Effects of lipopolysaccharides of Bacterium prodigiosum on tumor growth and immunosuppression in mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effects of lipopolysaccharides of Bacterium prodigiosum (BP-LPS) in inhibiting tumor growth and improving immunosuppression in mice.</p><p><b>METHODS</b>In mice bearing S180 tumor and a mouse model of immunosuppression induced by cyclophosphamide (CTX), the tumor growth, indexes of the immune organs and peripheral white blood cell count were measured after intraperitoneal injection of BP-LPS.</p><p><b>RESULTS</b>Injections of BP-LPS (40 U/kg) for 8 consecutive days resulted in a significant inhibition of the tumor growth in mice bearing S180 tumor (P<0.01), with a dose-dependent increase of the spleen indexes but no obvious changes in the thymus indexes. Intraperitoneal injections of BP-LPS for 7 days inhibited the reduction of peripheral white blood cells and spleen indexes in immunosuppressive mice, but did not produce any significant changes in normal mice.</p><p><b>CONCLUSION</b>BP-LPS can inhibit the tumor growth in tumor-bearing mice and enhance the immune functions of immunosuppressive mice.</p>

Establishment of mouse model of humoral immune response using rabbit red blood cells as the antigen / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a mouse model of humoral immune response by immunization with rabbit red blood cells (RRBCs).</p><p><b>METHODS</b>The mice were immunized with RRBCs and the serum hemolysin level was measured by micro-hemolysis spectrophotometry.</p><p><b>RESULTS</b>The peak time needed for hemolysin production against RRBCs was 6 days after the immunization, and 20% RRBCs in a total volume of 0.2 ml was optimal for intraperitoneal injection. Hydrocortisone (25 mg/kg) and cyclophosphamide (20 mg/kg) inhibited hemolysin production. Mannatide (4 mg/kg) produced no significant effect on serum hemolysin level in normal mice, but significantly potentiated hemolysin production in immunosuppressed mice induced by cyclophosphamide (20 mg/kg).</p><p><b>CONCLUSION</b>Intraperitoneal RRBC injection is feasible for establishing mouse models of humoral immune response.</p>

Immunomodulatory effects of Fomes fomentarius polysaccharides: an experimental study in mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the immunomodulatory effects of Fomes fomentarius polysaccharides (FFP) in mice.</p><p><b>METHODS</b>MTT assay was employed to evaluate the in vitro metabolic activity of the mouse splenocytes treated with FFP at different concentrations, and the secretion of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (INF-gamma) and interleukin 2 (IL-2) from the cells were measured by enzyme-linked immunosorbent assay. The changes in the phagocytotic activity of mouse macrophage in response to FFP treatment were evaluated by phagocytosis percentage of chicken red blood cells (CRBCs). The effect of FFP on the humoral immunity was assessed in mice immunized with sheep red blood cells (SRBCs) by measuring the serum levels of specific antibody (hemolysin) against SRBCs.</p><p><b>RESULTS</b>FFP at the concentrations of 25, 50, and 100 microg/ml all significantly enhanced the metabolic activity of mouse splenocytes in vitro and increased the production of TNF-alpha, IFN-gamma and IL-2. FFP treatment also markedly enhanced the metabolic activity of mouse peritoneal exudate cells and TNF-alpha production by the cells. At the doses of 25, 50, and 100 mg/kg, FFP significantly increased serum hemolysin level in mice immunized with SRBCs, and FFP at 50 and 100 mg/kg obviously increased the capacity of mouse peritoneal macrophages in vivo for CRBC phagocytosis.</p><p><b>CONCLUSION</b>FFP can promote the secretion of TNF-alpha, IFN-gamma and IL-2 by mouse immunocytes and enhance mouse humoral immune response and the phagocytotic activity of the macrophages.</p>

Study of dynamic changes of blood sugar and body signs in streptozotocin-induced diabetic animal models / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the dynamic changes of blood sugar and body's signs in streptozotocin diabetic animal models.</p><p><b>METHODS</b>Rat and mouse diabetic models were established by a single intraperitoneal (ip) injection and 5-day successive ip injections of streptozotocin respectively. Blood sugar levels were measured. The food consumption index (consumption of food/body weight) and the water consumption index (consumption of water/body weight) were calculated.</p><p><b>RESULTS</b>Sixty five point zero percent male rats received streptozotocin, 60 mg/kg ip, developed diabetes mellitus. The blood sugar remained in high level between the 15th day and the 25th day after injection, and it began to decline afterwards. By 5-day ip injections of streptozotocin, 40 mg/kg daily, 90.0% male mice developed diabetes mellitus. Dynamic changes of blood sugar of diabetic mouse were similar to those of rats, except that the blood sugar of mice did not decline as obvious as that of rats. The changes of water consumption index were in best fit with the changes of blood sugar in both models, with correlation index r>0.970.</p><p><b>CONCLUSION</b>The blood sugar of diabetic animal model stayed in high level from the 15th day to the 25th day after the beginning of injection. And the period is suitable for observing effect of anti-diabetic drugs. The water consumption index can reflect the blood sugar levels of diabetes animals.</p>

Effect of Ganoderma lucidum polysaccharides on tumor cell nucleotide content and cell cycle in S180 ascitic tumor-bearing mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of Ganoderma lucidum polysaccharides (GLP) on the nucleotide contents and cell cycle distribution of the tumor cells in S180 ascitic tumor-bearing mice and explore the possible mechanism of the antitumor effect of GLP.</p><p><b>METHODS</b>Mice bearing S180 ascitic tumor were subjected to intragastric administration of GLP (100, 200, and 400 mg/kg), normal saline or subcutaneous injection of cyclophosphamide (CTX) at 25 mg/kg, respectively. The treatment was given once daily for 9 consecutive days, after which the ascitic tumor cells were harvested for determination of the RNA and DNA contents and their ratio as well as the cell cycle alterations. Laser scanning confocal microscopy and acridine orange staining was performed to evaluate the DNA and RNA fluorescence intensity, and flow cytometry with propidium iodide (PI) staining was utilized for cell cycle analysis of the tumor cells.</p><p><b>RESULTS</b>Compared with normal saline group, the tumor cells in the 3 GLP groups all showed reduced RNA and DNA contents, and this reduction was statistically significant in 200 mg/kg GLP group (P=0.000). Significantly reduced RNA/DNA ratio was noted in all the 3 GLP groups (P=0.003, 0.000, 0.008 corresponding to 400, 200, and 100 mg/kg groups), suggesting that ganoderma polysaccharides more effectively reduced RNA content than DNA content. CTX also resulted in reduced RNA and DNA contents but not the RNA/DNA ratio. At the doses of 400, 200, and 100 mg/kg, GLP increased the percentage of G2/G2 phase cells (P=0.003, 0.000, and 0.000) whereas CTX showed the contrary effect (P=0.000). GLP produced no obvious effect on S-phage cells but CTX significantly reduced their percentage (P=0.000). GLP at the 3 doses all decreased the percentage of G2/M phase tumor cells (P=0.014, 0.049, 0.016) and CTX again induced contrary effect (P=0.000).</p><p><b>CONCLUSION</b>With different effects from CTX on DNA and RNA contents and cell cycle, GLP inhibits DNA and RNA synthesis in the tumor cells by mobilizing the host immune function to interfere with the normal cell cycles, which might be one of the mechanisms for the antitumor effect of GLP.</p>

Saponin from Tupistra chinensis Baker inhibits mouse sarcoma S-180 cell proliferation in vitro and implanted solid tumor growth in mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the antitumor effect of saponin extracted from Tupistra chinensis Baker (STCB) against mouse sarcoma S-180 cell proliferation in vitro and in vivo and explore the primary mechanism of this effect.</p><p><b>METHODS</b>Cytotoxic effect of STCB on S-180 cells in vitro was evaluated by MTT colorimetry, and its effect against in vitro tumor growth was tested in Kunmin mice bearing S-180 implanted tumor. The morphological and ultrastructural changes of S-180 cells after saponin treatment in vitro were examined with light and transmission electron microscope. Flow cytometry was performed to examine the cell cycle and apoptosis of S180 cells treated with different concentrations of STCB with propidium iodide staining.</p><p><b>RESULTS</b>STCB could markedly inhibit S-180 cell proliferation in vitro with 50% inhibitory concentration of 34.64 microg/ml. STCB given by intragastric administration also significantly inhibited the growth of S-180 solid tumor, and the inhibition rate exceeded 30% at the dose of 0.5 g/kg, reaching 54.86% at 2 g/kg. Electron microscopy and flow cytometry revealed increased S180 tumor cell apoptotic rate with the increment of saponin concentration, along with increased percentage of cells in S phase and decreased cells in G(2)/M phase in response to 10 or 30 microg/ml STCB treatment. At the concentration of 60 microg/ml, however, STCB resulted in an opposite effect on the cell cycles, presumably due to its interference with mitosis at high concentrations.</p><p><b>CONCLUSIONS</b>STCB inhibits the growth of S-180 cells both in vivo and in vitro possibly by inducing cell apoptosis and interfering with the cell cycle progression of the tumor cells.</p>

Ganoderma polysaccharides antagonize prostaglandin E2-induced suppression of murine splenocyte IFN-gamma and TNF-alpha mRNA expression / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine if Ganoderma polysaccharides can antagonize prostaglandin E2 (PGE2)-induced suppression of murine splenocyte interferongamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) mRNA expression.</p><p><b>METHODS</b>Mixed lymphocyte culture reaction was used as the experimental model. The expressions levels of IFN-gamma and TNF-alpha mRNA were measured by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>After the cultures were treated with PGE2 for 4 h, IFN-gamma mRNA expression was reduced as compared with the control, which was especially obvious when PGE2 concentrations exceeded 10 micromol/L (P<0.01). Ganoderma polysaccharides above 100 mg/L showed partial antagonistic effect against the inhibition of IFN-gamma by PGE2 at the fixed concentration of 20 micromol/L. Further studies indicated that PGE2 (20 micromol/L) impaired the expression of TNF-alpha mRNA after an 8-hour incubation and Ganoderma polysaccharides above 100 mg/L could partially antagonize this effect.</p><p><b>CONCLUSION</b>Ganoderma polysaccharides can partially antagonize PGE2-induced suppression of murine splenocyte IFN-gamma and TNF-alpha mRNA expression.</p>