急性肺损伤幼鼠肺泡Ⅱ型上皮细胞和SP-A变化相关性的研究

目的：该实验旨在研究急性肺损伤（ALI）时肺泡Ⅱ型上皮细胞（AEC-Ⅱ）超微结构变化和肺组织表面活性蛋白SP-A含量的变化关系，从而探讨ALI的发病机制。方法：48只Sprague-Dawley幼鼠被随机分为正常对照组和ALI组。 腹腔注射脂多糖（LPS，4 mg/kg）建立ALI模型，正常对照组注射等量生理盐水。 LPS注射后24，48，72 h每亚组各处死8只大鼠。 取左肺下肺组织待透射电镜检查。 用Western blot方法测定肺组织SP-A的相对含量。结果：ALI 24 h时，AEC-Ⅱ微绒毛消失。24 h及48 h时板层小体（lamellar body, Lb）数量增加，体积增大，密度减低，排空明显增强，呈指环状绕核排列，细胞增生活跃，代谢旺盛。48 h时Lb呈巨大空泡样变性。肺组织SP-A含量明显高于对照组（24 h时ALI组为6.52±0.62，对照组为5.02±0.35， P< 0.01；48 h时ALI组为6.65±0.62，对照组为5.01±0.36，P< 0.01）。72 h时Lb破溃，数目明显减少，细胞核形态不规则，部分核边界不清，肺组织SP-A含量下降(ALI组为3.87±0.50，对照组为5.22±0.36，P<0.01)。结论： LPS致幼鼠ALI时AEC-Ⅱ和肺组织SP-A的变化为时间依赖性，随AEC-Ⅱ损伤程度的加重肺组织SP-A由代偿转为失代偿，可能是发生ARDS的重要机制之一。     

脂多糖对大鼠实验性变应性鼻炎的影响

目的研究脂多糖(Lipopolysaccharide,LPS)对实验性变应性鼻炎的影响。方法SD大鼠40只随机分4组,其中,变应性鼻炎组经腹腔注射及鼻腔滴入卵清白蛋白(OVA)致敏,建立变应性鼻炎动物模型;LPS刺激组经鼻腔滴入LPS(10μg/100μL);变应性鼻炎 LPS刺激组为大鼠激发成变应性鼻炎后再以LPS滴入鼻腔。观察各组的症状变化,如喷嚏,流涕等。行常规HE及甲苯胺蓝染色观察各组鼻黏膜炎性细胞的浸润情况,并行高倍镜下嗜酸性粒细胞计数。结果①变应性鼻炎 LPS刺激组过敏症状评分高于其余各组(P<0.01);正常对照组及LPS刺激组症状评分差异无显著性(P>0.05)。②变应性鼻炎 LPS刺激组鼻黏膜中嗜酸性粒细胞计数高于变应性鼻炎组,差异有显著性(P<0.05);正常对照组及LPS刺激组鼻黏膜中嗜酸性粒细胞计数差异无显著性(P>0.05)。结论LPS刺激可以加重变应性鼻炎的症状及鼻黏膜组织的病理学改变。     

Mechanism of decrease in levels of hepatic P450 isozymes induced by intracerebral endotoxin: independence from sympathetic nervous and adrenocortical systems

We previously reported that lipopolysaccharide (LPS) injected intracerebroventricularly (i.c.v.) at an ineffective dose (0.1 μg/rat) decreased the drug metabolizing activities and related cytochrome P450 (CYP) isozymes in rat liver microsomes when injected intraperitoneally (i.p.). The dose study (doses <0.1 μg intracerebrally and >0.1 μg i.p.), which was carried out to examine how much more effective is i.c.v.-LPS than i.p.-LPS, showed that the pattern of alteration of expression of CYP isozymes induced by i.c.v.-LPS was different from that caused by i.p.-LPS at an effective dose (10 μg/rat). These results indicate that the decrease in hepatic CYP isozymes caused by i.c.v.-LPS could not be explained by the LPS leaked from the brain, suggesting that the decrease in hepatic CYP isozymes by i.c.v.-LPS may be caused by a central action of LPS. In this study, the possible involvement of sympathetic nervous and adrenocortical systems in the down-regulation of CYP isozymes by i.c.v.-LPS was investigated using surgical or chemical sympathetecomized or adrenalectomized rats. The norepinephrine (NE) content in the liver in rats with surgical hepatic sympathetectomy was reduced by 88% compared with that of sham-operated rats that received i.c.v.-saline and 85% compared with that of sham-operated rats that received i.c.v.-LPS, indicating that hepatic denervation was successful. The NE content in the liver in rats chemically sympathetectomized by two i.p. injections of 6-hydroxydopamine (40 mg/kg each time) 1 and 2 days before i.c.v. injection was reduced by 82% in i.c.v.-saline-treated and by 74% in i.c.v.-LPS-treated groups compared with that in rats pretreated with i.p.-saline. These results indicate that sympathetic NE terminals were effectively removed. Intracerebroventricular LPS decreased the total P450 content and the activities of CYP dependent drug metabolizing enzymes, ethoxyresorufin O-deethylase (EROD), pentoxyresorufin O-depentylase (PROD), imipramine N-demethylase (IMND) and erythromycin N-demethylase (ERND) after 24 h in both sympathetectomized rats and non-denervated rats. Adrenalectomy (ADX) reduced the level of corticosterone in serum by 81% compared to sham-operated rats, indicating that adrenalectomy was successful. ADX did not inhibit the decrease in the total P450 content and the metabolism of drugs induced by i.c.v.-LPS, but more profoundly emphasized the inhibitory effect of i.c.v.-LPS than the sham-operation. These results suggest that the sympathetic nervous systems both directly and indirectly innervating the liver do not participate in the primary mechanism of the decrease in the activities of CYP isozymes in rat liver microsomes induced by i.c.v.-LPS. Also, the adrenal glands, especially the adrenocortical system, play a suppressive role in the decrease in CYP isozymes caused by i.c.v.-LPS. Received: 31 August 1998 / Accepted: 24 November 1998     

骨碎补总黄酮对急性肾衰竭大鼠ICAM-1基因表达的影响

目的：研究骨碎补总黄酮（AFFDR）对大肠杆菌脂多糖（LPS）诱导的急性肾衰竭大鼠肾组织细胞间黏附因子-1（ICAM-1）mRNA表达的影响。方法：用LPS（30mg/kg）腹腔注射建立急性肾衰竭大鼠模型,分模型组（LPS组）、骨碎补总黄酮治疗组（LPS＋AFFDR组）、正常对照组（Control组）和骨碎补对照组（AFFDR组）。实验第7天测定各组大鼠血清肌酐（Scr）的含量,观察肾脏的超微结构和ED-1阳性巨噬细胞的浸润,并用半定量RT-PCR方法检测AFFDR对肾组织ICAM-1 mRNA表达的影响。结果：LPS引起大鼠Scr明显升高,肾脏近曲小管出现明显病理改变。AFFDR有效降低LPS攻击大鼠Scr的含量,明显减轻近曲小管的损伤。LPS组肾组织ED-1阳性巨噬细胞浸润和ICAM-1 mRNA的表达明显高于对照组,而LPS＋AFFDR组肾组织ED-1阳性巨噬细胞的浸润和ICAM-1 mRNA的表达明显低于LPS组。结论：AFFDR防治内毒性急性肾衰竭的作用机制可能与其抑制肾组织ED-1阳性巨噬细胞浸润和ICAM-1的表达有关。     

Rough mutants defective in core and O-polysaccharide synthesis and export induce antibodies reacting in an indirect ELISA with smooth lipopolysaccharide and are less effective than Rev 1 vaccine against Brucella melitensis infection of sheep

Classical brucellosis vaccines induce antibodies to the O-polysaccharide section of the lipopolysaccharide that interfere in serodiagnosis. Brucella rough (R) mutants lack the O-polysaccharide but their usefulness as vaccines is controversial. Here, Brucella melitensis R mutants in all main lipopolysaccharide biosynthetic pathways were evaluated in sheep in comparison with the reference B. melitensis Rev 1 vaccine. In a first experiment, these mutants were tested for ability to induce anti-O-polysaccharide antibodies, persistence and spread through target organs, and innocuousness. Using the data obtained and those of genetic studies, three candidates were selected and tested for efficacy as vaccines against a challenge infecting 100% of unvaccinated ewes. Protection by R vaccines was 54% or less whereas Rev 1 afforded 100% protection. One-third of R mutant vaccinated ewes became positive in an enzyme-linked immunosorbent assay with smooth lipopolysaccharide due to the core epitopes remaining in the mutated lipopolysaccharide. We conclude that R vaccines interfere in lipopolysaccharide immunosorbent assays and are less effective than Rev 1 against B. melitensis infection of sheep.     

The role of interleukin-1β in febrile seizures

Febrile seizures (FS) occur in children as a result of fever. Despite their prevalence, the pathophysiology of FS has remained unclear. Recent evidence from clinical and experimental studies has highlighted a potential role of immune generated products in the genesis of FS. Of particular interest are the pro-inflammatory cytokine, interleukin-1beta (IL-1β) and its naturally occurring antagonist, interleukin 1 receptor antagonist (IL-1ra). Using a novel animal model of FS, involving the generation of physiological fever, we investigated the role of the IL-1β/IL-1ra system in the genesis of FS. We found that animals with FS had increased hippocampal and hypothalamic IL-1β compared to equally treated animals without FS, which was first evident at onset of FS in the hippocampus. There were no differences in IL-1ra levels. ICV IL-1β increased the number of animals with FS while IL-1ra had an opposite anti-convulsant effect. The data from these studies, in combination with recent results from other laboratories, have established a putative role for the IL-1β/IL-1ra system in the genesis of FS.     

CD14的表达及其在库普弗细胞激活中的意义

目的　探讨LPS对库普弗细胞 (KC)CD14表达的影响及CD14在LPS激活KC中的意义。　方法　在分离培养大鼠KC的基础上 ,应用免疫组织化学染色、RT PCR等方法分别测定CD14表达的变化、培养KC中上清中TNFα、IL 6和NO浓度。　结果　 (1)不同浓度的LPS使KC中CD14mRNA的表达及其蛋白合成明显增加 ,其表达量与LPS浓度呈剂量依赖性相关 ;(2 )同一浓度的LPS可使KC中CD14mRNA的表达及其蛋白合成明显增加 ,且在 3～ 6h左右达到高峰 ;(3)LPS刺激KC后产生的活性介质能明显上调新培养KC中CD14mRNA的表达及其蛋白合成 ;(4)在血清存在的情况下加入抗CD14单抗或在无血清的情况下单独加入LPS ,可明显降低KCTNFα、IL 6和NO的释放。而后者如果同时加入LBP ,则可明显上调培养KC中的TNFα、IL 6和NO浓度。　结论　 (1)LPS及其刺激KC后产生的活性介质与CD14mRNA的表达及其蛋白合成密切相关 ,并推测在实验 1～ 3h的CD14表达的增强可能主要由LPS引起 ,而此后CD14表达的进一步增强可能与KC释放的细胞因子密切相关 ;(2 )低浓度LPS对KC的激活是CD14依赖的。     

Expression and modulation of a mononuclear phagocyte differentiation antigen (PAM-1) during in vitro maturation of peripheral blood monocytes

Summary Human macrophages obtained by in vitro maturation of peripheral blood monocytes express a surface antigen, PAM-1, recognized by a monoclonal antibody and typical of pulmonary alveolar and tissue macrophages. PAM-1, undetectable in freshly isolated peripheral blood monocytes, was expressed in monocyte-derived macrophages after 3 days of in vitro adherent culture and was maximal after 14–15 days (50%–60% of positive cells). Similar levels of PAM-1 positivity were observed in non-adherent monocyte-derived macrophages suggesting that cell adhesion was not a critical requisite for the expression of this antigen. Bacterial lipolysaccharide and a monocyte chemotactic protein preparation respectively suppressed and upregulated PAM-1 expression in monocyte-derived macrophages. In contrast interferon-γ, although enhancing the levels of class II HLA-DR antigen in monocyte-derived macrophages, did not influence the kinetics of appearance and the levels of PAM-1 in these cells. Thus, expression of PAM-1, which is restricted to certain stages of the monocyte-macrophage differentiation pathway, is also differentially modulated by activation signals, which can be present in the microenvironment of inflammed tissues.     

Fluids reverse the early lipopolysaccharide-induced albumin leakage in rodent mesenteric venules

Objective Volume resuscitation is clinically beneficial in patients with sepsis, but few data exist concerning the effects of fluid administration on early events in the inflammatory process. Vascular permeability, leukocyte rolling and leukocyte adhesion in the rodent mesenteric microcirculation were assessed in vivo using intravital microscopy, and the effect of fluid administration on lipopolysaccharide (LPS)-induced changes recorded.Design Prospective, repeated measures study.Setting University hospital laboratory.Subjects Male Wistar rats in six groups.Interventions All animals underwent intravital microscopic examination of mesenteric post-capillary venules. LPS or vehicle was applied topically. Animals received either no additional fluids, 0.9% saline (16 ml/kg per h) or 5% human albumin (16 ml/kg per h) commencing 30 min prior to LPS/vehicle administration.Measurements and main results Leukocyte rolling, firm adhesion and blood velocity were observed directly. Vascular permeability was assessed using the flux of fluorescently labelled albumin into the interstitium. LPS significantly increased the median (IQR) number of leukocytes rolling and firmly adherent relative to baseline (at 60 min rolling increased from 12.0 (10.3–13.8) to 40.3 (36.0–47.5) cells/min; adhesion increased from 1 (1–2) to 17 (12–26) cells/100 m; n=5, p<0.01). Transvascular albumin flux was significantly increased 45 min after LPS application (p<0.01), but not after vehicle. Administration of either 0.9% saline (n=5) or 5% human albumin (n=6), significantly attenuated LPS-induced increases in albumin flux (p<0.05), leukocyte rolling (p<0.01) and adhesion (p<0.01). Fluid administration did not appear to alter shear rates.Conclusions Pre-emptive volume administration with either saline or albumin prevented early LPS-induced microcirculatory changes by an undefined effect that is unrelated to changes in microvascular flow.Drs. Anning and Finney are supported by grants from the British Heart Foundation.