高浓度葡萄糖对胰岛细胞的IRS2表达及细胞凋亡的影响

目的 探讨高浓度葡萄糖条件下胰岛细胞胰岛素受体底物2(IRS2)和Bax基因表达和激活情况以及对诱导胰岛细胞凋亡的影响.方法 将小鼠胰腺进行分离纯化所得的胰岛细胞进行体外培养,按培养液里葡萄糖浓度不同分为G1组(5.6 mmol/L)、G2组(7.8 mmol/L)、G3组(11.1 mmol/L)、G4组(16.7 mmol/L)、G5组(22.2 mmol/L)及G6组(27.6mmol/L).细胞培养至72h后,采用放射免疫法检测各组胰岛细胞胰岛素分泌水平、免疫细胞组织化学法检测IRS2表达、免疫荧光法检测细胞Bax激活和细胞核Hoechst33342染色检测细胞凋亡情况.结果 当葡萄糖浓度在5.6～11.1 mmol/L时,胰岛素分泌水平升高,IRS2表达和Bax激活分别呈进行性增加,但此时细胞凋亡率无明显改变.随着葡萄糖浓度升高至超过16.7mmol/L时,IRS2表达逐渐减少,胰岛素分泌量明显降低,而Bax激活则逐渐增强,胰岛细胞凋亡率呈明显增加趋势.结论 高浓度葡萄糖可以导致胰岛细胞IRS2表达下降,胰岛素分泌量下降;同时Bax激活增强,胰岛细胞凋亡率也明显增加.说明IRS2表达下降与凋亡相关蛋白Bax激活及其胰岛细胞凋亡可能存在必然的联系,而且IRS2表达下降可能是胰岛素分泌减少的原因之一.增强胰岛素信号传导通路中IRS2蛋白的表达可能对于保护胰岛细胞有重要作用.

Abstract：

Objective To investigate the role of insulin receptor substrate 2(IRS2) and Bax on mouse islet cell apoptosis in the presence of high glucose in vitro.Methods The pancreatic islet cells were isolated from Kunming mice and divided into 6 groups(G1-G6 groups)for a 72-h culture in the media containing different concentrations of glucose(5.6,7.8,11.1,16.7,22.2,and 27.6 mmol/L,respectively).Insulin secretion by the cells was evaluated by radioimmunoassay,and the expressions of IRS2 and Bax were detected using immunocytochemistry and immunofluorescence assay,respectively.Hoechst33342 staining was employed to observe the cell apoptosis. Results Exposure to 5.6-11.1 mmol/L glucose resulted in increased insulin secretion and progressive elevation of IRS2 and Bax expression,whereas the cell apoptosis underwent no obvious changes.In the presence of glucose above 16.7 mmol/L,the percentages of apoptotic islet cells increased with glucose concentration,but insulin secretion and IRS2 expression decreased;Bax expression significantly increased in the presence of high-concentration glucose.Conclusion Prolonged exposure of mouse islet cells to high glucose induces apoptosis and impairs insulin secretion of the cells.Decreased IRS2 expression and increased Bax expression may play an important role in the glucotoxicity in mouse islet cells.     

Expression of EPO Receptor in Pancreatic Cells and Its Effect on Cell Apoptosis

In order to explore the expression of erythropoietin receptor （EPOR） in pancreatic cell line NIT-1 and its effect on cell apoptosis after binding with erythropoietin （EPO）, NIT-1 cells were cultured and expanded. The expression of EPOR was detected using electrophoresis. NIT-1 apoptosis was induced by cytokines and their effects on cell apoptosis and cell insulin secretion were assayed after binding of EPO to EPOR. The results showed that EPOR was expressed in NIT-1 cells. Recombinant human EPO （rHuEPO） had no effect on cell apoptosis but significantly inhibited apoptosis induced by cytokines, rHuEPO had no effect on cell insulin secretion but significantly improved insulin secretion inhibited by cytokines. From these findings, it was concluded that EPOR was expressed in NIT- 1 cells and EPO could protect NIT- 1 cells from apoptosis induced by cytokines.     

Expression of NF-κB in hRPE Cells Stimulated by PDTC and IL-1β

The constitutive expression of nuclear-factor-κB (NF-κB) in human pigment epithelial (hRPE) cells cultivated in vitro and the possible changes when incubated with PDTC and IL-I were investigated. The synchronized hRPE cells in vitro were divided into two groups. In nonPDTC group, hRPE cells were exposed respectively to IL-1β and NS (for detecting the constitutive expressions of NF-κB in hRPE cells) ; In PDTC group, PDTC-pretreated hRPE cells were exposed respectively to IL-1β?Aand NS. (for detecting the constitutive expression of NF-κB in PDTC-pretreated hRPE cells). The expression of NF-κB in hRPE cells in two groups was detected by immunofluorescence stain and flow cytometry. The results showed that the constitutive expression of NF-κB in hRPE cells in vitro was 8.05 %, and increased to 30.26 % by IL-1β. After PDTC pretreatment, the constitutive expression of NF-κB in hRPE cells was decreased to 3.74%, and 3.66 % by IL-l,respectively. It was concluded that the expressions of NF-κB in hRPE cells could be increased significantly by IL-1βand depressed effectively by PDTC. Also, PDTC could significantly inhibit the activation of NF-κB induced by IL-1β.     

Increased expression and activity of MMP-9 in C-reactive protein- induced human THP-1 mononuclear cells is related to activation of nuclear factor kappa-B

The relation between the expression and activity of MMP-9 in C-reactive protein （CRP）-induced human THP-1 mononuclear cells and the activation of nuclear factor kappa-B （NF-κB） was studied to investigate the possible role of CRP in plaque destabilization. Human THP-1 cells were incubated in the presence of CRP at 0 （control group）, 25, 50 and 100 μg/mL （CRP groups） for 24 h. In PDTC （a specific NF-κB inhibitor） group, the cells were pre-treated with PDTC at 10 μmol/L and then with 100 μg/mL CRP. The conditioned media （CM） and human THP-1 cells in different groups were harvested. MMP-9 expression in CM and human THP-1 cells was measured by ELISA and Western blotting. MMP-9 activity was assessed by fluorogenic substrates. The expression of NF-κB inhibitor α （IκB-α） and NF-κB p65 was detected by Western blotting and ELISA respectively. The results showed that CRP increased the expression and activity of MMP-9 in a dose-dependent manner in the human THP-1 cells. Western blotting revealed that IiB-α expression was decreased in the cells with the concentrations of CRP and ELISA demonstrated that NF-κB p65 expression in the CRP-induced cells was increased. After pre-treatment of the cells with PDTC at 10 μmol/L, the decrease in IκB-α expression and the increase in NF-κB p65 expression in the CRP-induced cells were inhibited, and the expression and activity of MMP-9 were lowered too. It is concluded that increased expression and activity of MMP-9 in CRP-induced human THP-1 cells may be associated with activation of NF-κB. Down-regulation of the expression and activity of MMP-9 may be a new treatment alternative for plaque stabilization by inhibiting the NF-κB activation.     

腺病毒介导的白细胞介素10基因转移对胰岛β细胞凋亡及胰岛素释放的影响

Objective To evaluate the efficacy of adenovirus vector-mediated murine interleukin-10 (mIL-10) gene transfer to rat beta cell-RINm5F cells in vitro and to explore the potential value of gene therapy in type 1 diabetes mellitus. Methods The recombinant adenovirus vector Ad-mIL-10 was constructed and transfected into RINm5F cells (Ad-mIL-10 group). Untransfected RINm5F cells and Ad-eGFP-transfected cells were used as controls. The expression of mIL-10 was examined by RT-PCR and Western blot The levels of IL-10 in supernatant were measured by enzyme-linked immunosorbent assay (ELISA). For a determination of insulin release, the cells were cultured with high glucose ( 16. 7mmol/L) for a 1 -hour co-incubation. Then radioimmunoassay was used to detect the level of insulin in supernatant After induction of IL-1β, the levels of nitric oxide (NO) and nitric oxide synthase ( NOS) were measured, the apoptosis of transfected cells was detected by Hoechst 33258 staining and Fas expression by flow cytometry. Results Both mRNA and protein of Ad-mIL-10 were successfully expressed in RINm5F cells. Expression of mIL-10 gene resulted in significant increases in insulin secretion in response to high glucose. Compared with uninfected control and Ad-eGFP infected group, Ad-mIL-10 infected group had decreased levels of NO and NOS induced by IL-lβ [ NO level ( nmol/106 cells): 52. 9 ± 3. 2 vs 227. 3 ± 26. 4, 235. 1 ±28.6, both P＜0.05; NOS level (U/106 cells): 9. 3 ±1.2 vs 29. 8 ±2.5, 30.5 ±2.8, both P ＜ 0. 05]. Furthermore, Ad-mIL-10 gene transfer led to a profound reduction of Fas-expressing islet cells under the induction of IL-1β. Fas-expressing islet cells in Ad-mIL-10 group were significantly lower than those in uninfected group and Ad-eGFP-transfected group (24. 6% ± 1.0% vs 33. 3% ± 5. 1% , 32. 6% ±1.1%) (P＜0.05).The apoptotic rates of Ad-mIL-10 group were lower in comparison with the other two groups (9.4%±1.1% vs 19.2%±2.2%,20.6%±2.3%,P＜0.05).Conclusions IL-10 gene transfer to islet beta cells may be beneficial in maintaining beta cells function,protecting islet cells from IL-1β-mediated apoptosis and promoting islet cells survival.It is a potential therapy for type 1 diabetes mellitus.     

Protection of human islets from induction of apoptosis and improved islet function with HO-1 gene transduction

Background Islet transplantation represents an ideal therapeutic approach for treatment of type 1 diabetes but islet function and regeneration may be influenced by necrosis or apoptosis induced by oxidative stress and other insults. Heme oxygenase-1 (HO-1) is the rate-limiting enzyme in the catabolism of heme into biliverdin, releasing free iron and carbon monoxide. It has also been reported to be an antioxidant enzyme which can improve the function of grafted islets by cytoprotection via free radical scavenging and apoptosis prevention. In the present study, we investigated whether transduction of HO-1 genes into human islets with an adenovirus vector has cytoprotective action on islets cultured in vitro and discuss this method of gene therapy for clinical islet transplantation.Methods Cadaveric pancreatic islets were isolated and purified in vitro. Transduction efficiency of islets was determined by infecting islets with adenovirus vector containing the enhanced green fluorescent protein gene (Ad-EGFP) at multiplicities of infection (MOI) of 2, 5, 10, or 20. Newly isolated islets were divided into three groups: EGFP group, islets transduced with Ad-EGFP using MOI＝20; HO-1 group, transduced with adenovirus vectors containing the human HO-1 gene using MOI＝20; and control group, mock transduced islets. Insulin release after glucose stimulation of the cell lines was determined by a radioimmunoassay kit and the stimulation index was calculated. Flow cytometry was used to detect apoptotic cells in the HO-1 group and in the control group after induction by recombinant human tumor necrosis factor-α (rTNFα) and cycloheximide (CHX) for 48 hours.Results Adenovirus vectors have a high efficiency of gene transduction into adult islet cells. Transduction of islets with the Ad-EGFP was most successful at MOI 20, at which MOI fluorescence was very intense on day 7 after transduction and EGFP was expressed in cultured islet cells for more than four weeks in vitro. The insulin release in the control group was (182.36±58.96) mIU/L after stimulation by high glucose media (16.7 mmol/L), while insulin release from the HO-1 group and the EGFP group were (270.09±89.37) mIU/L and (175.95±75.05) mIU/L respectively. Compared to the control group and the EGFP group, insulin release in the HO-1 group increased significantly (P＜0.05). After treatment with rTNFα and CHX the apoptotic ratio of islet cells was (63.09±10.86)% in the HO-1 group, significantly lower than (90.86±11.25)% in the control group (P<0.05).Conclusions Transduction of human islets with Ad-HO-1 can protect against TNF-α and CHX mediated cytotoxicity. The HO-1 gene also appears to facilitate insulin release from human islets. Transduction of donor islets with the adenovirus vector containing an HO-1 gene might have potential value in clinical islet transplantation.     

Effects of nuclear translocation of tissue transglutaminase and the release of cytochrome C on hepatocyte apoptosis

Objective To assess the effects of nuclear translocation of tissue transglutaminase (TTG) and the release of cytochrome C on hepatocyte apoptosis and to reveal the mechanism of signal transcluction of early apoptosis in injured hepatocytes.Methods Hepatocytes isolated from tissue transglutaminase gene knock-out mice and rats were stimulated with ethanol. Proteins from whole cell, cytoplasm and nuclei were extracted for determination of TTG activity by ^14C-putrescine incorporation. Distribution of TTG throughout the entire cell, as well as just nucleus was observed under a confocal scanning microscope. The amount of cytochrome C released from mitochonclria was determined by ELISA. Cell apoptosis was observed by fluorescent cytochemistry.Results TTG activity in whole cells and nuclei was significantly increased after the hepatocytes were treated with ethanol. Cytochrome C release was remarkably increased in the cells isolated from rat and wild-type mouse after treatment with ethanol but not in TTG gene knock-out mice. Cellular apoptosis appeared in hepatocytes isolated from rats and wild-type mice but not in the hepatocytes from TTG gene knock-out mice after stimulation with ethanol.Conclusions Increased TTG in hepatocytes can be translocated into the nucleus and promote release of mitochonclrial cytochrome C into the cytoplasm. Passing through a series of signal pathways, hepatocyte apoptosis is induced eventually.     

Effects of Antisense Oligodeoxynucleotide to Follicle-stimulating Hormone Receptor on the Cell Proliferation and Apoptosis in Cells Derived from Human Ovarian Mucinous Cystadenocarcinoma in Vitro

The human ovarian mucinous cystadenocarcinoma (hOMC) cells were co-cultured with antisense oligodeoxynucleotide (antisense ODN), nonsense ODN, and follicle-stimulating hormone (FSH) at different concentrations for the purpose of observing the effects of antisense ODN to FSH receptor (FSHR) on the proliferation and apoptosis of cultured hOMC cells in vitro. The inhibitory rates of growth were measured by using MTT method on the 2nd, 4th, 6th, 8th and 10th days after the interference of antisense ODN, nonsense ODN, and FSH, respectively. The apoptotic rates and the cell cycles were determined by means of flow cytometry, the apoptosis indexes were detected by us-ing TUNEL, and the expression of caspase-3 was measured by using SP immunohistochemistry. Compared with that in the control group, the proliferative activity of hOMC cells was increased ob-viously in FSH groups (P<0.05 or P<0.01), decreased distinctly in antisense ODN groups (P<0.05 or P<0.01), and unchanged in nonsense ODN groups, respectively. Meanwhile, antisense ODN could significantly antagonize the FSH-promoted cell proliferative activity (P<0.01). Compared with those in the control group, the apoptotic rates and the expression of caspase-3 were dramatically increased in the mid- and high-dose antisense ODN groups (P<0.05 or P<0.01), while the number of cells in G1/G0 phase was significantly decreased and that in S phase distinctly increased (P<0.01). There was no change in nonsense ODN groups (P>0.05). It was suggested that FSH may improve the develop-ment of hOMC cells. However, antisense ODN could inhibit proliferative activity and the FSH-promoted proliferative activity in hOMC cells, at the same time, antisense ODN could inhibit hOMC cell growth by inducing apoptosis.     

Inhibition of microvascular endothelial cell apoptosis by angiopoietin-1 and the involvement of cytochrome C

Background Angiopoietin-1 （Ang-1） is an endothelial-specific growth factor that can promote angiogenesis. Studies demonstrated that Ang-1 can inhibit apoptosis of umbilical endothelial cells, but so far little is known about its effects on apoptosis of microvascular endothelial cells. With the apoptotic model of murine- cerebral-derived microvascular endothelial cells （bEnd.3） induced by serum-free culture,we attempted to clarify the molecular mechanism of bEnd.3 apoptosis, particularly its relation to cytochrome C （Cyt C）. Methods The cultured microvascular endothelial cell strain, bEnd.3 cell, was employed. An apoptotic model of bEnd.3 was established by serum-free culture. Flow cytometry after Annexin labeling and PI staining were used to assess the apoptotic effects of Ang-1 on bEnd.3, and the expression of Bax/Bcl-2, caspase 8, caspase 3, and Cyt C were detected with Western blotting and ELISA. Results The apoptotic rate of bEnd.3 cells after stimulation with Ang-1 （100 ng/L） in serum-free medium was significantly higher than that in control group. Ang-1 inhibited early-stage apoptosis more than late-stage apoptosis provided by propidium iodide （PI） and AnnexinV double staining. The inhibition of Ang-1 on bEnd.3 cell apoptosis was strengthened with the increase in concentration （0-400 ng/ml）. Ang-1 could decrease the expression of Bax, caspase3 and 8, and increase that of Bcl-2. The results of ELISA indicated that Ang-1 significantly decreased CytC content in cytoplasm and increase that in mitochondria. Conclusions Ang-1 could inhibit bEnd.3 apoptosis induced by serum-free medium culture. The apoptosis was associated with decreased Bax expression, increased Bcl-2 expression, which result in Cyt C transferring from mitochondria to cytoplasm, and then caspases activation are reduced and cell apoptosis is suppressed.     

腺病毒介导的白细胞介素10基因转移对胰岛β细胞凋亡及胰岛素释放的影响

Objective To evaluate the efficacy of adenovirus vector-mediated murine interleukin-10 (mIL-10) gene transfer to rat beta cell-RINm5F cells in vitro and to explore the potential value of gene therapy in type 1 diabetes mellitus. Methods The recombinant adenovirus vector Ad-mIL-10 was constructed and transfected into RINm5F cells (Ad-mIL-10 group). Untransfected RINm5F cells and Ad-eGFP-transfected cells were used as controls. The expression of mIL-10 was examined by RT-PCR and Western blot The levels of IL-10 in supernatant were measured by enzyme-linked immunosorbent assay (ELISA). For a determination of insulin release, the cells were cultured with high glucose ( 16. 7mmol/L) for a 1 -hour co-incubation. Then radioimmunoassay was used to detect the level of insulin in supernatant After induction of IL-1β, the levels of nitric oxide (NO) and nitric oxide synthase ( NOS) were measured, the apoptosis of transfected cells was detected by Hoechst 33258 staining and Fas expression by flow cytometry. Results Both mRNA and protein of Ad-mIL-10 were successfully expressed in RINm5F cells. Expression of mIL-10 gene resulted in significant increases in insulin secretion in response to high glucose. Compared with uninfected control and Ad-eGFP infected group, Ad-mIL-10 infected group had decreased levels of NO and NOS induced by IL-lβ [ NO level ( nmol/106 cells): 52. 9 ± 3. 2 vs 227. 3 ± 26. 4, 235. 1 ±28.6, both P＜0.05; NOS level (U/106 cells): 9. 3 ±1.2 vs 29. 8 ±2.5, 30.5 ±2.8, both P ＜ 0. 05]. Furthermore, Ad-mIL-10 gene transfer led to a profound reduction of Fas-expressing islet cells under the induction of IL-1β. Fas-expressing islet cells in Ad-mIL-10 group were significantly lower than those in uninfected group and Ad-eGFP-transfected group (24. 6% ± 1.0% vs 33. 3% ± 5. 1% , 32. 6% ±1.1%) (P＜0.05).The apoptotic rates of Ad-mIL-10 group were lower in comparison with the other two groups (9.4%±1.1% vs 19.2%±2.2%,20.6%±2.3%,P＜0.05).Conclusions IL-10 gene transfer to islet beta cells may be beneficial in maintaining beta cells function,protecting islet cells from IL-1β-mediated apoptosis and promoting islet cells survival.It is a potential therapy for type 1 diabetes mellitus.     

Effect of N-tosyl-L-phenylalanylchloromethyl Ketone on Tumor Necrosis Factor-alpha -induced NF-κB Activation and Apoptosis in U937 Cell Line

Summary: To investigate the effect of N-tosyl-L-phenylalanylchloromethyl ketone (TPCK) on tumor necrosis factor-alpha-induced NF-κB activation and apoptosis in U937 cell line, changes and subcellular localization of NF-κB/p65 and IκB-α were observed by fluorescencemicroscopy and expression and degradation of IκB-α by flow cytometry. The apoptosis of U937 cells was measured by flow cytometry and electrophoresis of DNA. Immunolfluorescence assay showed that NF-κB/p65,IκB-α only localized in cytoplasm. After TNF-α stimulation, p65 was localized only in nuclei, and IκB-α was only localized in cytoplasm and decreased. The changes of TNF-α stimulation were specifically inhibited by TPCK. Flow cytometry also revealed the downregulation of IκB-α protein during TNF-α-induced apoptosis and the down-regulation was specifically inhibited by TPCK. Flow cytometry also showed the apoptosis of U937 cells after TNF-α induction. DNA ladder can be detected in cells treated by TNF-α. It is concluded that degradation of IκB-α protein and NF-κB/p65 translocation occur during TNF-α-induced apoptosis of U937 cells, suggesting the activation of NF-κB.TPCK-sensitive protease plays an important role in the degradation of IκB-α protein induced by TNF-α in U937 cells. TPCK sensitive protease also plays an important role in the apoptosis of U937 cells induced by TNF-α.     

3T3L1脂肪细胞对大鼠胰岛β细胞功能障碍的影响

Objective To investigate the integrated effects of adipocytes on rat beta-cells, differentiated 3T3L1 adipocytes and rat islet cells co-culture system was established. Methods There were two groups; control group ( SD rat islet cells) and co-culture group (islet cells and 3T3L1 adipocytes co-culture system). Islet cells were obtained for determination of (1) insulin secretion and insulin content; (2) mRNA expressions of GLUT2, GCK and Kir6. 2; (3) protein expressions of IR-β, IRS-1 and their tyrosine phosphorylation leveL Results (1) At low glucose, insulin secretion of co-culture group increased compared with that of control group (0.79±0.35) ng·h-1 · ml-1 islet vs (0.38±0.09 ) ng · h-1 · ml-1 · islet, P = 0. 028 . At high glucose, insulin secretion of those two groups was almost at the same level (P =0.760). Compared with control group (2. 84 ±0.92) , stimulation index (SI, insulin release at high glucose/ low glucose) of co-culture system decreased to (1. 57 ±0. 61, P =0.04). And the insulin content of the both groups was almost at the same level (P=0.102). (2) The mRNA of GCK, GLUT2 and Kir6. 2 in co-culture group downregulated to (0. 27 ±0. 11, P = 0. 01) , (0. 34 ±0. 24, P = 0. 009) and (0.41 ± 0. 09, P = 0. 003) compared with control group (mRNA = 1). ( 3) The protein levels of IR-β, IRS-1 and their tyrosine phosphorylation decreased in co-culture system. Conclusions 3T3L1 adipocytes are involved in beta-cell dysfunction, which may facilitate the development of type 2 diabetes. The effects may be mediated by multiple pathways, which include downregulation of GSIS related gene expressions and suppression of islet cell insulin signaling.     

Altered gene expression reveals molecular mechanisms underlying oridonin-induced apoptosis of multiple myeloma LP-1 cells

Objective: To investigate the effect of oridonin on proliferation and invasion of human multiple myeloma LP-1 cells and the underlying mechanism. Methods: LP-1 cells in culture medium in vitro were treated with oridonin at the different concentration. Cell proliferation was measured by Microwave Theory and Techniques (MTT) assay and cell apoptotic rate was detected by flow cytometry. Morphology of cell apoptosis was observed by transmission electron microscope. Expressions of Bax, Bcl-2, Caspase-3, NF-κB as well as I-κB mRNA were detected by real-time PCR. Results: The MTT assays and flow cytometry revealed that oridonin could inhibit the growth of LP-1 cells and cause apoptosis significantly; the suppression was both in time- and dose-dependent manner. Marked morphological changes of cell apoptosis were found under a transmission electron microscope after the cells were treated with oridonin at 25 μmol/L for 24 h. Along with the apoptotic process, Bcl-2, Caspase-3,NF-κB gene expressions were down-regulated (P<0.05). On the contrast, the Bax and I-κB gene expressions were up-regulated (P<0.05). Conclusion: Oridonin could inhibit the proliferation of LP-1 cells via inducing apoptosis. We concluded that oridonin induces apoptosis in LP-1 cells via activation of caspase-3 as well as down-regulation of Bcl-2 and up-regulation of Bax expression. The results suggested that oridonin could induce apoptosis of LP-1 cells through mitochondria- and caspase3-dependent pathways. Meanwhile, the inhibition of NF-κB and the activation of I-κB indicate pro-apoptotic stimuli. In one word, oridonin might be an important potential anti-myeloma reagent.     

Effects of ursolic acid on the proliferation and apoptosis of human ovarian cancer cells

This study examined the effects of ursolic acid （UA） on the proliferation and apoptosis of a human ovarian cancer cell line, CAOV3. The CAOV3 cells were cultured in the RPMI 1640 media and treated with different concentrations of UA （0, 10, 20, 40 μmol/L）. The proliferation rate of the CAOV3 cells was determined by MTT assay. The apoptosis rate was measured by flow cytometry. ERK activity was detected by immunoprecipitation and the expressions of p-ERK1/2, MKP-1, Bax and Bcl-2 by Western blotting. The results showed that the proliferation rate was significantly decreased in the cells treated with UA as compared with that in the non-treated cells （P〈0.05）. The intracellular ERK activity and p-ERK1/2 expression were also reduced in the UA-treated cells, while the MKP-1 expression was elevated. Moreover, the apoptosis was found in the CAOV3 cells exposed to UA; the Bax expression was increased and the Bcl-2 expression decreased. The apoptosis rate in the UA-treated cells was much higher than that in the non-treated cells （P〈0.05）. It is concluded that UA can inhibit the proliferation of CAOV3 cells by suppressing the ERK activity and the expression of p-ERK1/2. And it can also induce the apoptosis of the CAOV3 cells by up-regulating the Bax expression and down-regulating the Bcl-2 expression.     

Effect of Quercetin on Proliferation and Apoptosis of Human Nasopharyngeal Carcinoma HEN1 Cells

The effect of quercetin （Que） on proliferation and apoptosis of human nasopharyngeal carcinoma HEN1 cells was investigated. Inhibition rate of quercetin on HEN1 was assayed by MTT method, apoptosis by flow cytometry （FCM）, and the caspase-3 expression of each group by colorimetry set respectively. Quercetin inhibited HEN1 cells in in a dose-（r=0.709, P〈0.01） and time-dependent manner （r=0.703, P〈0.01）. The ratio of apoptotic and necrosis cells was increased in the cells treated with quercetin. Cell cycle was specificly arrested in G2/M phase. Apoptosis cusp was revealed by FCM. The activity of caspase-3 was significantly up-regulated in 5 groups treated with quecetin as compared with control group （P〈0.05）. It was concluded that the growth inhibition of quercetin was highly related to cell cycle arrest at the G2/M phase and induction of caspase-dependent apoptosis in human nasopharyngeal carcinoma HEN 1 cells.     

Insulin Resistance and Hypertension

The insulin sensitivity in hypertensive patients with normal glucose tolerance (NGT),impaired glucose tolerance (IGT) and type 2 diabetes mellitus (DM) and the insulin resistance (IR) under the disorder or grucose metabolism and hypertension were studied.by glucose tolerance test and insulin release test,insulin sensitivity index (ISI) and the ratio of area under glucose tolerance curve (AUCG) to area under insulin release curve (AUC1) were calculated and analyzed.The results showed that ISI was decreased to varying degrees in the patients with hypertension,the mildest in the group of NGT with hypertension,followed by the group of IGT without hypertension,the group of IGT with hypertension and DM(P=0).There was very significant difference in the ratio of AUCG/AUC1 between the hypertensive patients with NGT and controls (P=0).It was concluded that a significant IR existed during the development of IGT both in hypertension and nonhypertension.The increase of total insulin secretion (AUC1) was associated with nonhypertension simultaneously.IR of the hypertensive patients even existed in NGT and was worsened with the deterioration of glucose metabolism disorder,but the AUC1 in the HT group changed slightly.A relative deficiency of insulin secretion of dysfunction of β-cell of islet existed in IGT and DM of the hypertensive patients.