高果糖、高脂饲料喂养小鼠肝脏脂质合成酶类与内质网应激相关因子蛋白表达变化

目的 探讨和比较高果糖、高脂饮食诱导的小鼠肝脏三酰甘油(TG)的发生机制及其与内质网应激的关系.方法 成年雄性C57BL/J6小鼠45只,质量25～30 g,按随机数字表随机均分为对照组、高脂组及高果糖组,每组15只.对照组予以普通饲料,高果糖组予以高糖饮食,高脂组予以高脂饮食,3组每日进食热量基本相等,经喂养8周后对小鼠行葡萄糖耐量(ipGTT)实验,处死小鼠后测定各组肝脏三酰甘油含量,并测定肝脏脂质合成酶类和内质网应激相关因子的蛋白表达.结果 不同饲料喂养8周后,高果糖组和高脂组的附睾脂肪含量均为(2.0±0.1)g/100 g(质量),明显高于对照组[(1.2±0.1)g/100 g(质量)P＜0.01].高果糖组和高脂组ipGTT实验后的血糖曲线下面积明显高于对照组(P＜0.01).与对照组相比,高果糖组和高脂组的肝脏TG水平显著增高(P＜0.01),其中高果糖组肝脏TG升高更明显,高果糖组肝脏TG水平显著高于高脂组(P＜0.01).与对照组相比,高果糖组的乙酰辅酶A羧化酶( ACC)、脂肪酸合成酶(FAS)、硬脂酰辅酶A去饱和酶(SCD-1)表达增加(P＜0.01),而高脂组的FAS、ACC、SCD-1的表达减少(P＜0.05);反应内质网应激的磷酸化胰腺内质网激酶(p-PERK)、山梨醇要求激酶-1(p-IRE-1/t-IRE-1)和葡萄糖调节蛋白78(GRP78)蛋白表达在高果糖组和高脂组均增加(P值均＜0.01).结论 高果糖饮食和高脂饮食均可引起脂肪肝,二者通过不同机制引起脂肪肝,高果糖饮食促进内源性脂质生成,高脂喂养抑制肝内源性脂质生成,两种饮食均可诱发内质网应激,提示内质网应激与饮食因子诱导的脂肪肝的发生发展有关.     

长期高果糖饮食喂养对大鼠肝脏脂质沉积和炎症通路的影响

目的 探讨长期(8w)高果糖饮食对大鼠肝脏脂质沉积及肝脏炎症通路的影响.方法 雄性C57BL/J6大鼠分为对照组及高果糖组,经喂养8 w后处死大鼠测定各组肝脏甘油三酯(TG)含量和谷丙转氨酶(ACT)含量,并测定大鼠肝脏内JNK途径(p-JNK/t-JNK)和IκBα途径(p-IKKα/β/t-IKKα/β)的蛋白表达变化.结果 喂养8 w后,与对照组相比,高果糖组肝脏甘油三酯和谷丙转氨酶含量较对照组显著增加(P均＜0.01);与对照组相比,高果糖组的p-JNK/t-JNK、p-IKKα/β/t-IKKα/β和t-IκB的蛋白表达均显著增加(P均＜0.01).结论 8w高果糖喂养引起大鼠肝脏脂质沉积,同时伴有JNK和IKKα/β-NF-κB通路激活,提示肝脏两条炎症通路均介导了高果糖喂养诱导脂肪肝和肝胰岛素抵抗的发生发展.     

高果糖、高脂喂养致小鼠肝脏内质网应激的时程变化

目的探讨高果糖与高脂饮食对比诱导的小鼠肝脏内质网应激(ERS)的发生时程变化。方法雄性C57BL/J6小鼠分为对照组、高果糖组及高脂组,分别在喂养3 d、8 w后测定各组小鼠空腹血糖(FPG)、空腹血清胰岛素(FINS)、肝脏甘油三酯(TG)含量,并测定各组小鼠肝脏ERS标志物——磷酸化胰腺内质网激酶(p-PERK)及磷酸化山梨醇要求激酶-1(p-IRE1/t-IRE1)的蛋白表达。结果喂养3 d后,与对照组相比,两组FPG、FINS无明显变化,而肝TG水平均显著增加;喂养8 w后,与对照组相比,两组FPG、FINS、肝TG水平均显著增加;喂养3 d后,与对照组相比,高果糖组的肝内p-PERK、p-IRE1蛋白表达显著增加,提示出现ERS,而高脂组GRP78、p-PERK的蛋白表达与对照组无显著区别;喂养8 w后,高果糖、高脂组的肝内p-PERK、p-IRE1蛋白表达均显著增加。结论短期和长期高果糖和高脂喂养均可引起肝内脂质沉积,但高果糖喂养小鼠在脂肪肝发生早期即可出现肝ERS,而高脂喂养小鼠则在长期喂养后方出现肝ERS,提示ERS与高果糖、高脂饮食诱导的脂肪肝发生发展均有关,但介导机制不同。     

氧化苦参碱对高果糖饮食诱导大鼠脂肪肝的改善作用及机制研究

观察氧化苦参碱干预对高果糖饮食诱导大鼠胰岛素抵抗和肝脏脂质沉积的影响,并探讨其改善肝脏脂质代谢的分子机制.结果表明高果糖喂养降低大鼠葡萄糖耐量,增加肝脏脂质沉积;而氧化苦参碱可改善大鼠糖耐量和肝脏脂质沉积;高果糖喂养刺激大鼠肝脏脂质合成关键酶蛋白表达,而氧化苦参碱干预显著降低了高果糖喂养诱导的肝脏脂质合成关键酶蛋白表达;高果糖喂养和氧化苦参碱干预对大鼠的线粒体脂肪酸氧化酶类表达无明显影响.     

淫羊藿苷对阿尔茨海默病细胞模型糖原合成酶激酶-3β表达的影响及机制

目的研究淫羊藿苷(ICA)对阿尔茨海默病(AD)细胞模型糖原合成酶激酶-3β(GSK-3β)表达的影响及机制。方法以Aβ25~35孵育PC12细胞制备的AD细胞模型为研究对象,分为对照组、β-淀粉样蛋白(Aβ)组、ICA组、PI3K/Akt信号通路的经典抑制剂(LY)组、ICA+LY组,Western印迹法检测各组的蛋白激酶B(Akt)、p-Akt、GSK-3β、p-GSK-3β的表达。结果与对照组相比,Aβ组的p-Akt水平、p-GSK-3β水平明显下降(P0.01)。与Aβ组相比,ICA组的p-Akt水平、p-GSK-3β水平明显增高(P0.01)。与ICA组相比,ICA+LY组p-Akt水平、p-GSK-3β水平明显下降(P0.01)。结论 ICA可能通过PI3K/Akt信号通路,上调p-Akt、p-GSK-3β蛋白表达,发挥其保护作用。     

内质网应激抑制剂4-苯基丁酸对高果糖喂养诱导小鼠脂肪肝的干预作用及机制

目的探讨内质网应激(ERS)抑制剂4-苯基丁酸(4-PBA)对高果糖饮食诱导小鼠肝脏脂质沉积及脂质从头合成通路的影响。方法雄性Wistar小鼠分为对照组、高果糖组和4-PBA组(自高果糖喂养第4周后给予4-PBA 1 g·kg-1·d-1),8 w后处死小鼠并测定各组小鼠空腹血糖(FBG)、空腹血胰岛素(FINS),测定血清谷丙转氨酶(ALT)、谷草转氨酶(AST)含量及肝脏甘油三酯(TG)含量;测定ERS标志物葡萄糖调节蛋白(GRP)78、GRP94的基因表达;并测定脂质合成标志物固醇调节元件结合蛋白(SREBP)-1c和乙酰辅酶A羧化酶(ACC)的基因表达。结果与对照组相比,高果糖组的FBG、FINS、肝TG均显著增加(均P0.01);与高果糖组比较,4-PBA组的上述指标均显著降低(均P0.01)。与对照组相比,高果糖组小鼠的肝内GRP78、GRP94基因表达显著增加(均P0.01),而4-PBA组上述基因表达均低于高果糖组(均P0.01)。高果糖组小鼠的肝内SREBP-1c和ACC基因表达显著增加(均P0.01),而4-PBA组上述因子基因表达均显著低于高果糖组(P均0.01)。结论长期高果糖喂养引起小鼠肝脏脂质沉积、ERS和脂质从头合成增加,ERS抑制剂4-PBA可改善高果糖饮食诱导的脂肪肝,其机制可能与ERS调控脂质从头合成有关。     

果糖联合高脂饮食对金黄地鼠糖脂代谢的影响

目的通过果糖或葡萄糖联合高脂饮食喂养叙利亚金黄地鼠,比较不同饮食成分喂养对地鼠糖脂代谢的不同影响。方法将金黄地鼠随机分成正常对照组（NC）、高脂组（HF）、果糖高脂组（FRU＋HF）、葡萄糖高脂组（Glu＋HF）,喂养12周,测定体重、血脂、血糖、胰岛素、肝指数,观察肝脏及胰腺形态及组织学变化。结果各高脂喂养组地鼠与对照组比较TC、TG、血糖、LDL-C、HDL-C、肝指数升高,胰岛素水平降低,肝脂肪样变,胰岛增生,其中FRU＋HF组TG、胰岛素敏感性降低,肝指数升高,肝及胰岛病理变化更明显（P〈0．05）。结论果糖高脂喂养的金黄地鼠模型特点为TG显著增高、糖耐量减低、胰岛素抵抗及脂肪肝,更适合作为现代人高果糖高脂饮食导致糖脂代谢紊乱的研究模型。     

罗格列酮对老年胰岛素抵抗大鼠肝脏脂肪酸代谢及胰岛素敏感性的影响

目的 研究罗格列酮对老年胰岛素抵抗(insulin resistance,IR)大鼠肝脏脂肪酸代谢及胰岛素敏感性的影响.方法 22～24月龄雄性Wistar大鼠随机分为老年对照组(OC组)和高脂喂养组.OC组喂饲基础饲料,高脂喂养组喂饲高脂饲料.喂养至第4周末行高胰岛素-正葡萄糖钳夹实验评价高脂喂养组IR状态.判断造模成功后将高脂喂养组随机分为高脂(HF)组和罗格列酮干预(RSG)组.两组除继续喂以高脂饲料外,RSG组予罗格列酮3 mg·kg-1·d-1灌胃,HF组予等体积生理盐水灌胃,继续喂养4 w.实验第8周末,再次行钳夹实验评价各组大鼠胰岛素敏感性;肝脏甘油三酯经氯仿/甲醇抽提后用全自动生化分析仪测定.结果 分组喂养4时,钳夹实验发现高脂喂养组葡萄糖输注率(glucose infusion rates,GIR)低于OC组(P＜0.05),说明高脂喂养组IR模型诱导成功.继续喂养4 w后,HF组GIR进一步下降(P＜0.01),而RSG组GIR与HF组比较明显提高(P＜0.05).与OC组相比,HF组空腹血糖(FBG)、胰岛素(FINS)、游离脂肪酸(FFA)、血清甘油三酯(TG)和总胆固醇(TC)水平升高,而RSG组这些指标较HF组下降(P＜0.01或P＜0.05).肝脏TG含量在HF组高于OC组,RSG组低于HF组;肝脏TG含量与GIR呈负相关,与空腹血糖呈正相关.结论 高脂饮食导致老年大鼠肝脏脂质积聚及IR;罗格列酮干预可改善老年IR大鼠血浆脂代谢异常,降低肝脏脂质含量,提高胰岛素敏感性.     

大黄蒽醌类化合物对HepG2细胞内胰岛素信号通路的激活及其机制

目的 探讨大黄蒽醌类化合物在有或无胰岛素抵抗的情况下是否能激活人肝癌细胞(HepG2)胰岛素信号通路。方法 通过噻唑蓝比色法(MTT法)测定细胞活性,利用醛固酮(ALD)构建HepG2细胞胰岛素抵抗模型,考察2.5～20μmol/L浓度的大黄蒽醌类化合物(大黄酸、大黄酚、大黄素、芦荟大黄素)能否激活HepG2细胞胰岛素信号通路。利用葡萄糖含量检测试剂盒检测细胞葡萄糖,利用糖原含量检测试剂盒检测细胞糖原,通过Western blot检测细胞中磷酸化蛋白激酶B/蛋白激酶B((p-Akt/Akt)、磷酸化糖原合成酶激酶-3β/糖原合成酶激酶-3β(p-GSK-3β/GSK-3β)蛋白表达。采用SPSS 20.0统计软件进行数据分析。根据数据类型,分别采用t检验或方差分析进行组间比较。结果 2.5～20μmol/L浓度的大黄蒽醌类化合物(大黄酸、大黄酚、大黄素、芦荟大黄素)对HepG2细胞的存活率无显著影响(P>0.05)。然而,有或无胰岛素抵抗的情况下均能增加p-Akt/Akt、p-GSK-3β/GSK-3β比值(P<0.05)。进一步研究还发现大黄酸、大黄酚、大黄素处理组的葡萄...     

饮食对胰岛素抵抗大鼠脂肪组织中糖原合成酶激酶3β表达的影响

目的 探讨饮食治疗对胰岛素抵抗大鼠脂肪组织中糖原合成酶激酶3β(GSK-3β)表达的影响.方法 30只SPF级雄性Wistar大鼠随机分为2组,正常对照组(10只,常规饲料喂养)、模型组(20只,高脂饲料喂养;4w后模型形成).模型组随机分为2个亚组(胰岛素抵抗组和饮食干预组,每组10只),胰岛素抵抗组继以高脂饲料喂养,饮食干预组给予普通饲料喂养.6w后,用Western-blot方法检测各组大鼠附睾脂肪组织中GSK-3β的表达,对比各组的表达差异;定期检测大鼠体重、空腹血糖及血浆胰岛素、血甘油三酯和胆固醇,并计算胰岛素敏感指数.结果 高脂饲料喂养4w后,与正常对照组比较,模型组大鼠体重、空腹血糖、胰岛素、胆固醇、甘油三酯显著升高(P＜0.05或P＜0.01),胰岛素敏感指数显著下降(P＜0.01),胰岛素抵抗模型诱导成功;饮食干预6w后与胰岛素抵抗组大鼠比较,脂肪组织中GSK-3β的表达显著下降(P＜0.05);与正常对照组比较,差异无统计学意义.结论 饮食干预能改善大鼠机体胰岛素抵抗,可能与下调脂肪组织GSK-3β的表达有关.     

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.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

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.     

Microbiology of human immunodeficiency virus anorectal disease

PURPOSE: Individuals who are seropositive for the human immunodeficiency virus are at high risk for opportunistic infection and anorectal disorders. Little prospective information is available regarding anorectal pathogens in these patients. METHODS: One hundred sixty-three HIV-seropositive patients presented to the colorectal clinic between 1989 and 1992. Forty-seven (29 percent) patients were thought to have an infectious process and were prospectively studied using a standardized multiculture protocol. RESULTS: Mean age was 33 (range, 19–59) years. All were male; high-risk behavior accounted for 87 percent of HIV transmissions. Presenting complaints included anorectal pain (79 percent), pus per anum (28 percent), and blood per anum (26 percent). Examination revealed perianal tenderness (60 percent), condyloma (38 percent), perianal ulcers (38 percent), and anal fissures (34 percent). Sixty-six sets of cultures were performed; 28 patients had one set, 15 had two sets, and 4 had three sets. Thirty-two of these 47 patients (68 percent) had positive cultures including herpes (50 percent), cytomegalovirus (25 percent),Neisseria gonorrhoeae (16 percent), chlamydia (16 percent), acidfast bacilli (2 percent), and others (9 percent). Six of 32 patients with positive cultures had more than one organism cultured. Sixteen (50 percent) patients with positive cultures were treated medically, 8 (25 percent) were treated surgically and 8 (25 percent) were treated with both modalities. Sixty-one procedures were performed on 17 patients for condylomata. Eighteen patients had 20 procedures for abscesses, 50 percent of whom had positive cultures for other than common bowel flora; all improved. Fourteen patients underwent 33 procedures for perianal fistulas.Mycobacterium fortuitum was cultured from one patient who required 13 procedures for abscesses and fistulas. Forty-five (96 percent) patients were followed for an average of 12.5 months ±2.9 SEM (range, 1–94 months). Symptoms were improved or resolved in 22 of 32 (69 percent) patients with positive cultures and in 11 of 13 (84 percent) with negative cultures. CONCLUSIONS: Specific pathogens may often be identified in human immunodeficiency virus-seropositive patients with anorectal disorders if aggressively sought. Although patients without specific pathogens identified may be expected to improve with planned empiric treatment, positive identification allows more directed therapy.