氧化型低密度脂蛋白诱导分子伴侣GRP78在3T3-L1脂肪细胞中的表达

目的观察氧化型低密度脂蛋白(ox-LDL)诱导3T3-L1脂肪细胞内质网应激相关分子伴侣葡萄糖调节蛋白78(GRP78)的表达,探讨ox-LDL对脂肪细胞内质网应激的诱导作用。方法体外培养3T3-L1脂肪细胞,分别给予不同浓度ox-LDL(50,100,200μg/ml)及内质网应激阳性对照诱导剂衣霉素(Tun)处理。用RT-PCR检测GRP78 mRNA的表达,筛选出最佳干预浓度,用最佳浓度的ox-LDL分别干预脂肪细胞6、12、24 h,分别用RT-PCR、Western印迹法检测GRP78 mRNA、蛋白表达情况。结果 ox-LDL呈浓度依赖方式诱导脂肪细胞GRP78表达,其表达强度随时间延长而增强,24 h达高峰(P<0.05)。结论 ox-LDL可诱导3T3-L1脂肪细胞发生内质网应激,促使未折叠蛋白反应信号通路的分子伴侣表达增加。     

内质网应激在脂肪酸致肝细胞损伤中的作用

目的 通过建立不同的肝细胞脂肪变模型探讨脂肪酸对肝细胞内质网应激的作用,同时检测牛磺熊去氧胆酸(TUDCA)对脂肪变肝细胞内质网应激相关基因表达的影响.方法 以正常成人肝细胞株HL-7702为研究对象,以软脂酸或混合脂肪酸建立肝细胞脂肪变模型,以细胞计数试剂盒细胞增殖法测定和计算细胞活力,观察细胞形态和脂肪变情况,用三酰甘油试剂盒测定细胞内三酰甘油含量.予TUDCA干预,实时PCR方法检测肝细胞内质网应激前后葡萄糖调节蛋白78(GRP78)和CCAAT/增强子结合蛋白同源蛋白(CHOP)的mRNA相对表达量.结果 混合脂肪酸浓度达0.5 mmol/L或软脂酸浓度达0.125 mmol/L即可影响肝细胞活力.单纯软脂酸对肝细胞的损伤作用较混合脂肪酸更强.混合脂肪酸组肝细胞内三酰甘油含量逐渐升高,软脂酸组肝细胞内三酰甘油含量仅于作用12 h时显著增加,其后则无显著改变.混合脂肪酸组不同浓度、不同作用时间下GRP78 mRNA和CHOP mRNA相对表达量与对照组相比差异均无统计学意义(P值均＞0.05).0.5 mmol/L软脂酸作用后肝细胞内CH()P mRNA相对表达量显著升高,但其对GRP78mRNA相对表达量无明显影响.1.0 mmol/L软脂酸作用后肝细胞内GRP78 mRNA和CHOP mRNA相对表达量均显著升高.TUDCA干预低剂量软脂酸组肝细胞内质网应激前后GRP78mRNA和CHOP mRNA相对表达量差异无统计学意义(P值均＞0.05).TUDCA干预高剂量软脂酸组肝细胞内质网应激前后CHOP mRNA表达量差异有统计学意义(12h时为8.6400比5.1032,24 h时为13.7948比6.4928,P值分别=0.042和0.017),但GRP78 mRNA表达量差异无统计学意义(P值均＞0.05).结论 相同的脂肪酸浓度下,软脂酸的比例越高对肝细胞的损伤作用越大.软脂酸呈时间剂量依赖性地调控肝细胞内质网应激.TUDCA可在一定程度上改善软脂酸引起的内质网应激.     

氧化低密度脂蛋白对THP-1细胞凋亡的影响及其机制的研究

目的 探讨氧化低密度脂蛋白(ox-LDL)对培养的人单核巨噬细胞(THP-1)凋亡的影响,并进一步探讨其凋亡产生的机制.方法 体外培养的人THP-1单核细胞经PMA诱导48 h,使形成巨噬细胞,将分化良好的巨噬细胞分别用不同浓度OX-LDL(o～100μg/mL)培养48 h和用75/μg/mL ox-LDL培养THP-1细胞不同时间(0～72 h).应用Annexin-V和碘化丙锭双染色后流式细胞仪检测细胞凋亡,用Western-bolt法检测GRP78、Caspase-12、CHOP蛋白的表达.结果 ox-LDL处理后的细胞凋亡率增加,并且呈时间和剂量依赖性,随着作用时间的延长和浓度的增加,凋亡呈递增变化,同时检测到GRP78、Caspase-12、CHOP蛋白表达都增加.结论 OX-LDL可诱导THP-1细胞凋亡,其凋亡机制有内质网应激途径的参与.     

内脂素经核因子κB途径诱导人单核细胞基质金属蛋白酶-2和9表达的实验研究

目的 探讨内脂素对核因子κB(NF-κB)通路的激活及其在调节人单核细胞基质金属蛋白酶(MMP)-2和MMP-9的表达中的作用,以期进一步了解内脂素与动脉粥样硬化的关系.方法 以健康人外周血单核细胞为研究对象.抽取健康志愿者静脉血,分离、纯化单核细胞后随机分为空白对照组;内脂素组(100、200、400 ng/ml,24 h);Bay11-7082抑制剂组(Bay11-7082 40μmol/ml预孵育30 min,内脂素400 ng/ml刺激24 h).荧光定量PCR检测各组细胞MMP-2和MMP-9 mRNA的表达;Western blot检测MMP-2和MMP-9蛋白的表达;明胶酶谱法检测细胞培养基质中MMP-2和MMP-9的酶活性.内脂素刺激细胞后的核转位分别用Western blot和ELISA进行检测.结果 人外周血单核细胞经不同浓度的内脂素干预培养后24 h单核细胞MMP-2和MMP-9 mRNA及蛋白的表达均明显高于空白对照组(P均<0.05),且呈浓度依赖性.内脂素还上调细胞分泌到细胞培养基中的MMP-2和MMP-9酶活性,内脂素100 ng/ml组MMP-9、MMP-2的酶活性分别为空白对照组的(1.139 ±0.055)和(1.102±0.011)倍(P均<0.05).加入NF-κB抑制剂Bay11-7082后MMP-2、MMP-9的mRNA、蛋白的表达及酶活性均明显低,与内脂素400ng/ml组比较差异均有统计学意义(P均<0.001).内脂素浓度越高,核蛋白NF-κBp65表达越高,内脂素100 ng/ml组相对灰度值为空白对照组的(1.334±0.148)倍(P均<0.05);内脂素浓度越高,NF-κBp65亚单位核内转移越多,内脂素100ng/ml组为0.763±0.056,内脂素400 ng/ml组为1.290±0.065,均大于对照组的0.467±0.046(P均<0.05).结论 内脂素可通过激活NF-κB途径上调人单核细胞中MMP-2和MMP-9表达及活性.这可能是内脂素致动脉粥样硬化及与急性冠状动脉综合征密切相关的机制之一.     

丹参酮ⅡA对血管紧张素Ⅱ诱导的心肌细胞凋亡的抑制作用

目的 在大鼠心肌细胞系H9c2中,观察丹参酮ⅡA对血管紧张素Ⅱ诱导的心肌细胞凋亡和内质网应激及其特异的凋亡分子表达的影响,探讨丹参酮ⅡA抑制血管紧张素Ⅱ(AgⅡ)诱导的心肌细胞凋亡的内质网应激机制.方法 H9c2在CO2孵箱37 ℃常规培养,同步化后进行实验.细胞分为4组.正常对照组.AgⅡ组:10-6 mol/L的AgⅡ孵育48 h.AgⅡ+0.5 μg/mL TSA组同时加入10-6 mol/L的AgⅡ和0.5 μg/mL TSA培养48 h.AgⅡ+1 μg/mL TSA组同时加入10-6 mol/L的AgⅡ和1 μg/mL TSA培养48 h.培养结束,收集细胞进行Hoechst染色检测细胞凋亡的发生,实时荧光定量PCR测定GRP78、CHOP、Caspase-12 mRNA的表达.结果浓度为1 μg/mL TSA可以显著抑制AgⅡ诱导的细胞凋亡(P<0.01).内质网应激通路分子GRP78、CHOP mRNA在给以AgⅡ培养48 h表达较正常培养细胞显著增加,而同时给以0.5 μg/mL TSA可以抑制表达增加(P<0.05),当TSA为1 μg/mL时,抑制作用更明显(P<0.01).结论 TSA可以抑制AgⅡ诱导的心肌细胞系H9c2的凋亡,以及AgⅡ诱导的GRP78,CHOP mRNA表达的增加.     

C反应蛋白对3T3-L1脂肪细胞脂联素表达和分泌的影响

目的 观察C反应蛋白(CRP)对313-L1脂肪细胞脂联素的表达和分泌的影响,并探讨其致胰岛素抵抗的作用机制.方法 分别用Northem印迹、Western印迹等方法观察CRP对脂联素表达及分泌的影响.结果 (1)Northern印迹显示25和50μg/ml CRP作用24 h分别使脂联素mRNA表达下降约31%和52%(均P<0.01),呈剂量依赖趋势;50 μg/ml CRP干预12和24 h分别使脂联素的表达下降约42%和52%(均P<0.01),呈时间依赖趋势.(2)Western印迹显示25和50μg/ml CRP作用24 h分别使脂联素的分泌下降约19%和41%(均P<0.01),呈剂量依赖趋势;50μs/ml CRP干预12和24 h分别使脂联素的分泌下降约29%和41%(均P<0.01).(3)用10 μmol/L磷脂酰肌醇3激酶(PDK)抑制剂LY294002与50μg/ml CRP干预313-L1细胞24 h,可部分逆转CRP对脂联素mRNA表达的抑制作用,使脂联素的表达恢复到对照组的77%.结论 CRP通过PDK途径抑制脂肪细胞脂联索的表达和分泌,可能是其导致胰岛素抵抗机制之一.     

高密度脂蛋白对炎症状态下脂肪细胞胆固醇流出的影响

目的:探讨高密度脂蛋白(High-density lipoprotein,HDL)对体外模拟脂肪细胞炎症状态下胆固醇流出的保护作用及其机制.方法:将前脂肪细胞株3T3-LI(3T3-L1)诱导分化成为成熟的脂肪细胞后,作为空白对照组,脂肪细胞以脂多糖(LPS,100 ng/ml)刺激6小时,为LPS组;脂肪细胞经LPS( 100ng/ml)刺激6小时后,分别用不同浓度HDL孵育16小时,为10 μg/ml HDL+LPS组、50μg/ml HDL+LPS组、100 μg/ml HDL+LPS组.采用液体闪烁计数器检测不同浓度的HDL对LPS刺激的脂肪细胞胆固醇流出的影响,并检测细胞内B族I型清道夫受体(SR-BI)信使核糖核酸(mRNA)和蛋白表达水平.结果:LPS组的胆固醇流出率(2.5±0.6)％较空白对照组(4.1±0.4)％减少,3种不同浓度的HDL+LPS组干预后细胞胆固醇流出率较LPS组增加;LPS组SR-BI mRNA和蛋白表达较空白对照组降低,与LPS组相比较,3种不同浓度的HDL+LPS组SR-BI mRNA和蛋白表达随HDL浓度的增加而递增,差异均有统计学意义(P＜0.05).结论:炎症状态下脂肪细胞的胆固醇流出减少,通过上调SR-BI表达能促进炎性脂肪细胞内胆固醇的流出,减少胆固醇在脂肪细胞内的蓄积.该作用可能与其促进脂肪细胞表达SR-BI有关.     

4,4′-二异硫氰基芪-2,2′-二磺酸对内质网应激诱导心肌细胞损伤的影响

目的探讨氯离子通道阻滞剂4,4′二异硫氰基芪2,2′-二磺酸(DIDS)对衣霉素诱导心肌细胞损伤以及内质网应激标记性分子糖调节蛋白78(GRP78)和CCAAT增强子结合蛋白样同源蛋白(CHOP)的影响。方法取乳鼠心肌细胞培养后,应用衣霉素构建心肌细胞内质网应激模型,随机分为对照组、衣霉素组、衣霉素+DIDS组、DIDS组。应用100ng/ml衣霉素处理24、48、72、96 h;另用DIDS 25、50、75和100μmol/L处理72 h,噻唑蓝法检测心肌细胞存活率,Western blot法检测GRP 78和CHOP蛋白表达水平。结果与对照组比较,衣霉素组48、72和96 h心肌细胞存活率明显降低(P<0.05);与衣霉素组比较,DIDS 50、75和100μmol/L处理明显增加心肌细胞存活率(P<0.05)。与对照组比较,衣霉素组GRP78和CHOP蛋白表达水平明显升高(P<0.05);与衣霉素组比较,衣霉素+DIDS组GRP78和CHOP表达水平明显下调(P<0.05)。结论 DIDS可以抑制衣霉素诱导的大鼠心肌细胞损伤,其机制可能与拮抗GRP78和CHOP的表达,减轻内质网应激有关。     

内质网应激致2型糖尿病缺血心肌易损性增强的机制研究

目的:研究内质网应激(ERS)与脂联素的相关性及其在2型糖尿病缺血心肌易损性增强中的作用。方法:35只C57BL/6J雄性小鼠采用高糖高脂饮食联合链脲佐菌素(STZ)诱导2型糖尿病模型,按随机数字表法将糖尿病小鼠分为对照组(n=5)、牛磺脱氧胆酸(TUDCA)组(n=10)、毒胡萝卜内酯组(n=10)和生理盐水组(n=10)。对照组不做任何处理,其他三组在高糖高脂饲料喂养的最后3周,分别用TUDCA(250 mg/kg)、毒胡萝卜内酯(300μg/kg)和等量生理盐水腹腔注射给药,2次/天,连续给药3周后,TUDCA组、毒胡萝卜内酯组和生理盐水组各随机选取5只建立小鼠在体心肌梗死模型。心肌梗死72 h后,检测心肌梗死面积、血清脂联素含量、心肌组织中脂联素和凋亡相关蛋白C/EBP同源蛋白(CHOP)的含量及脂联素和CHOP mRNA表达水平。结果:TUDCA组及生理盐水组小鼠心肌梗死面积分别为(21.47±2.85)%和(39.92±4.28)%,均小于毒胡萝卜内酯组[(66.56±8.15)%,P均0.01]。心肌梗死前,TUDCA组[(79.25±6.40)pg/ml]和生理盐水组[(70.23±4.15)pg/ml]血清脂联素浓度均高于毒胡萝卜内酯组[(62.64±5.70)pg/ml,P均0.01],各组小鼠心肌梗死前血清脂联素浓度均高于心肌梗死72 h时浓度;各组小鼠心肌组织中脂联素含量及mRNA表达水平检测结果与血清脂联素检测结果一致,而CHOP含量及mRNA表达水平检测结果则与之相反。结论:2型糖尿病导致的心肌缺血损伤加重与ERS相关;ERS可能在2型糖尿病心肌易损性增强中起着重要作用,ERS加重后通过下调脂联素水平,增加了2型糖尿病心肌易损性。     

芹黄素对布雷菲德菌素诱导的神经元样PC12细胞内质网应激途径的影响

目的探讨芹黄素对布雷菲德菌素(BF)A诱导的PC12分化细胞内质网应激(ERS)标志分子葡萄糖调节蛋白(GRP)48及ERS相关促凋亡因子C/EBP环磷酸腺苷反应元件结合转录因子同源蛋白(CHOP)表达水平的影响。方法以神经生长因子(NGF)诱导PC12分化细胞作为模型,流式细胞仪检测不同浓度BFA诱导的PC12分化细胞凋亡情况,MTT法检测芹黄素及BFA作用后细胞存活率,PT-PCR及Western印迹检测芹黄素及BFA作用后GRP78及CHOP mRNA及蛋白表达水平。结果 BFA(0.05、0.10、0.50、1.00、5.00、10.00μmol/L)可诱导PC12分化细胞凋亡,激活ERS凋亡途径。芹黄素(10.00、20.00、40.00μmol/L)预处理可使BFA(1μg/ml)诱导的细胞损伤减轻,使细胞存活率明显提高(P<0.05)。芹黄素(10.00、20.00μmol/L)可抑制BFA(1μg/ml)诱导的GRP78及CHOP表达上调(P<0.05)。结论芹黄素对BFA诱导的ERS损伤有保护作用,抑制GRP78/CHOP信号通路可能是其机制之一。     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Presence of immunoreactive growth hormone and prolactin in the ovine pineal gland

Abstract: The use of antisera raised against bovine growth hormone (GH) and ovine prolactin (PRL) enabled the detection of related immunoreactive (ir) sequences of proteins in ovine pineal tissue. The isolation of PRL-like ir-material was accomplished using a 0.25 M ammonium sulphate (pH 5.5) extraction followed by ethanol precipitation, whereas the resulting 2.0 M ammonium sulphate (pH 7.0) precipitate contained a GH-like immunoreactivity. Gel chromatography of the GH-like immunoreactivity (Sephadex G-100) indicated the presence of several GH-like fragments ranging in the M_r range of 7,000 to 55,000. Analyses of the PRL-like ir-material found in pineal tissue on HPLC using a TSK 545-DEAE column led to the resolution into a single peak of immunoreactivity. A single peak of activity was also observed following chromatofocusing and hydrophobic interaction chromatography of the ir-peak from the TSK 545-DEAE column. The PRL-like ir-material inhibited the binding of [¹²⁵I]ovine PRL-S14 to anti-ovine PRL antibodies without showing an affinity for binding to anti-rat PRL or anti-bovine GH antibodies. Scatchard analysis of the binding of pineal PRL-like ir-material and pituitary ovine PRL-S14 to liver membranes from day-20 pregnant rats revealed similar affinity constants (K_a of 4.7 ± 0.2 × 10⁹ M^-1). In addition, the replication of Nb 2 Node rat lymphoma cells was stimulated by pineal PRL-like ir-material, an effect known to be specific for lactogenic hormones. The pineal PRL-like immunoreactivity appeared on sodium dodecyl sulfate polyacrylamide gels as a single major band of M_r 24,000. The functional status of PRL-and GH-like ir-material in the ovine pineal remains to be determined, but evidence is presented that the overall protein synthesis rate of the rat pineal responded to circulating concentrations of PRL.     

N-acetyl-L-cysteine combined with mesalamine in the treatment of ulcerative colitis： Randomized,placebo-controlled pilot study

AIM： To evaluate the effectiveness and safety of oral N-acetyl-L-cysteine （NAC） co-administration with mesalamine in ulcerative colitis （UC） patients.
METHODS： Thirty seven patients with mild to moderate UC were randomized to receive a four-wk course of oral mesalamine （2.4 g/d） plus N-acetyl-L-cysteine （0.8 g/d） （group A） or mesalamine plus placebo （group B）. Patients were monitored using the Modified Truelove-Witts Severity Index （MTWSI）. The primary endpoint was clinical remission （MTWSI ≤ 2） at 4 wk. Secondary endpoints were clinical response （defined as a reduction from baseline in the MTWSI of ≥ 2 points） and drug safety. The serum TNF-α, interleukin-6, interleukin-8 and MCP-1 were evaluated at baseline and at 4 wk of treatment. RESULTS： Analysis per-protocol criteria showed clinical remission rates of 63% and 50% after 4 wk treatment with mesalamine plus N-acetyl-L-cysteine （group A） and mesalamine plus placebo （group B） respectively （OR = 1.71; 95% CI： 0.46 to 6.36; P = 0.19; NNT = 7.7）. Analysis of variance （ANOVA） of data indicated a significant reduction of MTWSI in group A （P = 0.046） with respect to basal condition without significant changes in the group B （P = 0.735） during treatment. Clinical responses were 66% （group A） vs 44% （group B） after 4 wk of treatment （OR = 2.5; 95% CI： 0.64 to 9.65; P = 0.11; NNT = 4.5）. Clinical improvement in group A correlated with a decrease of IL-8 and MCP-1. Rates of adverse events did not differ significantly between both groups.
CONCLUSION： In group A （oral NAC combined with mesalamine） contrarily to group B （mesalamine alone）, the clinical improvement correlates with a decrease of chemokines such as MCP-1 and IL-8. NAC addition not produced any side effects.     

Delorme's transrectal excision for internal rectal prolapse

Surgical therapy of functional outlet obstruction in patients with internal rectal intussusception may include abdominal, perineal, or transrectal procedures. Because abdominal procedures often result in significant physiologic impact but unrelieved constipation, the authors have elected Delorme's transrectal excision for management of these patients. Since a short-term placebo effect attends many therapies, this report describes results of transrectal excision only after a threeyear postoperative period. Delorme's transrectal excision of internal intussusception accomplished sustained symptomatic relief in over 70 percent of otherwise refractory constipated patients. The association of internal intussusception with other abnormalities underscores the importance of defining both anatomic and functional components when selecting patients whose constipation may require surgical therapy. Critical technical elements, surgical pitfalls, and potential complications of the procedure are discussed.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Toronto, Canada, June 11 to 16, 1989.     

The oral glucose tolerance test: A comparison of the time points on the basis of limit values,normal dispersion,and reproducibility

Summary Time points in the glucose tolerance test (GTT) are compared on the basis of limit values, dispersion within a reference population, and reproducibility. We suggest using the distance between a limit value and the median reference value as a measure of the magnitude of abnormality. The distance between 140 mg/100 ml and the median fasting plasma glucose value is chosen as a standard distance and limits for other points in the GTT are calculated to equal this standard distance of abnormality. We suggest that the probability of correctly interpreting an inividual result is directly related to the reproducibility of the test and inversely related to the percentage of the total range of values which is dispersed among the normal population. The ratio of reproducibility to percentage normal dispersion is proposed as an index of the probability of correctly interpreting an individual result. According to this index, the probability of correct interpretation varies in order: fasting plasma glucose concentration>3-h>2-h>0.5-h>1-h plasma glucose concentration.