[Enhancing effect of matrine on the tumor-inhibition by TIM2 gene-modified hepatocarcinoma H22 cells in mice].

OBJECTIVE: To investigate the effects of matrine on the anti-tumor efficiency of TIM2 gene-modified murine hepatocarcinoma H22 cells. METHODS: A combined eukaryotic expression vector pIRES2-EGFP-TIM2 was constructed and transfected into H22 cells by lipofectamin. The monoclone of positive H22-TIM2 cells and negative control H22-EGFP cells transfected with pIRES2-EGFP vector were selected by G418 pressure and limited dilution method in turn and were inoculated to establish the tumor-bearing mouse model. Next, matrine was administered to the tumor-bearing mice and the inhibitory effect of matrine was determined. RESULTS: The co-expression of EGFP protein and TIM2 gene was detected in H22 cells selected after TIM2 gene transfecion. After subcutaneous injection of H22-TIM2 cells, the rate of tumor formation (41%) was lower than that of H22 cells and H22-EGFP cells injection (92%) in mice. The tumor growth was significantly inhibited in mice vaccinated with H22-TIM2 cells. After the experiment was completed, the volume of tumors in mice of H22-TIM2 group was 31.34 +/- 9.21 mm3, smaller than those in H22-EGFP group (98.25 +/- 25.23)mm3 and H22 cells group (114.08 +/- 36.45)mm3 (P < 0.01). Matrine dramatically enhanced the anti-tumor efficiency of TIM2 gene-modified H22 cells, with the highest tumor inhibitory rate (IR) 90.6% among the H22-TIM2 group, matrine treatment group and H22-EGFP cells combined with matrine treatment group (69.2%, 67.5% and 70.8%, respectively) in the experimental mice. CONCLUSION: The tumorigenesity of H22 cells has been markedly impaired after modification by TIM2 gene. Matrine can enhance its inhibitory effect on tumors of H22-TIM2 cells in vivo. These data indicate importance to further study on the biological role of TIM2 gene in tumor immunity and explore the molecular mechanism of matrine in suppressing of tumor growth.

[Effects of matrine on oncogenicity of H22 cells modified by TIM2 gene in vivo].

OBJECTIVE: To investigate the effects of matrine on the anti-tumor efficiency of H22 murine hepatocarcinoma cell-based vaccine modified by TIM2 gene in vivo. METHOD: The combinant eukaryotic expression vector pIRES2-EGFP-TIM2 was constructed and transfected into H22 cells by lipofectamin. The monoclone of the positive H22-TIM2 cells and negative control H22-EGFP cells were selected by G418 pressure and limited dilution method in turn. The H22 whole-cell-based vaccine were inoculated to establish the tumor-bearing mouse model, and its oncogenicity and immunogenicity were observed in vivo. Then the matrine was administered to the tumor-bearing mice inoculated by H22-TIM2 cells, H22-EGFP cells and H22 cells, and the inhibitory effect of matrine on tumor was studied. RESULT: The co-expression of EGFP protein and TIM2 mRNA were detected in H22-TIM2 cells. The rate of tumor formation in mice injected of H22-TIM2 cells was 41%, lower than that of H22 cells and H22-EGFP cells injection (92%) in mice. The growth of tumor were significantly inhibited vaccinated with H22-TIM2 cells in mice. The inhibitory rate of tumor (IR) was 69.2% in mice of H22-TIM2 group, higher than that of mice treated with matrine and H22 cells injection, the later was 67.5%. Matrine could dramatically strengthen the anti-tumor efficiency of H22 cells modified by TIM2 gene, with the highest tumor inhibitory rate (IR) (90.6%) in all the experimental mice. The spleen index, populations of CD4-positive lymphocytes and the ratio of CD4-positive to CD8-positive lymphocytes of spleen in mice vaccinated of H22-TIM2 cells were obviously higher than those in the other groups. CONCLUSION: The oncogenicity of H22 cells is markedly impaired after modified by TIM2 gene. Matrine can strengthen the inhibitory effect of H22-TIM2 cells on tumor in mice. These data give us important clues to further study the biological role of TIM2 gene in tumor immunity and explore the molecular mechanism of matrine in suppressing tumor.

[Changes in electroencephalograph and somatosensory evoked potential and their relationship with neuron apoptosis in rat after ischemic insult to brain].

OBJECTIVE: To study the changes in electroencephalograph (EEG) and somatosensory evoked potential (SEP) and their relationship with neuron apoptosis in rat after ischemic insult to the brain. METHODS: Thirty-five SD rats were randomly divided into normal, sham operated and 3, 12, 24, 48, 72 hours after ischemia/reperfusion (I/R) groups with 5 rats in each group. The ischemia of brain was produced by clamping 4 vessels to the brain for various periods of time. Changes in EEG and SEP were recorded at different time after I/R, and the amounts of apoptotic neurons in hippocampus and cortex after I/R were assessed with terminal deoxynucleotidyl transferase mediated dUTP biotin nick end labeling (TUNEL) and acridine orange ethidium bromide (AO/EB) fluorescence examination techniques. RESULTS: Compared with sham operated group, EEG amplitude decreased significantly (all P<0.05), and the proportion of Delta wave increased significantly after ischemia of the brain (all P<0.05). The latent period of P1 wave crest extended markedly (all P<0.05), and P1-N1 amplitude decreased significantly after I/R (all P<0.05). EEG and SEP changes were correlated with the apoptosis and loss of neurons, which started in the hippocampus and extended to frontal cortex and parietal cortex. CONCLUSION: The combined analysis of EEG and SEP can reflect the process of neuron apoptosis, which is helpful for the diagnosis and evaluation of prognosis of patients suffering from cerebral ischemia.

The effect of transformation on the virulence of Streptococcus pneumoniae.

Although pneumococcus is one of the most frequently encountered opportunistic pathogen in the world, the mechanisms responsible for its infectiveness have not yet been fully understood. In this paper, we have attempted to characterize the effects of pneumococcal transformation on the pathogenesis of the organism. We constructed three transformation-deficient pneumococcal strains, which were designated as Nos. 1d, 2d, and 22d. The construction of these altered strains was achieved via the insertion of the inactivated gene, comE, to strains 1, 2 and 22. We then conducted a comparison between the virulence of the transformation-deficient strains and that of the wild-type strains, via an evaluation of the ability of each strain to adhere to endothelial cells, and also assessed psaA mRNA expression, and the survival of hosts after bacterial challenge. Compared to what was observed with the wild-type strains, our results indicated that the ability of all of the transformation-deficient strains to adhere to the ECV304 cells had been significantly reduced (p < 0.05), the expression of psaA mRNA was reduced significantly (p < 0.05) in strains 2d and 22d, and the median survival time of mice infected with strains 1d and 2d was increased significantly after intraperitoneal bacterial challenge (p < 0.05). The results of our study also clearly indicated that transformation exerts significant effects on the virulence characteristics of S. pneumoniae, although the degree to which this effect is noted appears to depend primarily on the genetic background of the bacteria.

[Inhibition of tumor growth in tumor-bearing mice treated with matrine].

OBJECTIVE: To investigate the inhibitory effect of matrine on tumor growth in tumor-bearing mice and explore its possible mechanisms of anti-tumor action in vivo. METHODS: Hepatocellular carcinoma cells H(22) were subcutaneously injected into BALB/c mice and matrine was administered to the tumor-bearing mice. The kinetics of tumor formation and tumor growth were measured, tumor growth inhibition rate (IR) was calculated, and tumor tissue samples were taken and examined by light and electron microscopy to assess the inhibitory effects of matrine on tumor growth in the mice. RESULTS: Marked inhibitory effect of matrine on the transplanted hepatocellular carcinoma H(22) was observed in the tumor-bearing mice. The inhibitory rates were 62.5% and 60.7% in the groups treated with high and low dosage of matrine, respectively (P < 0.01 vs. control group). The tumor formation was significantly retarded and tumor growth was inhibited in matrine-treated groups compared with those in control mice. Histopathological examination revealed widespread necrosis with massive accumulation of infiltrating lymphocytes and plasmacytes in the tumors. Numerous apoptotic cells and apoptotic bodies were observed in the tumors under the electron microscope. CONCLUSION: Matrine has marked inhibitory effects on tumor growth in vivo, which is probably related to inhibition of cell division and tumor cell proliferation, directly killing of tumor cells and/or induction of apoptosis and modulation of anti-tumor immune responses.

Characterization of a novel C-type lectin-like gene, LSECtin: demonstration of carbohydrate binding and expression in sinusoidal endothelial cells of liver and lymph node.

A new C-type lectin-like gene encodes 293 amino acids and maps to chromosome 19p13.3 adjacent to the previously described C-type lectin genes, CD23, dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), and DC-SIGN-related protein (DC-SIGNR). The four genes form a tight cluster in an insert size of 105 kb and have analogous genomic structures. The new C-type lectin-like molecule, designated liver and lymph node sinusoidal endothelial cell C-type lectin (LSECtin), is a type II integral membrane protein of approximately 40 kDa in size with a single C-type lectin-like domain at the COOH terminus, closest in homology to DC-SIGNR, DC-SIGN, and CD23. LSECtin mRNA was only expressed in liver and lymph node among 15 human tissues tested, intriguingly neither expressed on hematopoietic cell lines nor on monocyte-derived dendritic cells (DCs). Moreover, LSECtin is expressed predominantly by sinusoidal endothelial cells of human liver and lymph node and co-expressed with DC-SIGNR. LSECtin binds to mannose, GlcNAc, and fucose in a Ca(2+)-dependent manner but not to galactose. Our results indicate that LSECtin is a novel member of a family of proteins comprising CD23, DC-SIGN, and DC-SIGNR and might function in vivo as a lectin receptor.

[Effect of inducible nitric oxide on intracellular homeostasis of hepatocytes].

OBJECTIVE: To investigate the effects of inducible nitric oxide (NO) and exogenous NO on the intracellular homeostasis of the hepatocytes. METHODS: Endogenous NO was induced by combined action of lipopolysaccharide (LPS) and cytokines in cultured rat hepatocytes, and exogenous NO was supplied by sodium nitroprusside (SNP) to stimulate the hepatocytes. The changes in intracellular malondialdehyde (MDA), reduced glutathione(GSH) and free calcium ([Ca2+]i) were observed. RESULTS: substantial increase by 7.97 times in intracellular MDA level and a decrease by 57.9% in GSH occurred in the hepatocytes after the cells had been incubated with LPS and cytokines for 24 h, which were reversed by 43.5% and 98.4% respectively by treatment with N(G)-monomethyl-L-arginine (NMMA), a competitive nitric oxide synthase (NOS) inhibitor. Verapamil significantly reduced both endogenous NO production and oxidative stress, while the effect of A23187 was not conspicuous. Incubation with chlorpromazine and Vitamine E (VitE), however, did not result in decreased release of NO by LPS- and cytokines-induced hepatocytes. After SNP exposure of the hepatocytes, the oxidative status was reversibly enhanced in a time-dependent manner. Short exposure to SNP led to a concentration-dependent inhibition of the rapid and transient increase in free calcium induced by K(+) depolarization and hepatopoietin-coupled calcium mobilization. CONCLUSIONS: Inducible NO may initiate and play a key role in the latter stages of metabolic and functional stress responses of hepatocytes against endotoxin and cytokines, when the reduction occurs in the capacity of NO to independently mediate lipid peroxidation and counteract oxidation. The inhibitory effect of NO on [Ca2+]i mobilization may be an important autoregulatory mechanism by means of negative feedback on protein kinase C-associated NOS induction.