Influence of ambient temperature on peripherally induced interleukin-1 beta fever in young and old rats

We have previously demonstrated that old and young rats mount similar fevers after intraperitoneal (i.p.) LPS injection at a warm ambient temperature (Ta) of 31 degrees C, but not at a cooler Ta of 21 degrees C. LPS stimulates the synthesis and release of proinflammatory cytokines, particularly interleukin-1 beta (IL-1 beta), necessary for fever development, and possibly this is attenuated at the lower Ta. If so, then administration of exogenous IL-1 beta should enable old rats to mount fevers equivalent to those of young rats regardless of Ta. Here, young (3-5 months) and old (23-29 months) Long-Evans rats were maintained at Ta 21 or 31 degrees C for 3 days prior to i.p. or intravenous (i.v.) injection of rat recombinant IL-1 beta (1 microg/kg) or vehicle. Three days later, rats were given the alternate injection at the same T(a). At least 5 days later, the same rats were injected at the other Ta. Body temperature was continuously monitored throughout the experiments. Young rats mounted fevers after LPS at both Ta's and i.p. fevers were lower than i.v. fevers. Old rats developed fevers that were equivalent to those of young rats at 31 degrees C regardless of route of administration, but no fever responses were evident at 21 degrees C. These data suggest that the attenuated fever of old rats is not due to an inability to produce IL-1 beta, but rather to a deficiency further along in the fever pathway. In addition, these results show that, as with LPS, Ta plays a role in the ability of old rats to mount fever in response to IL-1 beta.     

Hypothalamic 11,12-epoxyeicosatrienoic acid attenuates fever induced by central interleukin-1beta in the rat

Inhibitors of cytochrome P-450 augment fever in rats and mice, indicating that the metabolite of the enzyme is candidate of endogenous antipyretic. Cytochrome P-450 of arachidonic acid cascade leads to the formation of regioisomeric 5,6-, 8,9- 11,12- and 14,15-epoxyeicosatrienoic acid (EET). Various isomers of EET were administrated into the preoptic area and anterior hypothalamus (PO/AH) to test their influence on fever induced by interleukin-1β (IL-1β) administrated into the PO/AH in conscious rats. The IL-β-induced fever was attenuated in the 11,12-EET-pretreated rats, although 5,6-, 8,9- and 14,15-EET did not affect the fever. Intra-PO/AH injection of 11,12-EET did not alter normal body temperature. The results suggest that 11,12-EET acts in the hypothalamus as an endogenous antipyretic.     

内毒素诱发肝硬化大鼠发生肝性脑病的实验研究

目的：观察外源性内毒素诱发肝硬化大鼠发生肝性脑病的可能性及可能机制。方法：采用腹腔内小剂量内毒素一次性注射（３００μｇ／１００ｇＢＷ）诱发肝硬化大鼠发生肝性脑病。结果：小剂量内毒素腹腔内注射可以诱发肝硬化大鼠发生肝性脑病。内毒素注射后,动物一般行为状态及脑电图皆有明显变化,与其他肝性脑病模型或肝性脑病病人类似。同时,血氨和胰高血糖素水平显著升高。血浆内毒素含量与血氨、血胰高血糖素含量之间及血氨与务     

白介素18在脂多糖致大鼠脑水肿中的表达

目的探讨白介素18（IL-18）在脂多糖（LPS）致大鼠脑水肿发病过程中的表达及纳络酮对其干预作用。方法SD大鼠84只，对照组（NS组）：28只，0．2mL生理盐水颈内动脉注射；内毒素组（LPS组）：28只，颈内动脉注射LPS 200μg；纳络酮治疗组（NAL组），28只，颈内动脉注射LPS后10min、1、2、6、12h及处死前2h腹腔注射纳络酮1mg／kg。于不同时间点测定脑组织匀浆IL-18的含量。干湿法测定脑组织含水量，甲酰胺法测定伊文思兰（EB）含量。结果LPS组脑组织含水量和EB含量显著高于NS组（P〈0．01）。NAL组脑组织含水量和EB含量显著低于LPS组（P〈0．01），但仍较NS组高（P〈0．01）。LPS组IL-18的含量显著高于NS组（P〈0．01）。NAL组IL-18在4、6、12h时表达降低，与LPS组比较差异显著（P〈0．05或P〈0．01），但在48h时差异无显著性（P〉0．05）。LPS组脑组织含水量和EB含量呈正相关（r=0．743，P〈0．01），IL-18含量与含水量呈正相关（r=0．616，P〈0．01），IL-18含量与EB含量呈正相关（r=0．497，P〈0．01）。结论IL-18参与了脑水肿的发生发展，纳络酮可以抑制IL-18的生成，减轻脑水肿。     

The Myc-dependent angiogenic switch in tumors is mediated by interleukin 1beta

Although induction of blood vessel growth is acknowledged as a pivotal requirement for the evolution of macroscopic tumors, the events that trigger onset of tumor angiogenesis remain largely obscure. The pervasive Myc oncoprotein is itself a potent inducer of angiogenesis in a wide range of tissues. We have used a reversibly switchable mouse transgenic model of Myc-dependent beta-cell carcinogenesis to delineate the kinetics and causal sequence of angiogenic processes following acute Myc activation. We show that onset of endothelial cell proliferation is induced shortly after Myc-induced cell cycle entry of beta cells. Endothelial cell proliferation is not indirectly induced by local tissue hypoxia but instead via a diffusible angiogenic signal produced by Myc-expressing beta cells. This signal triggers the release of pre-existing, sequestered VEGF from the islet extracellular matrix, that then homes to the endothelial compartment where it induces endothelial cell proliferation. Myc activation in beta cells rapidly induces expression and release of the proinflammatory cytokine interleukin 1beta (IL-1beta). We show that IL-1beta is the principal effector downstream of Myc responsible for triggering rapid onset of islet angiogenesis. Together, our data delineate a complete pathway in vivo by which the highly pleiotropic Myc oncoproteins elicits coexpansion of the vascular compartment during tumorigenic progression.     

The pharmacokinetics, distribution and degradation of human recombinant interleukin 1 beta in normal rats

Based upon in vivo rat experiments it was recently suggested that interleukin 1 in the circulation may be implicated in the initial events of beta-cell destruction leading to insulin-dependent diabetes mellitus (IDDM) in humans. The aim of the present study was to estimate half-lives of distribution (T1/2 alpha) and elimination phases (T1/2 beta) of human recombinant interleukin 1 beta (rIL-1 beta), and its tissue distribution and cellular localization by means of mono-labelled, biologically active 125I-rIL-1 beta. After intravenous (i.v.) injection, 125I-rIL-1 beta was eliminated from the circulation with a T1/2 alpha of 2.9 min and a T1/2 beta of 41.1 min. The central and peripheral volume of distribution was 20.7 and 19.1 ml/rat, respectively, and the metabolic clearance rate was 16.9 ml/min/kg. The kidney and liver showed the highest accumulation of tracer, and autoradiography demonstrated that 125I-rIL-1 beta was localized to the proximal tubules in the kidney and to the hepatocytes in the liver. Furthermore, grains were localized to the islets of Langerhans in the pancreas. Tracer-bound proteins corresponding to intact 125I-rIL-1 beta were found in the circulation after i.v., intraperitoneal (i.p.) and subcutaneous (s.c.) injections, as demonstrated by high performance size exclusion chromatography, trichloracetic acid precipitation and SDS-PAGE until 5 h after tracer injection. Pre-treatment with 'cold' rIL-1 beta enhanced degradation of a subsequent injection of tracer. The route of administration was of importance for the biological effects of rIL-1 beta, as demonstrated by a reduced food intake, increased rectal temperature and blood glucose after s.c. injection of rIL-1 beta compared with i.p. The present demonstration of intact rIL-1 beta in the circulation and the islets of Langerhans supports the hypothesis that systemic IL-1 beta may be involved in the initial beta-cell destruction leading to IDDM in humans.     

血红素加氧酶-1在铁代谢中的作用

铁是机体必需的微量元素,有着广泛的生物学作用,包括氧化运输和细胞呼吸作用,缺铁会引起细胞生长停滞或死亡,铁过载会使细胞发生氧化应激进而损伤细胞膜、蛋白质、核酸.血红素加氧酶-1(HO-1)分解血红素产生铁是铁重复利用最主要的来源,在铁代谢中的作用至关重要.     

Induction of articular cartilage degradation by recombinant interleukin 1 alpha and 1 beta

The purpose of this study was to compare the effects of human recombinant interleukin 1, alpha and beta, on articular cartilage. The effects of rIL-1 alpha and rIL-1 beta on proteoglycan degradation and synthesis following treatment of bovine articular cartilage in serum-free organ culture were quantified. Purified human IL-1 and both rIL-1 alpha and rIL-1 beta induced a two-fold or greater increase in glycosaminoglycan (GAG) release from cultured articular cartilage. Levels or rIL-1 alpha as low as 15 pM induced increased proteoglycan degradation whereas identical levels of rIL-1 beta did not. Killing of the cartilage cells abolished induced GAG release by all forms of IL-1. Analysis of proteoglycan size following IL-1 treatment showed limited degradation of material released into the culture medium or remaining within cartilage. Both forms of recombinant IL-1 inhibited GAG synthesis when continually present in the culture medium. Actinomycin D and cycloheximide inhibited IL-1 dependent cartilage destruction whereas indomethacin did not.     

氨基葡萄糖对白细胞介素1β诱导体外培养人骨关节炎软骨细胞蛋白聚糖代谢的影响

背景：蛋白聚糖和胶原纤维的降解是骨关节炎发病的主要生理和病理学基础,氨基葡萄糖不仅可以减轻骨关节炎疼痛症状,同时可以延缓骨关节炎的病理改变。 目的：了解氨基葡萄糖对白细胞介素1β诱导骨关节炎软骨细胞蛋白聚糖代谢的影响。 方法：取骨关节炎患者的软骨细胞,分阶段酶消化法进行体外原代培养。在培养液中加入白细胞介素1β诱导剂,设立不含药兔血清对照组、白细胞介素1β对照组和加入不同浓度兔氨基葡萄糖含药血清的实验组。 结果与结论：各浓度氨基葡萄糖含药血清组体外培养软骨细胞释放入培养液中糖胺聚糖百分比均值明显低于对照组(P < 0.01),随氨基葡萄糖浓度的增加,糖胺聚糖百分比逐渐降低;蛋白聚糖合成标记物3B3含量的均值较对照组明显增高(P < 0.01),与氨基葡萄糖浓度呈正相关;而蛋白聚糖降解标记物5D4含量的均值则正相反;氨基葡萄糖可以增加骨关节炎患者软骨细胞蛋白聚糖mRNA表达,减低基质金属蛋白酶1,3 mRNA表达。表明氨基葡萄糖可以抑制白细胞介素1β对骨关节炎患者软骨细胞蛋白聚糖代谢的促进作用,达到保护软骨,防止骨关节炎的目的。     

Role of interleukin-1beta in the modulations of cytochrome P450 and heme metabolism in rat liver.

The effect of recombinant human interleukin-1beta (IL-1beta) on the modulation of hepatic cytochrome P450 (P450) was investigated by in vivo subcutaneous dosing studies in male Sprague-Dawley rats. To assess the effect of IL-1beta on heme metabolism, we determined the delta-aminolevulinic acid synthetase (delta-ALAS) and heme oxygenase activities in the liver. IL-1beta suppressed the microsomal total P450 and heme contents and delta-ALAS activity in the liver. In contrast, microsomal heme oxygenase activity was significantly increased by the IL-1beta treatments. Western blot analysis and marker enzyme activities for individual P450 isoforms demonstrated that IL-1beta suppressed CYP2C6, 2C13, 2E1, and 3A2, whereas CYP2A, 2B1/2, 2C11, and 4A1 were not influenced by the treatments. IL-1beta inhibited both allylisopropylamide- and phenobarbital-inducible delta-ALAS activities in the liver. These results indicate that IL-1beta has differential effects on the constitutive P450, and also on delta-ALAS and heme oxygenase activities in rat liver. Thus, the modulation of hepatic P450 by IL-1beta is complex, and IL-1beta may be involved in the regulation of both apoprotein synthesis for each P450 isoform and the heme pools in the liver.     

In vitro production of human interleukin 1 alpha and interleukin 1 beta by peripheral blood mononuclear cells examined by sensitive sandwich enzyme immunoassay

The in vitro production of human interleukin 1 alpha (hIL 1 alpha) and interleukin 1 beta (hIL 1 beta) by peripheral blood mononuclear cells was examined by sensitive sandwich enzyme immunoassays which could discriminate hIL 1 alpha and hIL 1 beta without cross-reaction with human IL2. In culture supernatants of mononuclear cells, two components were detected by sandwich enzyme immunoassay for hIL 1 alpha or hIL 1 beta. The molecular weight of one component was shown to be equal to that of recombinant hIL 1 alpha or hIL 1 beta by gel filtration. The elution volume of the other component corresponded to a molecular weight of about 30,000. The sum of the two components for both hIL 1 alpha and hIL 1 beta in culture supernatants of peripheral blood mononuclear cells from healthy subjects increased 1.7 to 38-fold by Escherichia coli lipopolysaccharide. The sum of the two components for hIL 1 beta was 13 to 97-fold larger than that for hIL 1 alpha.     

Role of interleukin 1 beta in esophageal squamous cell carcinoma

Interleukin (IL)-1 beta has been reported to be a marker of shorter survival in gastric and colorectal adenocarcinoma. In the present study, we examined the potential role and prognostic value of IL-1 beta in esophageal squamous cell carcinoma (SCC). Human esophageal SCC cell line, CE81T, was selected for cellular and animal experiments, in which biological changes after experimental manipulation of IL-1 beta signaling were explored, including tumor growth, invasion capacity, and the sensitivity to treatment. Moreover, 147 esophageal SCC samples were analyzed using immunohistochemical staining to correlate the expression of IL-1 beta with clinical outcome. Our data revealed that IL-1 beta was significantly overexpressed both at mRNA and protein levels in cancer specimens compared to nonmalignant tissues. When IL-1 beta signaling was blocked, tumor growth, invasion ability, and treatment resistance were attenuated. Activation of NF-kappa B, increase of E2-EPF ubiquitin carrier protein and subsequent epithelial–mesenchymal transition might be the underlying mechanisms of the more aggressive tumor growth in IL-1 beta-positive esophageal cancer. The immunochemistry findings indicate that positivity staining of IL-1 beta correlated significantly with higher clinical stage, lower response rate to concurrent chemoradiotherapy (CCRT), and higher recurrence rate after curative treatment. Moreover, IL-1 beta was a significant predictor of survival in patients undergoing surgical intervention or definite CCRT. In conclusion, IL-1 beta is significantly linked to poor prognosis for patients with esophageal cancer and may be a promising molecular target for therapeutic intervention for esophageal SCC.     

Effect of ibuprofen on fever and metabolic changes induced by continuous infusion of leukocytic pyrogen (interleukin 1) or endotoxin

Many of the metabolic sequelae to infection and inflammation, such as fever, trace mineral redistribution, skeletal muscle catabolism, and the acute-phase protein response, are mediated by leukocytic pyrogen (interleukin 1). In the anterior hypothalamus and in skeletal muscles leukocytic pyrogen appears to induce the synthesis of prostaglandin E2 which mediates fever and skeletal protein catabolism. It is unclear whether any additional metabolic responses to leukocytic pyrogen result from prostaglandin production. This study was undertaken to investigate the ability of ibuprofen, a specific cyclooxygenase inhibitor, to alter protein and trace metal responses to leukocytic pyrogen or endotoxin when given in quantities sufficient to block the febrile response. In guinea pigs given continuous infusions of leukocytic pyrogen or endotoxin, a 0.6 to 0.8 degrees C fever was observed within 4 h, and zinc and iron concentrations in serum fell by 63 to 78% (P less than 0.01). Rates of whole body amino acid appearance, oxidation, and incorporation into protein were all significantly increased by leukocytic pyrogen and endotoxin treatment, (P less than 0.05) as were the fractional hepatic and seromucoid protein synthesis rates in leukocytic pyrogen-treated animals (P less than 0.01). Muscle protein synthesis was unchanged. Although pretreatment with infusions of ibuprofen completely ablated the febrile response to leukocytic pyrogen and endotoxin, decreases in zinc and iron concentrations in serum and leukocytosis were unaffected. Overall increases in whole body amino acid kinetics induced by leukocytic pyrogen or endotoxin were only minimally affected by ibuprofen. We concluded that treatment with prostaglandin synthesis inhibitor ibuprofen did not affect whole body trace metal, hematological, or hepatic acute-phase-induced responses to leukocytic pyrogen or endotoxin, either because these responses are prostanoid independent or because they are only partially mediated by eicosanoid products.     

Drug metabolism in rats with arthritis induced by 6-sulfanilamidoindazole (6-SAI)

Hexobarbital sleeping time was prolonged and ethylmorphine N-demethylation was inhibited after a single dosage or seven administrations of 6-SAI to old rats. These effects were independent of the development of arthritis. Changes in cytochrome P-450 concentration after 6-SAI treatment were insignificant and thus not responsible for the decrease in drug metabolism.In vitro 6-SAI inhibited ethylmorphine N-demethylation; the inhibition was of a mixed type. 6-SAI bound to cytochrome P-450 and induced a type II spectrum. The magnitude of hexobarbital-induced type I spectral changes was diminished by 6-SAI.It is concluded that 6-SAI inhibits cytochrome P-450-dependent drug metabolism by binding to cytochrome P-450.     

Prostaglandin E1 fever induced in rabbits

1. Micro-injections of prostaglandin E(1) (PGE(1)) into the anterior hypothalamus of the rabbit produced fever which was nearly immediate in onset. The prostaglandin sensitive region appears to be identical to that described as being fever sensitive to leucocytic pyrogen.2. Micro-injections of PGE(1) into the posterior hypothalamus and midbrain reticular formation of the rabbit did not produce fever.3. The febrile response to PGE(1) injected into the anterior hypothalamus was dose dependent over a range of 20-1000 ng.4. Ambient temperature influenced the thermoregulatory mechanism by which PGE(1) fever evolved. In the cold, PGE(1) fever was due to increased heat production while during heat exposure both evaporative and dry heat losses were reduced without significant changes in heat production. Vasoconstriction, confined mainly to the ears, was effective in producing fever in standard room environments (24-25 degrees C) along with a small increase in heat production.5. The preoptic anterior hypothalamic area retained its thermosensitivity during PGE(1) fever; heating this area attenuated, while cooling augmented the fever.6. The results support the view that PGE(1) is a mediator of pyrogen induced fever.     

Cloning, sequence and expression of bovine interleukin 1 alpha and interleukin 1 beta complementary DNAs

Interleukin 1 (IL-1) is a cytokine which mediates a variety of immunoregulatory and inflammatory activities. Using human IL-1 alpha and IL-1 beta probes, cDNAs for the corresponding bovine genes were isolated from an alveolar macrophage library. The open reading frames of the bovine IL-1 alpha and IL-1 beta cDNAs encode proteins of 268 and 266 amino acids, respectively, each with a predicted mol. wt of approx. 31,000. Both forms of bovine IL-1 exhibit a high degree of sequence homology with IL-1 gene products from other mammalian species. Based upon comparisons with human IL-1 amino acid sequences, the post-translationally processed, mature forms of bovine IL-1 would occur as 17-18,000 mol. wt proteins. Sequences encoding mature bovine IL-1 alpha and IL-1 beta were inserted into E. coli expression plasmids and biologically active proteins were synthesized as judged by the ability of the recombinant proteins to induce proliferation of bovine thymocytes. Both IL-1 alpha and IL-1 beta exist as single genomic copies. In addition, bovine IL-1 beta mRNA is approx. 10-fold more abundant than IL-1 alpha mRNA in stimulated alveolar macrophages.     

Hepatic and skeletal muscle phospholipid metabolism in recovering burned rats

Liver and soleus muscles of control animals and rats recovering from a single hindlimb scald were analyzed for diphosphatidyl glycerol, phosphatidyl ethanolamine, phosphatidyl choline, sphingomyelin, lysophosphatidyl choline, phosphatidyl inositol, and phosphatidyl serine. Liver of 4-hr postburn rats exhibited decreased contents of diphosphatidyl glycerol (-20%), phosphatidyl ethanolamine (-11%), and phosphatidyl choline (-7%). At 3 days after the burn, only an 11% decrease in hepatic phosphatidyl inositol was observed. Soleus muscle of the unburned limb of burned rats showed at 3 days postburn an 11% decrease in sphingomyelin content but the other measured phospholipids were at control level. In contrast, soleus muscle from the contralateral burned limb exhibited increased contents of sphingomyelin (+29%), lysophosphatidyl choline (+145%), and phosphatidyl serine (+27%) compared to control uninjured animals. It also showed a 25% higher phosphatidyl inositol level than the contralateral uninjured counterpart. It is concluded that recovery from a single hindlimb scald is associated with alterations in phospholipid metabolism in the liver and in the region of the wound. The local response to thermal injury may be mediated, in part, by stimulated activity of phospholipase A2.     

Hepatic metabolism of ibuprofen in rats under acute hypobaric hypoxia

Hypobaric hypoxia induced at high altitude causes a subnormal oxygen concentration in cells which affects the drug metabolic and pharmacokinetic (PK) capacity of the body. The metabolism and PK of drugs like ibuprofen may be impaired under hypoxia and may require a different than usual therapeutic dose regimen to ensure safe therapy. The present investigation was undertaken to evaluate the effect of acute hypobaric hypoxia (AHH) on hepatic metabolism and PK of ibuprofen in rats. Animals were exposed to simulated altitude of 7620 m (～25,000 ft) for AHH exposure (6 and 24 h) in a decompression chamber and were administrated with single dose of ibuprofen (80 mg/kg body weight, p.o.). The results showed that GST activity was significantly reduced at 6 h (15%) and 24 h (23%) (p < 0.05) in hypoxic group as compared to normoxic. A significant increase by 20–24% (p < 0.05) in AST level was observed after AHH exposure. LDH activity also exhibited significant increase (p < 0.05) after 24 h of AHH. A significant down-regulated CYP2C9 level and mild histopathological changes were observed after 24 h of AHH. Furthermore, PK variables viz. elimination half-life (T½) and mean residence time (MRT) of ibuprofen exhibited significant increase by 42% and 51% (p < 0.05) respectively after 24 h of AHH. Thus, results suggest that AHH exposure of 24 h significantly affects phase II conjugation pathway, CYP2C9 level, AST level, liver histology and PK parameters. This asserts that AHH can impair disposition of ibuprofen however, it requires further investigation under chronic hypobaric hypoxic conditions.