of control group (0.696 μmol/L ± 0.047 μmol/L), P < 0.01. The ratio of DCA/chenodeoxycholic acids (CDCA) was 1.76 ± 0.30 in CS group, about two times that in control group (0.92 ± 0.14). The mole percent of DCA in bile was positively related to cholesterol saturation index (CSI) (P < 0.01) and the mole percent of CDCA in bile negatively to CSI (P = 0.01). There was correlation between the mole percent of DCA, CDCA and cholic acid in bile and in serum.

CONCLUSION: It is suggested that DCA is lithogenic and the increased amount of DCA or the ratio of DCA/CDCA in serum may be one of the features of cholesterol gallstone patients.

Cloning of 3H11 mAb variable region gene and expression of 3H11 human-mouse chimeric light chain

AIM: To clone mouse anti-human gastric cancer mAb (3H11) variable genes and to construct 3H11 human-mouse chimericantibody.

METHODS: The entire VH and VL genes of anti-gastric cancer mAb 3H11 were cloned by RT-PCR method from 3H11 hybridoma cells, using 5’ primers for leader sequences. The 3H11 VL gene was then inserted into human-mouse chimeric light chain expression vector and transfected into murine Sp2/0 myeloma cells.

RESULTS: DNA sequence analysis indicated that the cloned genes included the whole leader sequences and the mature Ig variable region encoding sequences. Aftergene transfection, transient expression of chimeric light chain protein was detected.

CONCLUSION: DNA sequences and transient expression indicated that the cloned gene was functional. This work laid basis for constructing 3H11 human-mouse chimeric antibody in the future.

Expression of somatostatin mRNA in various differentiated types of gastric carcinoma

AIM: To investigate the expression of somatostatin mRNA in various differentiated types of gastric carcinoma.

METHODS: By using in situ hybridization and immunohistochemical techniques, the expression of somatostatin mRNA and somatostatin immunoreactivity in the normal gastric mucosa, the poorly, moderately and well-differentiated gastric carcinomas, and various clinical stages of carcinoma were observed.

RESULTS: In comparison with the normal gastric mucosa, the significantly increased expression of somatostatin mRNA positive cells was displayed in gastric carcinoma ( t = 2.681, P < 0.01). The positive signal cells were distributed in a scattered form or aggregated as a mass or a cord, and the positive cells were more significantly enhanced in poorly differentiated carcinomas than those in well and moderately differentiated carcinomas (t = 2.962, P < 0.01). The somatostatin mRNA hybridization signals in stages III and IV of gastric carcinoma were significantly higher than those in stages I and II. The results of somatostatin immunoreactivity were consistent with those of in situhybridization.

CONCLUSION: The alteration of the expression of somatostatin mRNA was associated with the deve-lopment of gastric carcinoma and may play an important role in the process of tumor differentiation.

Relationship between HBV viremia level of pregnant women and intrauterine infection: neated PCR for detection of HBV DNA

AIM: To determine the incidence of hepatitis B virus (HBV) in trauterine infection and to explore the relationship between HBV viremia level of pregnant women and HBV intrauterine infection.

METHODS: Sixty-nine pregnant women were divided into three groups. Group A, 41 HBsAg positive patients, 14 of them were HBeAg positive (group A1), and 27 HBeAg negative (group A2); Group B, 12 HBsAg negative patients, but positive for anti-HBs and/or anti-HBe and/or anti-HBc; and Group C, 16 patients negative for all HBV markers. Blood samples of mothers were taken at delivery, samples of their infants were collected within 24 h after birth (before injection of HBIG and HBV vaccine). All the serum samples were stored at - 20 °C. HBV serum markers were tested by radioimmunoassay and HBV NDA were detected by nested polymerase chain reaction.

RESULTS: In group C, all of 16 newborns were negative for HBsAg and HBV DNA. In group A, 7 infants were HBsAg positive (17.1%), and 17 (41.5%) were HBV DNA positive (P < 0.05). The incidence of intrauterine HBV infection was much higher in group A1 than that in group A2 (HBsAg 42.9% vs 3.7%, HBV DNA 92.9% vs 14.8%, P < 0.05). The incidence of HBV intrauterine infection was significantly different between high and low HBV viremia of mothers (93.3% vs 42.9%, P < 0.05).

CONCLUSION: The incidence of HBV intrauterine infection is high when HBV DNA in newborns detected with nested PCR is used as a marker of HBV infection. It is related to HBV viremia level of mothers.

Effect of aging on cytoskeleton system of Kupffer cell and its phagocytic capacity

AIM: To investigate the age-related alterations of cytoskeleton system in liver Kupffer cell and their relation to the changed phagocytic function.

METHODS: The phagocytic function of Kupffer cells from rats of various ages (6 mo, 12 mo,18 mo and 24 mo) were quantitatively evaluated by phagocytosis of polystyrene beads. The actin distribution and measurement of Kupffer cell were determined by a phalloidin-TRITC method; and the myosin and vimentin distribution and measurement with indirect immunochemical staining.

RESULTS: Aging resulted in significant alterations of actin, myosin and vimentin distributions and reductions in Kupffer cell; the 3 cytoskeleton components of 24-mo-old Kupffer cell were significantly decreased to 68.0%, 84.9% and 75.5%, respectively of these of 6-mo-old Kupffer cell(P < 0.01,0.01 and 0.01). And these decreases had significant positive relations with the damaged phagocytosis of the aged Kupffer cell. γ values were 0.96(P < 0.05), 0.99(P < 0.01) and 0.95 (P < 0.05) respectively.

CONCLUSION: The cytoskeleton system of the aged Kupffer cell presents an evident state of senescence, which may be an important mechanism of decreased phagocytosis of the aged Kupffer cell.

Immunohistochemical detection of HCV infection in patients with hepatocellular carcinoma and other liver diseases

AIM: To detect HCV infection in patients with HCC and other liver diseases by the immunohistochemical method.

METHODS: The expression of HCV antigen was identified by means of LSAB (labelled streptavidin-biotin) method using anti-NS3 monoclonal antibody.

RESULTS: The positive rates of HCV antigen in the three groups of HCC, liver cirrhosis and hepatitis were 13.5% (7/52), 12.5% (2/16), and 10% (4/40) respectively, while in the samples from patients with constitutional jaundice and normal liver samples, no HCV antigen was found. HCV antigen could be seen in the nuclei and/or cytoplasms of carcinoma cells and/or pericancerous hepatocytes. In HCC, HCV antigen was more often seen in nuclei than in cytoplasms. The positive rate of HCV antigen in pericancerous tissues was higher than that in cancerous tissues.

CONCLUSION: HCV is associated with HCC, and HCV infection enhances the development of liver diseases. HCV affects the initiative period of HCC and induces the malignant phenotypic alteration of hepatocytes.

Establishment of a nonradioactive assay for2’-5’ oligoadenylate synthetase and its application in chronic hepatitis C patients receiving interferon-α

AIM: To establish a nonradioactive assay for 2’-5’ oligoadenylate synthetase (2-5 AS) and to measure the 2-5AS in peripheral blood mononuclear cell (PBMC) extracts of patients with chronic hepatitis C before IFN-α injection, 24 h and one month after the first injection.

METHODS: 2-5AS in cell extracts of PBMCs from 10 normal persons and 15 chronic hepatitis C patients were determined with PEI cellulose thin-layer chromatography.

RESULTS: The assay of 2-5AS in human PBMC was found to be rapid, sensitive, specific and reliable. The 2-5AS activity of PBMC in normal persons was in a quite low level (2.0%), and it was increased about ten-folds after stimulation of IFN (19.7%), (P < 0.01). In 15 chronic hepatitic C patients, the basal levels of 2-5AS before IFN treatment were higher than those of normal persons, being much higher in the group showing poor response to IFN treatment, but 24h after the first injection of IFN-α the 2-5AS level showed a more rapid and much greater rise in those patients with a good response.

CONCLUSION: 2-5AS may be a useful parameter of biological response during the IFN therapy.

Aflatoxin sufferer and p53 gene mutation in hepatocellular carcinoma

AIM: To study the p53 gene mutation and its relationship to aflatoxin B1 exposure in hepatocellular carcinoma (HCC).

METHODS: Restriction fragment length polymorphism analysis method was used in 62 HCC samples, and DNA direct sequencing in another 45 HCC samples.

RESULTS: In HCC and AFB1 high and low-risk areas, 36/52 (69%) and 2/10 (20%) cases were found losing the HaeIII allele respectively, suggesting one of the base G mutation at the p53 gene codon 249. Similar results appeared in DNA direct sequencing, 20/35 (57%) and 1/10 (10%) respectively mutated at the codon 249 third base G to C transversion.

CONCLUSION: In HCC after AFB1 exposure, mutation of p53 gene is fixed at codon 249 third base and take the form of G to T transversion. This is a definite marker of mutation which is induced by AFB1 mutagen. It is applicable for molecular epidemiologic survey of the sufferers of AFB1 among HCC cases and for discovering more unknown natural AFB1 contaminated areas.

A new rat model of portal hypertension induced by intraportal injection of microspheres

AIM: To produce a new rat model of portal hypertension by intraportal injection of microspheres. METHODS: Measured aliquots of single or different-sized microspheres (15, 40, 80μm) were injected into the portal vein to block intrahepatic portal radicals. The resultant changes in arterial,portal,hepatic venous and splenic pulp pressures were monitored. The liver and lungs were excised for histological examination.

RESULTS: Portal venous pressure was elevated from basal value of 0.89-1.02 kPa to a steady-state of 1.98-3.19 kPa following the sequential injections of single- or different-sized microspheres, with a markedly lowered mean arterial pressure. However, a small-dose injection of 80 μm microspheres (1.8 × 10⁵) produced a steady-state portal venous pressure of 2.53 × 0.17 kPa, and all rats showed normal arterial pressures. In addition, numerous microspheres were found in the lungs in all experimental groups.

CONCLUSION: Portal hypertension can be reproduced in rats by intraportal injection of microspheres at a small dose of 80 μm (1.8 × 10⁵). Intrahepatic portal-systemic shunts probably exist in the normal rat liver.