Porcine reproductive and respiratory syndrome virus reinfection causes the distribution of porcine interleukin-4 in close proximity to B lymphocytes within lymphoid follicles and a reduction in B and T lymphocytes.

Interleukin 4 (IL-4) plays a major role in T-lymphocyte development and is thought to be a central regulator as a cofactor in resting B-lymphocyte proliferation. Primary infection with porcine reproductive and respiratory syndrome virus (PRRSV) induces minimal IL-4 production, whereas an IL-4 response occurs in the peripheral blood of piglets reinfected by PRRSV. The locations and interaction partners for the massive volume of IL-4 triggered by PRRSV reinfection remain unclear. This study aimed to investigate the characteristics of IL-4 secretion and location changes in peripheral immune organs induced by PRRSV infection and reinfection. Our results show that PRRSV reinfection induced higher levels of IL-4 mRNA and protein expression in the peripheral immune organs (e.g., lymph node and spleen) and peripheral blood compared with PRRSV primary infection. Importantly, we found that, following PRRSV reinfection, an obvious large-scale migration of IL-4 occurred in the lymph nodes. During PRRSV primary infection, IL-4 was mainly concentrated around the lymphoid follicles and paracortical regions of the lymph node and also located in the marginal area and periarterial lymphatic sheath region of the spleen. During PRRSV reinfection, the now abundant IL-4 gathered into the lymphoid follicles of the lymph node and spleen. Notably, IL-4 changed its location state from scattered and sparse during primary infection to clinging to B lymphocytes in the lymphoid follicles during reinfection. During reinfection, IL-4 was often co-localized with T and B lymphocytes; furthermore, the percentages of several T lymphocyte subsets, N protein-specific antibody levels, and viral load in the peripheral blood or lymph tissues underwent remarkable variation. Another important finding of this study was that the numbers of B lymphocytes and T lymphocytes in the lymphoid nodes were significantly reduced after PRRSV infection or reinfection, presumably due to PRRSV-induced acute bone marrow failure and autophagy in thymic epithelial cells. This study revealed the characteristics of IL-4 migration and distribution in the peripheral lymph organs induced by PRRSV reinfection and provides valuable clues for further exploration of the interactions between IL-4, B lymphocytes, and T lymphocytes during PRRSV infection and reinfection.

Astragalus protects PC12 cells from 6-hydroxydopamine-induced neuronal damage: A serum pharmacological study.

Accumulating evidence has already indicated that traditional Chinese medicine (TCM) possesses tremendous potential for treating neurodegenerative diseases. Astragalus, also named Huangqi, is a famous traditional medical herb that can be applied to treat cerebral ischemia and prevent neuronal degeneration. Nevertheless, the underlying mechanisms remain largely unexplored. In the present study, Astragalus-containing serum (ASMES) was prepared and added into the culture medium of PC12 cells to explore its neuroprotective effect on 6-hydroxydopamine (6-OHDA)-caused neuronal toxicity. Our data showed that ASMES significantly ameliorated the cellular viability of cultured PC12 cells against the neurotoxicity induced by 6-OHDA (P < 0.05). Moreover, ASMES significantly decreased the cell apoptosis triggered by 6-OHDA (P < 0.01). Furthermore, 2',7'-dichlorofluorescin diacetate assay was performed to detect the changes in oxidative stress, and we showed that 6-OHDA elevated the production of reactive oxygen species (ROS), whereas ASMES significantly reversed these changes (P < 0.01). Besides, mitochondrial membrane potential (MMP) assay showed that ASMES could restore 6-OHDA-damaged MMP in cultured PC12 cells (P < 0.05). In conclusion, Astragalus could protect PC12 cells from 6-OHDA-caused neuronal toxicity, and possibly, the ROS-mediated apoptotic pathway participated in this process. Collectively, our findings provided valuable insights into the potential in treatment of neurodegenerative diseases.

Hepatocarcinoma cell-derived hepatoma-derived growth factor (HDGF) induces regulatory T cells.

BACKGROUND AND AIMS: It is suggested that regulatory immune cells play a critical role in cancer cell growth by facilitating cancer cells to escape from the immune surveillance. The generation of the immune regulatory cells in cancer has not been fully understood yet. This study aims to investigate the role of the hepatoma-derived growth factor (HDGF) in the generation of regulatory T cells (Treg). METHODS: CCL-9.1 cells (A mouse hepatoma cell line), were cultured. The expression of HDGF in CCL-9.1 cells was assessed by quantitative RT-PCR and Western blotting. The generation of Foxp3(+) T cells was assessed by cell culture and flow cytometry. The immune suppressor function of the Foxp3(+) T cells on CD8(+) T cell activities was assessed by the carboxyfluorescein succinimidyl ester (CFSE)-dilution assay and enzyme-linked immunosorbent assay. RESULTS: The results showed that exposure to PolyIC markedly increased the expression of HDGF in CCL-9.1 cells. Coculture of CCL-9.1 cells and CD4(+) CD25(-) T cells in the presence of PolyIC generated the Forkhead box protein (Foxp)3(+) T cells. The exposure to HDGF increased the expression of Foxp3 and decreased the expression of GATA3 in CD4(+) T cells. After activation, the Foxp3(+) T cells suppressed the CD8(+) T cell proliferation and the release of the cytotoxic cytokines. CONCLUSIONS: Liver cancer cell-derived HDGF can induce Foxp3(+) T cells; the latter has the immune suppressor functions on CD8(+) T cell activities.

X-ray irradiation promotes apoptosis of hippocampal neurons through up-regulation of Cdk5 and p25.

BACKGROUND: Cranial radiation therapy has been used for the treatment of primary and metastatic brain tumors. A prominent feature of brain injury induced by the radiation therapy is hippocampal dysfunction, characterized by a decline in memory. Cdk5 plays an important role in memory formation. Abnormal Cdk5 activity is associated with neuronal apoptosis induced by neurotoxic stimuli. However, the roles of Cdk5 in hippocampal apoptosis in response to X-ray irradiation have not been explored. METHODS: The expression of Cdk5 activators, p35 and p25, in hippocampal neurons was tested in both in vivo animal and in vitro couture after X-ray irradiation. RESULTS: After X-ray irradiation at 20 Gy and 30 Gy in rats, the number of hippocampal neuronal pyknosis was increased, but the number of hippocampal neuron was decreased, in the hippocampal CA1 region of rats. In these animals undergone with X-ray irradiation, the expression of p35 was significantly down-regulated, but it was up-regulated in p25. These opposite expressions were also shown in the primary cultured hippocampal neurons with 30 Gy irradiation. The apoptosis induced by X-ray irradiation were significantly prevented by the pretreatment of Cdk5 inhibitor, roscovitine, in both in vivo and in vitro settings. CONCLUSIONS: X-ray irradiation resulted in a hippocampal neuronal apoptosis through up-regulation of p25, the Cdk5 activator. Hyperactivity of Cdk5 was involved in the pathogenesis of X-ray irradiation-induced hippocampal neuronal apoptosis. Blockade of Cdk5 signal pathway effectively protected neurons from the irradiation-induced brain injury.

Akt promotes irradiation-induced regulatory T-cell survival in hepatocellular carcinoma.

BACKGROUND: Radiotherapy is an efficient remedy in the treatment of hepatocellular carcinoma (Hca); however, some cancer cells can still survive from the radiation and the therapeutic effect is to be improved. Regulatory T cell (Tregs)-induced tumor tolerance and Akt expression play important roles in the tumor survival. This study aims to elucidate the role of radiation induces Akt expression in Tregs. METHODS: A rat Hca model was developed. Hca tissue was collected from the rats with or without radiotherapy. The frequency of Treg and apoptotic Treg in Hca tissue was assessed by flow cytometry. A cell culture model was used to investigate the mechanism by which the tumor-infiltrating Tregs survive from irradiation. RESULTS: After radiotherapy, the frequency of Treg was increased in Hca, the frequency of apoptotic Tregs was decreased and the expression of Akt was increased in the remaining Tregs. The results were reproduced in vitro with a cell culture model. The addition of Akt inhibitor blocked the irradiation-induced Treg survival. Tregs with high levels of Akt still preserve the immune suppressor function. CONCLUSIONS: Akt plays an important role in the radiation-induced tumor-infiltrating Treg survival in Hca.

Cytokine tumor necrosis factor alpha induces intestinal epithelial barrier dysfunction.

BACKGROUND AND AIMS: Epithelial barrier dysfunction is involved in a number of diseases in the body. The mechanism is to be further understood. The present study aimed to investigate the role of one of the common microbial products, flagellin (FGN), in the induction of intestinal epithelial barrier dysfunction. METHODS: We collected the colon epithelium specimens from 40 patients with ulcerative colitis (UC), 40 patients with Crohn's disease (CD) and 40 healthy volunteers. The expression of toll like receptors (TLR)5 of the specimens was assessed by RT-PCR and western blotting. The expression of tumor necrosis factor alpha (TNFα) and its role in compromising the barrier function in the intestinal epithelial cells, T84 cells, were observed by a cell culture model. RESULTS: The results showed that the expression of TLR5 was observed in the colon epithelium of healthy subjects that was increased in UC patients and further increased in CD patients. Treating T84 cells with FGN increased the expression of TNFα in the cells that caused the T84 cell apoptosis as well as compromised the T84 monolayer barrier function, which could be prevented by knocking down the gene of TNFα in T84 cells. CONCLUSIONS: We conclude that the human colon epithelial cells express detectable TLR5 that is increased in patients with CD and UC. The exposure to FGN can increase the expression of TNFα that further compromises the intestinal epithelial barrier function.

[PKC isoform selectivity and radiation-induced apoptosis of HepG2 cells].

OBJECTIVE: To investigate the expressions of protein kinase C (PKC) isoforms in X-ray-exposed HepG2 cells and identify the PKC isoforms that induce radioresistance in HepG2 cells. METHODS: Cultured HepG2 cells were divided into control group and 6 Gy radiation group for corresponding treatments. The fluorescence intensity (FI) and the percentage of positive cells were determined using flow cytometry. RESULTS: The FI of PKCalpha and PKCdelta were 2.28 and 5.05 in the radiation group, respectively, significantly higher than those in the control group (P<0.05). The percentages of PKCalpha- and PKCdelta -positive cells were significantly higher in the radiation group than in the control group (P<0.05). The FI and the percentages of PKC zeta, gamma, epsilon, zeta positive cells were rather low and showed no significant differences between the two groups (P>0.05); PKCbeta expression was not detected in the two groups of cells. The apoptosis rates of the control and radiation groups were 1.73% and 20.90%, respectively. CONCLUSION: PKCalpha and PKCdelta may be involved in protecting HepG2 cells from radiation-induced apoptosis.

Antitumor effects of recombinant human interleukin-6 on mouse bladder carcinoma through Fas-mediated apoptosis.

PURPOSE: An apoptosis-inducing therapy is gradually becoming a new strategy for cancer treatment. The aim of this study was to investigate the mechanism of growth-inhibitory effects of recombinant human interleukin-6 (rhIL-6) on bladder tumor-bearing T739 mice in vivo. METHODS: Murine bladder transitional carcinoma cells (BTT739) were inoculated subcutaneously into T739 mice as a tumor model for evaluating the antitumor effects of rhIL-6. Then the mice were divided randomly into 5 groups: A, B, C, D and E. Different doses (0, 2, 4, 8 x 10(6) IU/kg body weight) of rhIL-6 were injected intraperitoneally twice per day and administered for 14 days, and 1 mg/kg/d mitomycin-C(MMC) was used as control. Tumor size was measured and determined as the mean of the largest diameter and the diameter at right angle. Animals were killed by CO(2) inhalation on the 15th day after tumor cell inoculation. Then, tumors were removed, weighed and collected. The tumor growth inhibition rate of rhIL-6 was calculated. The morphological characteristic changes of tumor cells were observed under electron microscope, and cell cycle analysis was determined by flow cytometry. The expressions of Fas, FasL and Bcl-2 protein on tumor cells were qualitatively detected by immunofluorescence cell staining, and their relative contents (rate of positive cells, RPC) were quantitatively determined with flow cytometry. RESULTS: rhIL-6 could inhibit bladder tumor growth in a dose-dependent manner in vivo. The tumor growth-inhibitory rates of 2, 4, 8 x 10(6) IU/kg rhIL-6 and 1 mg/kg MMC were 11.8, 39.5, 39.7 and 68.8%, respectively. Flow cytometry results showed that a hypodiploid peak before G1 phase could be found in tumor cells treated with rhIL-6. Moreover, the cells treated with rhIL-6 displayed disappearance of nucleoli, chromatin gathering under the nuclear membrane in mass or ring-shape under transmission electron microscopy. The rates of Fas, FasL protein-positive cells estimated by flow cytometry in rhIL-6-treated mice were (12.57 +/- 0.83) and (20.1 +/- 0.87) %, respectively, significantly higher than that (4.66 +/- 0.17) and (14.1 +/- 0.83) % in control mice (P < 0.01). There was no significant difference in the rate of Bcl-2 protein-positive cells between the mice in these two groups (P > 0.05). CONCLUSIONS: rhIL-6 had obvious antitumor effects on mouse bladder carcinoma in vivo, and the Fas signaling pathway might play an important role in rhIL-6-induced bladder carcinoma cell apoptosis.

[The significance and function of IFN-gamma on the changes of peripheral blood platelet count during tumor-rejection induced by a low dose of melphalan in C57BL/6 mice].

AIM: To investigate the significance and function of IFN-gamma on the changes of peripheral blood platelet count during tumor-rejection induced by a low dose of melphalan in C57BL/6 mice. METHODS: Mouse tumor rejection model induced by a single dose of melphalan was used in this experiment. Different gene-type tumor-bearing mice (IFN-gamma(+/-) and IFN-gamma(-/-)), which had the same genetic background of C57BL/6, were treated intraperitoneally with melphalan (7.5 mg/kg). Tumor size was observed and recorded every one to three days in these different gene-type mice subsequently. Blood samples were obtained from orbital venous sinus on different days before and after melphalan treatment, and then complete blood counts were performed. The function of IFN-gamma on the efficacy of chemotherapy and the changes of blood platelet count in IFN-gamma(+/-) and IFN-gamma(-/-) mice after melphalan treatment was analyzed. RESULTS: There was no significant difference in tumor sizes and blood platelet count between IFN-gamma(-/-) and IFN-gamma(+/-) mice (P>0.05). On the first day after melphalan (7.5 mg/kg) treatment, there were no significant changes in tumor sizes between mice in these two groups (P>0.05). Tumors shrank a little in IFN-gamma(-/-) mice and then grew gradually. Tumors relapsed in 2 w after melphalan injection in all IFN-gamma(-/-) mice, while tumor volumes decreased progressively and tumor cured at last in IFN-gamma(+/-) mice. The number of blood PLT in IFN-gamma(+/-) mice increased to (1935+/-378) x 10(9)/L 6 h after melphalan treatment, significantly higher than before (P<0.01); While in IFN-gamma(-/-) mice it was (1183+/-186) x 10(9)/L 6 h after melphalan treatment, no obvious increase than before. There was significant difference in blood PLT 6 h after melphalan treatment between IFN-gamma(+/-) and IFN-gamma(-/-) mice (P<0.01). Later, the numbers of blood PLT in IFN-gamma(+/-) mice decreased gradually and it dropped to normal (1158+/-270) x 10(9)/L on 11th day after melphalan treatment (P>0.05); While it sustained in normal range in IFN-gamma(-/-) mice. There was no significant difference in blood platelet count between IFN-gamma(-/-) and IFN-gamma(+/-) mice. CONCLUSION: Peripheral blood platelet count increased on the first day after melphalan treatment and tumors cured in IFN-gamma(+/-) mice; While tumors relapsed and there is no increase in blood platelet count on the first day after melphalan treatment in IFN-gamma(-/-) mice. These data indicated that the increase of blood PLT count was related to the function of IFN-gamma in tumor-bearing mice in vivo during tumor rejection induced by a low dose of melphalan.

[Changes and significance of peripheral blood count in tumor rejection induced by a low dose of melphalan in C57BL/6 mice].

AIM: To investigate the relationship between changes of peripheral blood counts and tumor rejection induced by a low dose of melphalan in C57BL/6 mice. METHODS: Mouse lymphoma EL4 cells were inoculated subcutaneously into wild type C57BL/6 mice. Twelve days later, 7.5 mg/kg melphalan were administered intraperitoneally and the same volume of Normal Saline as control. Tumor sizes were observed and recorded subsequently. Blood samples were obtained from orbital venous sinus on different days before and after melphalan treatment, and then complete blood counts were performed and the relationship between the alterations of blood counts and tumor shrinkage after melphalan treatment was analyzed. RESULTS: Tumor sizes decreased and tumors disappeared after 7.5 mg/kg melphalan treatment; while tumors grow continuously in control mice. The number of WBC was increased a little (10.6 + or - 2.3) x 10(9)/L 6 h after melphalan treatment, but there was no significant difference with mice before melphalan injection (9.8 + or - 0.32) x 10(9)/L (P>0.05); The number of WBC decreased significantly at 4(th) day after melphalan treatment (P<0.01); Later it increased a little, but at 28(th); day after melphalan it still obviously lower than that of the normal (P<0.01). Hemoglobin (Hb) concentration decreased from (132 + or - 7) g/L before melphalan treatment to (110 + or - 14) g/L at 6 h after melphalan treatment (P<0.05). Later, the amount of Hb was decreasing and at 7th day it got to its lowest point (96 + or - 5) g/L. It increased gradually back to normal in 2 weeks after melphalan treatment. The platelet count increased to (1502 + or - 142) x 10(9)/L 6 h after melphalan treatment, significantly higher that that (914 + or - 322) x 10(9)/L before melphalan injection (P<0.01). It maintained at a high level for one week and it recovered back to normal level at 28(th) day after melphalan treatment. CONCLUSION: Tumor shrinkage after melphalan treatment was not related to the decreased number of WBC or RBC, but correlated with the increased number of platelet in 10 days after melphalan treatment.

[A comparison of curative effects of percutaneous nephrostomy and open surgery in the management of postrenal acute renal failure].

OBJECTIVE: To investigate the effects and clinical value of percutaneous nephrostomy (PCN) in the management of postrenal acute renal failure (PARF). METHODS: The clinical data of 40 cases of PARF for the treatment of PCN and 20 cases with open surgery were retrospectively analyzed. RESULTS: The success rate of PCN was 100%, renal function of all patients was restored to normal range after 2-7 days of PCN, in whom 30 patients recovered. In 10 patients nephrostomy was prolonged, among them 2 patients had recurrent abdominal tumors, and 8 patients had cervical cancer in late phase. There was no death, and no complications except hematuria. In the open surgery group, renal function of 19 cases recovered to normal range after 2-7 days of drainage. Lung infection occurred in 3 patients after operation, and they recovered with antibiotic therapy. One patient died of multiple organ dysfunction failure (MOF). CONCLUSION: For PARF, PCN is preferable because of minimal trauma, less blood loss, as well as rapid recovery and better effect on recovery of renal function.

[Changes and significance of peripheral blood platelet count in tumor shrinkage induced by a low dose of CTX in T739 mice].

AIM: To establish a mouse model for BTT739 tumor-bearing mice cured by a low dose of cyclophosphamide (CTX). And then to observe the dynamic changes and significance of peripheral blood counts especially blood platelet count during tumor shrinkage induced by a low dose of CTX in T739 mice. METHODS: Mouse bladder carcinoma tissues were inoculated subcutaneously into T739 mice. Seven days later, different doses of CTX or the same volume of NS were administered intraperitoneally to treat these tumor-bearing T739 mice. Tumor sizes were observed and recorded subsequently to find out the minimal dose of CTX that could cure most of these tumor-bearing mice. Then another 12 tumor-bearing mice were randomly divided into 15 mg/kg CTX treatment group and control group. Blood samples were obtained from orbital venous sinus on different times after CTX treatment. Complete blood counts were performed and the relationship between peripheral blood platelet counts and tumor shrinkage was analyzed. RESULTS: Within 2 weeks after CTX treatment, the speed of tumor shrinkage had a positive relationship with the dose of CTX used; but the survival rate of the tumor-bearing mice had a negative relationship with the dose of CTX used in 2 months after CTX treatment. 15 mg/kg CTX could cure most of the tumor bearing mice, while it had no remarkably inhibitive effects on peripheral blood cells. The perpherial platelet count increased to (1483.4+/-184.4)x10(9)/L in mice 6 h after CTX treatment. There was significant difference compared with that in mice of control group (1086.6+/-81.0)x10(9)/L (P<0.01). During the 2nd to 14th day after CTX treatment, there was no obvious difference in the platelet count between treatment group and control group (P>0.05). CONCLUSION: CTX 15 mg/kg could cure most of bladder tumor-bearing T739 mice. The transient increase of the peripheral platelet count in 6 h after CTX treatment may relate to the antitumor effects of CTX.

[Relationships between tumor shrinkage and peripheral blood cell changes during tumor-rejection induced by a high dose of 5-FU in C57BL/6 mice].

AIM: To investigate the relationship between the alterations of complete blood counts and tumor shrinkage during tumor rejection induced by a high dose of 5-FU in C57BL/6 mice. METHODS: Wild type C57BL/6 tumor-bearing mice were treated with different doses of 5-FU intraperitoneally. 75 mg/kg 5-FU was the minimal effective dose of 5-FU that could cure the tumor-bearing mice. Then another 6 tumor-bearing mice were treated intraperitoneally with 5-FU (75 mg/kg). Blood samples were obtained from orbital venous sinus on different days before and after 5-FU treatment, and then complete blood counts were performed and the relationship between the alterations of blood counts and tumor shrinkage after 5-FU treatment was analyzed. RESULTS: Tumor sizes decreased steadily and tumors disappeared within the first week after 5-FU treatment; and at the same time 75 mg/kg 5-FU also had side effects on peripherial blood cells. The number of WBC significantly decreased from the first day after 5-FU treatment (P<0.001). But during the 7 th to 15 th day the number of WBC rebounced back to normal level (P>0.05). Later it decreased again and it couldn't recover back to normal level at the 28th day after 5-FU treatment (P<0.01). The concentration of Hb decreased at the first day and lasted for 2 weeks (P<0.01). It increased gradually back to normal in 2 weeks after 5-FU treatment. The inhibitory effect of 5-FU on platelets count was not obvious. The platelet count increased significantly at the first and at the 11th day after 5-FU treatment respectively (P<0.01). CONCLUSION: Tumor shrinkage after 5-FU treatment is not related to the decreased number of WBC or RBC, but correlated with the increased number of platelet at the first day after 5-FU treatment.

[Study of the immunological mechanism of anti-tumor effects of 5-FU by establishing EL4 tumor-bearing mouse models].

AIM: To investigate the immunological mechanism of anti-tumor effect of 5-FU by establishing lymphoma EL4 tumor-bearing mouse models in wild type C57BL/6 mice and nude C57BL/6 mice, respectively. METHODS: The mouse lymphoma EL4 cells were inoculated subcutaneously into wild type C57BL/6 mice (immune-competent mice). Twelve days later, 5-FU of different doses was administered intraperitoneally to treat these wild type C57BL/6 tumor-bearing mice. The size of tumors in the wild type C57BL/6 mice was observed and recorded to explore the minimal dose of 5-FU that could cure the tumor-bearing mice. Then the same amount of EL4 tumor cells was inoculated subcutaneously into wild type C57BL/6 mice and nude C57BL/6 mice (T cell-deficient mice) simultaneously, which had the same genetic background of C57BL/6. Twelve days later, 5-FU of the minimal dose was given intraperitoneally to treat both the wild type and nude C57BL/6 tumor-bearing mice. The size of tumors in the two different types of mice was observed and recorded. RESULTS: A single dose of 5-FU (75 mg/kg) cured both the EL4 tumor-bearing wild type C57BL/6 mice and the EL4 tumor-bearing nude C57BL/6 mice in the first week. Two weeks after 5-FU treatment, all of the nude mice died of tumor relapse while most of the wild type C57BL/6 mice were fully recovered. CONCLUSION: A single dose of 5-FU has marked anti-tumor effects on lymphoma EL4 tumor-bearing C57BL/6 mice with or without T lymphocytes. The relapse of tumors after 5-FU treatment might be related to the function of T lymphocytes.

[Relationship between sensitivity of tumor cells to chemotherapeutic agent in vivo and in vitro: experiment with mouse lymphoma cells].

OBJECTIVE: To study the relationship of the sensitivity of tumor cells to chemotherapeutic agent between in vivo and in vitro. METHODS: Mouse lymphoma cells of the line E14 were cultured and melphalan resistant EL4 cell line (EL4/melphalan) was established by culturing EL4 cells with continuous low-concentration and intermittent gradually-increasing-concentration of melphalan in vitro. MTT assay was used to evaluate the drug sensitivity and the resistance index of the EL4/melphalan cells to melphalan was calculated. EL4/melphalan and EL4 cells of the concentration of 5 x 10(8)/L were inoculated separately into 20 C57BL/6 mice subcutaneously. 12 days later, the EL4 and EL4/melphalan tumor-bearing mice were randomly divided into 2 groups respectively, 5 mice in each group. Treatment groups were given 7.5 mg/kg melphalan intraperitoneally, and control groups were given the same volume of normal saline. The tumor size was observed every other day. RESULTS: Compared with the EL4 cells, the EL4/melphalan cells had no obvious changes morphologically. They could grow in RPMI 1640 medium containing 5 mg/ml melphalan. The resistance index was 2.87 against melphalan. After the treatment of melphalan of the dose 7.5 mg/kg, the tumor sizes of the treatment groups and control groups inoculated with both EL4 cells and the EL4/melphalan cells gradually decreased at the similar speed, and about one week later all tumors disappeared. However, the tumors of the control groups grew progressively and all the mice died at last. CONCLUSION: The chemotherapeutic effects of tumors in vivo have nothing to do with the effects of the chemotherapeutic agents on tumor cells in vitro. The tumor cells resistant to melphalan in vitro remain sensitive to the drug in vivo.

[Relationship between TNFalpha and tumor rejection induced by a single dose of melphalan in C57BL/6 mice].

AIM: To investigate the relationship between TNFalpha and tumor rejection induced by a single dose of melphalan in C57BL/6 mice. METHODS: Different gene type mice (TNFR1(+/+), TNFR1(+/-) and TNFR1(-/-)) with the same genetic background of C57BL/6 were used in this experiment. Murine lymphoma EL4 cells were inoculated subcutaneously into the different gene type mice simultaneously. Twelve days later, 7.5 mg/kg melphalan was used intraperitoneally to treat the tumor-bearing mice with TNFR1(+/+), TNFR1(+/-) and TNFR1(-/-). The tumors in the different gene type mice were observed and recorded every one to three day. RESULTS: After the treatment of 7.5 mg/kg melphalan during the first week, the tumors in the different gene type mice shrank at a similar rate. In the following 2 months, the tumors in the TNFR1(+/+) and TNFR1(+/-) C57BL/6 mice gradually shrank and were cured but most tumors in the TNFR1(-/-) C57BL/6 mice relapsed after melphalan treatment. CONCLUSION: TNFalpha plays an important role in melphalan-induced tumor rejection. The anti-tumor effect of melphalan has no relationship with the expression of tumor necrosis factor 1 in tumor-bearing mice. TNFR1 is required to prevent or avoid the relapse of tumors in mice instead of tumor cells.

[Relationship between anti-tumor effects of melphalan and IFN-gamma].

AIM: To investigate the relationship between IFN-gamma and anti-tumor effects of melphalan in vivo. METHODS: Different gene-type mice (IFN-gamma(+/+), IFN-gamma(+/-) and IFN-gamma(-/-)), which had the same genetic background of C57BL/6, were used in this experiment. Murine lymphoma EL4 cells were inoculated subcutaneously into different gene-type mice simultaneously. Twelve days later, 7.5 mg/kg melphalan was used intraperitoneally to treat all these IFN-gamma(+/+), IFN-gamma(+/-) and IFN-gamma(-/-) tumor-bearing mice. Tumor size was observed and recorded every one to three days in these different gene-type mice subsequently. RESULTS: After melphalan (7.5 mg/kg) treatment, tumor size decreased at a similar rate in IFN-gamma(-/-), IFN-gamma(+/-) and IFN-gamma(+/+) mice within the first 3 d. Tumors shrank further or completely disappeared in most of IFN-gamma(+/-) and IFN-gamma(+/+) mice, whereas tumors grew gradually in all IFN-gamma(-/-) mice. CONCLUSION: 7.5 mg/kg melphalan has obvious anti-tumor effects on tumor-bearing IFN-gamma(+/+) and IFN-gamma(+/-) mice, but little effects on IFN-gamma(-/-) mice. These data suggest that IFN-gamma is required for the anti-tumor effects of melphalan on tumor-bearing mice in vivo.

[Establishment of EL4 tumor-bearing mouse models and investigation on immunological mechanisms of anti-tumor effect of melphalan].

AIM: To establish mouse lymphoma EL4 tumor-bearing mouse models in wild type C57BL/6 mice and nude C57BL/6 mice respectively, and to further investigate the immunological mechanisms of anti-tumor effect of melphalan. METHODS: Mouse lymphoma EL4 cells were inoculated subcutaneously into wild type C57BL/6 mice (immune-competent mice). Twelve days later, melphalan of different doses were administered intraperitoneally to treat these wild type C57BL/6 tuomr-bearing mice. Tumor sizes were observed and recorded subsequently to find out the minimal dose of melphalan that could cure the tuomr-bearing mice. Then the same amount of EL4 tumor cells were inoculated subcutaneously into wild type C57BL/6 mice and nude C57BL/6 mice (T cell-deficient mice) simultaneously, which had the same genetic background of C57BL/6. Twelve days later, melphalan of the minimal dose was given intraperitoneally to treat both the wild type and nude C57BL/6 tuomr-bearing mice. Tumor sizes were observed and recorded in these two different types of mice subsequently. RESULTS: A single dose of melphalan (7.5 mg/kg) could cure EL4 tumor-bearing wild type C57BL/6 mice, but could not induce tumor regression in EL4 tumor-bearing nude C57BL/6 mice. CONCLUSION: A single dose of melphalan has obvious anti-tumor effect on mouse lymphoma EL4 tumor-bearing wild type C57BL/6mice, which requires the involvement of T lymphocytes in the host probably related to their killing functions.

Correlation of multidrug resistance with up-regulation of protein kinase C expression in KBV200 cells.

OBJECTIVE: To investigate protein kinase C (PKC) expression and its association with multidrug resistance (MDR) in KBV200 cells. METHODS: KBV200 cells were preincubated with PKC activator phorbol-12-myristate-13-acetate (PMA, 200 nmol/L) and PKC activity was assayed by measurement of peptide substrate (32)P incorporation from [gamma-(32)P]ATP, with the cells without PMA preincubation serving as the control. Western blotting was performed for assessing the expression of PKC isoform, and the cell inhibition rate was evaluated by MTT assay. RESULTS: PMA preincubation of the cells significantly enhanced the activity of the total PKC and the membrane fraction, but lowered the PKC activity of the cytosol fraction, as compared with the cells without PMA treatment (P<0.01). PKC-alpha expression was upregulated in the membrane fraction and down-regulated in the cytosol fraction in KBV200 cells after PMA preincubation. PKCbeta expression was slightly elevated in the cytosol fraction but exhibited no obvious changes in the membrane fraction after PMA pretreatment of the cells. The values of IC(50) of vincristine and adriamycin in PMA-treated cells were increased to 2275.5 nmol/L and 233.25 nmol/L, respectively (P<0.01). CONCLUSION: PMA can increase the multidrug resistance of KBV200 cells, which suggests the possible involvement of PKC in the mechanism of multidrug resistance of tumor cells.

[Toxicity attenuation and efficacy potentiation effects of sijunzi decoction on bladder carcinoma treated by chemotherapy in mice].

OBJECTIVE: To investigate the toxicity attenuation and efficacy potentiation effects of Sijunzi decoction (SJZD) on bladder carcinoma treated by chemotherapy in mice. METHODS: T739 mice were randomly divided into 8 groups after subcutaneous inoculation of bladder carcinoma cells, the control group (A); two mitomycin C (MMC) group, treated with MMC of routine dosage (B) and low-dosage (C) respectively; three SJZD groups, treated with SJZD of high (D), medium (E) and low-dosage (F) respectively; and two combined treatment groups, treated with SJZD of high-dosage + MMC of routine dosage(G) and SJZD of high-dosage + MMC of low-dosage(H). The medication was begun at 24 hrs after inoculation. The tumor inhibitory rate, activity of peritoneal macrophages after 14 days of treatment and change of peripheral white blood cells after 7 days of treatment were determined and the survival time of mice was observed. RESULTS: The survival time of mice in Group D was significantly higher than that in Group A (P < 0.05), while those in Group E and F showed insignificant difference as compared with those in Group A (P > 0.05). The highest tumor inhibitory rate was shown in Group B, but the survival time in that group showed no significant difference as compared to those in Group A (P > 0.05). The longest survival time (32.7 +/- 1.3 days) was shown in Group H, which was obviously different to that in other groups (P < 0.05). And the leukocyte counts and macrophage activity in Group H were better than those in Group B, C and G (P < 0.05), except that the tumor inhibitory rate was significantly lower than that in Group B, C and G (P < 0.05). CONCLUSION: Combined chemotherapy of SJZD with low dosage MMC has definite effect in inhibiting tumor growth in mice with bladder carcinoma, displaying special effects of toxicity attenuation and efficacy potentiation.