Direct Tracheal Instillation of Solutes into Mouse Lung

Intratracheal instillations deliver solutes directly into the lungs. This procedure targets the delivery of the instillate into the distal regions of the lung, and is therefore often incorporated in studies aimed at studying alveoli. We provide a detailed survival protocol for performing intratracheal instillations in mice. Using this approach, one can target delivery of test solutes or solids (such as lung therapeutics, surfactants, viruses, and small oligonucleotides) into the distal lung. Tracheal instillations may be the preferred methodology, over inhalation protocols that may primarily target the upper respiratory tract and possibly expose the investigator to potentially hazardous substances. Additionally, in using the tracheal instillation protocol, animals can fully recover from the non-invasive procedure. This allows for making subsequent physiological measurements on test animals, or reinstallation using the same animal. The amount of instillate introduced into the lung must be carefully determined and osmotically balanced to ensure animal recovery. Typically, 30-75 μL instillate volume can be introduced into mouse lung.Download video file.^{(31M, mov)}     

Measurement of the Pressure-volume Curve in Mouse Lungs

In recent decades the mouse has become the primary animal model of a variety of lung diseases. In models of emphysema or fibrosis, the essential phenotypic changes are best assessed by measurement of the changes in lung elasticity. To best understand specific mechanisms underlying such pathologies in mice, it is essential to make functional measurements that can reflect the developing pathology. Although there are many ways to measure elasticity, the classical method is that of the total lung pressure-volume (PV) curve done over the whole range of lung volumes. This measurement has been made on adult lungs from nearly all mammalian species dating back almost 100 years, and such PV curves also played a major role in the discovery and understanding of the function of pulmonary surfactant in fetal lung development. Unfortunately, such total PV curves have not been widely reported in the mouse, despite the fact that they can provide useful information on the macroscopic effects of structural changes in the lung. Although partial PV curves measuring just the changes in lung volume are sometimes reported, without a measure of absolute volume, the nonlinear nature of the total PV curve makes these partial ones very difficult to interpret. In the present study, we describe a standardized way to measure the total PV curve. We have then tested the ability of these curves to detect changes in mouse lung structure in two common lung pathologies, emphysema and fibrosis. Results showed significant changes in several variables consistent with expected structural changes with these pathologies. This measurement of the lung PV curve in mice thus provides a straightforward means to monitor the progression of the pathophysiologic changes over time and the potential effect of therapeutic procedures.     

Instillation and Fixation Methods Useful in Mouse Lung Cancer Research

The ability to instill live agents, cells, or chemicals directly into the lung without injuring or killing the mice is an important tool in lung cancer research. Although there are a number of methods that have been published showing how to intubate mice for pulmonary function measurements, none are without potential problems for rapid tracheal instillation in large cohorts of mice. In the present paper, a simple and quick method is described that enables an investigator to carry out such instillations in an efficient manner. The method does not require any special tools or lighting and can be learned with very little practice. It involves anesthetizing a mouse, making a small incision in the neck to visualize the trachea, and then inserting an intravenous catheter directly. The small incision is quickly closed with tissue adhesive, and the mice are allowed to recover. A skilled student or technician can do instillations at an average rate of 2 min/mouse. Once the cancer is established, there is frequently a need for quantitative histologic analysis of the lungs. Traditionally pathologists usually do not bother to standardize lung inflation during fixation, and analyses are often based on a scoring system that can be quite subjective. While this may sometime be sufficiently adequate for gross estimates of the size of a lung tumor, any proper stereological quantification of lung structure or cells requires a reproducible fixation procedure and subsequent lung volume measurement. Here we describe simple reliable procedures for both fixing the lungs under pressure and then accurately measuring the fixed lung volume. The only requirement is a laboratory balance that is accurate over a range of 1 mg–300 g. The procedures presented here thus could greatly improve the ability to create, treat, and analyze lung cancers in mice.     

10. Purification of Viruses by Cenlrifugation in Gradients of Inert Substances

ABSTRACT

By using a reorienting gradient centrifuge rotor cut from a block of Nylon and fitted with eight septae, it was possible to separate the components of the haemolymph of the mollusc Turbo sarmaticus into three fractions in a sucrose gradient held in the bowl of the rotor. The fractions were (108 and 98)S, 44S and 16-22S. The success of the experiment was due to the large differences in the sedimentation coefficients of the components. When the rotor was applied to the natural mixture of the five viruses of the caterpillars of Nudaurelia cytheria only the main component could be isolated in a pure state. The viruses were separated by isopycnic centrifugation in “self formed” caesium chloride gradients, using a Beckman Model E analytical centrifuge in which a separation cell fitted with a centerpiece with two perforated partitions was used.

Centrifugation in gradients of inert substances is useful for the separation of components in a mixture¹. There are two principles involved in this type of separation. One, termed reorienting gradient centrifugation (reograd) relies on the differences in masses or, better still on the sedimentation coefficients of the different components in the mixture and the second, termed isopycnic centrifugation², on the densities or specific gravities of the different entities.     

静脉注射和气管内滴入博莱霉素诱导小鼠肺纤维化的差异

目的 探讨静脉注射和气管内滴入博莱霉素(BLM)对小鼠肺纤维化形成的差异.方法 8周龄雌性C57BL/6小鼠40只,随机分为静脉注射组(V组)20只、气管内滴入组(I组)20只,分别经尾静脉一次性注射BLM 150 mg/kg和气管内滴入BLM 5 mg/kg.观察每组小鼠生存率、肺组织病理改变及肺组织羟脯胺酸的含量.结果 ① V组和I组小鼠的生存率分别为50%和75%,两者间统计学无显著性差异(P>0.05).②注射处置后28 d,两组小鼠均形成广泛、稳定的间质纤维化病理改变,但I组主要分布在肺门和支气管周围,而V组主要分布在胸膜下及血管周围.肺纤维化病理评分I组与V组之间无显著的统计学差异(P>0.05).③小鼠注射处置后28 d,V组与I组肺羟脯氨酸含量分别为634.4±67.1 μg/g和696.6±41.2 μg/g,两组间无显著的统计学差异(P>0.05).结论 利用BLM静脉注射和气管内滴入制备肺间质纤维化动物模型,纤维化形成的部位存在着一定的差异,而肺间质形成纤维化的程度和病理改变大致相同.     

经鼻滴入博莱霉素致小鼠肺纤维化模型的建立及其病理演变

目的经鼻快速滴入博莱霉素复制小鼠肺纤维化模型,观察肺纤维化模型小鼠的病理形态学改变及其羟脯氨酸含量变化,鉴定肺纤维化模型的成功建立。方法经鼻滴入博莱霉素建立小鼠肺纤维化模型。分别于造模第14天和第28天后,取肺组织行HE染色和天狼猩红染色,取心、肝、脾、肾、脑组织行HE染色,光镜下观察组织病理学变化;造模第28天后用样本碱水解法检测肺组织中羟脯氨酸（HYP）的含量。结果①肺组织病理形态学改变：造模第14天和第28天后模型组小鼠肺泡炎及纤维化程度均明显高于阴性对照组,并且在造模第28天后肺纤维化程度进一步加重;②肺组织中HYP含量：与阴性对照组比较,模型组显著升高（P〈0.05）。结论经鼻滴入博莱霉素可以成功复制小鼠肺纤维化模型,肺纤维化模型小鼠HYP含量升高。     

Lungs of Polypterus and Erpetoichthys

The wall of the asymmetrical saclike lungs of the fishes Polypterus and Erpetoichthys consists of several functionally different tissue layers. Their lumen is lined by a surface epithelium composed of (1) highly attenuated cells, termed pneumocytes I; (2) pneumocytes II with lamellar bodies, presumably indicating surfactant production; (3) mucous cells; and (4) ciliated cells. Underlying the pneumocytes I is a dense capillary net. The thin continuous endothelium of this net, together with the pneumocytes I, constitute the very thin blood-air barrier. The basement membrane of epithelium and endothelium fuse in the area of the blood-air barrier (thickness 210 m?m). Secretory and ciliary cells form longitudinal rows in the epithelium. Below the zone with a gas-exchanging tissue, a layer of connective tissue containing collagen and special elastic fibers occurs. The blood vessels that give rise to or drain the superficial capillary plexus are located in this connective tissue. The outermost layer of the lung consists of muscle cells, a narrow inner zone with smooth muscle cells, and an outer, broader zone with cross-striated muscle cells. The lung is innervated by myelinated and nonmyelinated nerve fibers. The morphology of the gas-exchange tissue in the lungs of these primitive bony fish is fundamentally very similar to that of the lungs of tetrapod vertebrates. The morphologic observations are in close agreement with physiologic data, disclosing well-developed respiratory capacities. Structural simplicity can be regarded as a model from which the lungs of the higher vertebrates derived. In addition to respiratory function, the lungs seem also to have hydrostatic tasks.     

人工膜肺氧合器临床应用研究及发展趋势

本文综述目前我国膜式氧合器临床应用,人工膜肺领域的研究成果和发展趋势。通过问卷调查形式显示我国近年CPB （Cardiopulmonary Bypass,体外循环）技术发展迅速,膜式氧合器应用量逐年升高,应用ECMO（extracorporeal membrane oxygenation, 体外膜肺氧合）辅助循环的比例显著增加。人工膜肺多方面研究进展包括：为新生儿体外循环设计的婴幼儿膜式氧合器,整合 动脉滤过器与超滤设备的小型化氧合器,这些设计可以明显减少体外循环回路整体表面积和预充量,避免CPB 中过度血液稀释, 降低或不用输入红细胞。同时减轻由于血液与人工材料接触诱发的炎性反应。人工膜肺在人工材料改进和结构设计有很显著发 展,通过改进气体交换的人工膜材料,优化结构设计,提高血液抗凝能力和耐受力,设计出如ECMO 可以长时间应用于辅助循环 来延续和支持病人的生命。对膜式氧合器的试验研究的相关进展和展望也会在本文讨论。     

Modulation of GABA Release by Second Messenger Substances and NO in Mouse Brain Stem Slices Under Normal and Ischemic Conditions

GABA is the inhibitory neurotransmitter in most brain stem nuclei. The properties of release of preloaded [³H]GABA were now investigated with slices from the mouse brain stem under normal and ischemic (oxygen and glucose deprivation) conditions, using a superfusion system. The ischemic GABA release increased about fourfold in comparison with normal conditions. The tyrosine kinase inhibitor genistein had no effect on GABA release, while the phospholipase inhibitor quinacrine reduced both the basal and K⁺-evoked release in normoxia and ischemia. The activator of protein kinase C (PKC) 4β-phorbol 12-myristate 13-acetate had no effects on the releases, whereas the PKC inhibitor chelerythrine reduced the basal release in ischemia. When the cyclic guanosine monophosphate (cGMP) levels were increased by superfusion with zaprinast and other phosphodiesterase inhibitors, GABA release was reduced under normal conditions. The NO donors S-nitroso-N-acetylpenicillamine (SNAP) and hydroxylamine (HA) enhanced the basal and K⁺-stimulated release by acting directly on presynaptic terminals. Under ischemic conditions GABA release was enhanced when cGMP levels were increased by zaprinast. This effect was confirmed by inhibition of the release by the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). The NO-producing agents SNAP, HA, and sodium nitroprusside potentiated GABA release in ischemia. These effects were reduced by the NO synthase inhibitor N^G-nitro-l-arginine, but not by ODQ. The results show that particularly NO and cGMP regulate both normal and ischemic GABA release in the brain stem. Their effects are however complex.     

肾综合征出血热病毒T-E抗原的制备及其特性研究

本试验建立了用Tween 80和乙醚处理HFRSV感染鼠脑、肺制备特异性抗原的方法,该抗原具有安全、稳定、特异性好、制备简单的特点,可能是HFRSV抗原的共同组分。     

Grafted Neural Precursors Integrate Into Mouse Striatum,Differentiate and Promote Recovery of Function Through Release of Erythropoietin in MPTP-Treated Mice

Erythropoietin-releasing neural precursor cells (Er-NPCs) are a subclass of subventricular zone-derived neural progenitors, capable of surviving for 6 hr after death of donor. They present higher neural differentiation. Here, Er-NPCs were studied in animal model of Parkinson’s disease. Dopaminergic degeneration was caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine intraperitoneal administration in C57BL/6 mice. The loss of function was evaluated by specific behavioral tests. Er-NPCs (2.5 × 10⁵) expressing the green fluorescent protein were administered by stereotaxic injection unilaterally in the left striatum. At the end of observational research period (2 weeks), most of the transplanted Er-NPCs were located in the striatum, while several had migrated ventrally and caudally from the injection site, up to ipsilateral and contralateral substantia nigra. Most of transplanted cells had differentiated into dopaminergic, cholinergic, or GABAergic neurons. Er-NPCs administration also promoted a rapid functional improvement that was already evident at the third day after cells administration. This was accompanied by enhanced survival of nigral neurons. These effects were likely promoted by Er-NPCs-released erythropoietin (EPO), since the injection of Er-NPCs in association with anti-EPO or anti-EPOR antibodies had completely neutralized the recovery of function. In addition, intrastriatal administration of recombinant EPO mimics the effects of Er-NPCs. We suggest that Er-NPCs, and cells with similar properties, may represent good candidates for cellular therapy in neurodegenerative disorders of this kind.     

Silica Triggers Inflammation and Ectopic Lymphoid Neogenesis in the Lungs in Parallel with Accelerated Onset of Systemic Autoimmunity and Glomerulonephritis in the Lupus-Prone NZBWF1 Mouse

Genetic predisposition and environmental factors influence the development of human autoimmune disease. Occupational exposure to crystalline silica (cSiO₂) has been etiologically linked to increased incidence of autoimmunity, including systemic lupus erythematosus (SLE), but the underlying mechanisms are poorly understood. The purpose of this study was to test the hypothesis that early repeated short-term cSiO₂ exposure will modulate both latency and severity of autoimmunity in the lupus-prone female NZBWF1 mouse. Weekly intranasal exposure to cSiO₂ (0.25 and 1.0 mg) for 4 wk beginning at 9 wk of age both reduced latency and increased intensity of glomerulonephritis. cSiO₂ elicited robust inflammatory responses in the lungs as evidenced by extensive perivascular and peribronchial lymphoplasmacytic infiltration consisting of IgG-producing plasma cells, and CD45R+ and CD3+ lymphocytes that were highly suggestive of ectopic lymphoid tissue (ELT). In addition, there were elevated concentrations of immunoglobulins and the cytokines MCP-1, TNF-α and IL-6 in bronchoalveolar lavage fluid. cSiO₂-associated kidney and lung effects paralleled dose-dependent elevations of autoantibodies and proinflammatory cytokines in plasma. Taken together, cSiO₂-induced pulmonary inflammation and ectopic lymphoid neogenesis in the NZBWF1 mouse corresponded closely to systemic inflammatory and autoimmune responses as well as the early initiation of pathological outcomes in the kidney. These findings suggest that following airway exposure to crystalline silica, in mice genetically prone to SLE, the lung serves as a platform for triggering systemic autoimmunity and glomerulonephritis.     

Volumetric and spectroscopic characterizations of glucose-hexokinase association

The binding of D-glucose to hexokinase PII at 25 degrees C and pH 8.7 has been investigated by a combination of ultrasonic velocimetry, high precision densimetry, and fluorescence spectroscopy. The binding of glucose to the enzyme results in significant dehydration of the two interacting molecules, while the intrinsic coefficient of adiabatic compressibility of hexokinase slightly decreases. Glucose-hexokinase association is an entropy-driven process. The favorable change in entropy results from compensation between two large contributions. The binding-induced increase in hydrational entropy slightly prevails over the decrease in the configurational entropy of the enzyme. Taken together, our results emphasize the crucial role of water in modulating the energetics of protein recognition.     

Silver Impregnation of Degenerating Axons; Comparisons of Postoperative Intervals, Fixatives and Staining Methods

By introducing variations in procedures and comparing density and patterns of degeneration exhibited, we found that: (1) in the rat, cat, and monkey, the optimum survival time was about 1 wk; this period yielding the maximum amount of argyrophilic reaction and the most consistent staining among several different parts of the brain. Survival times of up to 3 wk did not seriously impair the interpretation of argyrophilial patterns; (2) some qualitative changes in the nuclear patterns of degeneration suggested that the use of a range of survival times may provide useful data; (3) staining differences and similarities in different neural systems of known connections were about the same in the 3 species of animals; (4) formalin, buffered formalin, and a 4%:1% paraformaldehyde-glutaraldehyde mixture were satisfactory perfusion solutions; however, staining was less intense when the Nauta-Gygax method followed the last fixative mixture; (5) The Fink-Heimer I method yielded more consistent results than did the Fink-Heimer II or the Nauta-Gygax methods.