An Automated Self‐Similarity Analysis of the Pulmonary Tree of the Sprague–Dawley Rat

We present the results of an automated analysis of the morphometry of the pulmonary airway trees of the Sprague–Dawley rat. Our work is motivated by a need to inform lower‐dimensional mathematical models to prescribe realistic boundary conditions for multiscale hybrid models of rat lung mechanics. Silicone casts were made from three age‐matched, male Sprague–Dawley rats, immersed in a gel containing a contrast agent and subsequently imaged with magnetic resonance (MR). From a segmentation of this data, we extracted a connected graph, representing the airway centerline. Segment statistics (lengths and diameters) were derived from this graph. To validate this MR imaging/digital analysis method, airway segment measurements were compared with nearly 1,000 measurements collected by hand using an optical microscope from one of the rat lung casts. To evaluate the reproducibility of the MR imaging/digital analysis method, two lung casts were each imaged three times with randomized orientations in the MR bore. Diameters and lengths of randomly selected airways were compared among each of the repeated imaging datasets to estimate the variability. Finally, we analyzed the morphometry of the airway tree by assembling individual airway segments into structures that span multiple generations, which we call branches. We show that branches not segments are the fundamental repeating unit in the rat lung and develop simple mathematical relationships describing these structures for the entire lung. Our analysis shows that airway diameters and lengths have both a deterministic and stochastic character. Anat Rec, 2008. © 2008 Wiley‐Liss, Inc.     

MRI assessment of the intra‐carotid route for macrophage delivery after transient cerebral ischemia

The broad aim underlying the present research was to investigate the distribution and homing of bone marrow‐derived macrophages in a rodent model of transient middle cerebral artery occlusion using MRI and ultrasmall superparamagnetic iron oxide (USPIO) to magnetically label bone marrow‐derived macrophages. The specific aim was to assess the intra‐carotid infusion route for bone marrow‐derived macrophage delivery at reperfusion. Fifteen Sprague–Dawley rats sustained 1 h of middle cerebral artery occlusion. USPIO‐labeled bone marrow‐derived macrophages were slowly injected for 5 min immediately after reperfusion in ischemic animals (n = 7), 1 h after the end of surgery in sham animals (n = 5) and very shortly after anesthesia in healthy animals (n = 3). Multiparametric MRI was performed at day 0, just after cell administration, and repeated at day 1. Immunohistological analysis included Prussian blue for iron detection and rat endothelial cell antigen‐1 for endothelium visualization. Intra‐carotid cell delivery brought a large number of cells to the ipsilateral hemisphere of the brain, as seen on both MRI and immunohistology. However, it was associated with high mortality (50%). The study of sham animals demonstrated that intra‐carotid cell delivery could induce ischemic lesions and may thus favor additional brain damage. The present study highlights severe drawbacks to the intra‐carotid delivery of macrophages at the time of reperfusion in this rodent model of transient cerebral ischemia. Multiparametric MRI appears to be a method of choice to monitor longitudinally the effects of cell infusion, allowing the assessment of both cell fate with the help of magnetic labeling and of potential tissue damage. Copyright © 2012 John Wiley & Sons, Ltd.     

Effect of Prolactin and Bromocriptine on the Population of Prostate Neuroendocrine Cells from Intact and Cyproterone Acetate‐Treated Rats: Stereological and Immunohistochemical Study

This work deals with the quantification of serotonin‐immunoreactive prostate neuroendocrine cells (NECs) in rats exposed to prolactin in normal, cyproterone acetate‐exposed, and bromocriptine‐exposed animals to establish the possible influence of prolactin with or without androgenic blockade on this cell population. Thirty male peripubertal Sprague‐Dawley rats were grouped as controls (CT) and those treated with cyproterone acetate (CA), cyproterone acetate plus prolactin, cyproterone acetate plus bromocriptine, prolactin (PL), and bromocriptine (BC). The volume of ductal epithelium (Vep) and total number (NSER) of the NECs serotonin‐immunoreactive were measured. NECs were detected in the periurethral ducts. Compared to CT, Vep was increased in PL and BC and NSER was decreased in CA and increased in the prolactin or bromocriptine groups. The androgenic blockade decreases NSER in rat prostate; PL induces in normal and cyproterone acetate‐treated rats the increase of NSER; and BC exerts a local effect over the prostate similar to that described for PL. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

Acute intermittent hypoxia induces phrenic long-term facilitation which is modulated by 5-HT1A receptor in the caudal raphe region of the rat

Obstructive sleep apnoea (OSA) is characterized by periods of upper airway collapse accompanied by repeated episodes of hypoxia. In experimental animals repeated bouts of hypoxia may evoke sustained augmentation of phrenic nerve activity, known as phrenic long‐term facilitation (pLTF). This form of physiological compensation might contribute to stable breathing, minimizing the occurrence of apnoeas and/or hypopnoeas during sleep in patients with OSA. Serotonin (5‐HT) has been shown to modulate respiratory neuronal activity, possibly via projections originating in the raphe nuclei. Our model focuses on the effects of 5‐HT_1A receptors blockade by selective antagonist WAY‐100635 into the caudal raphe region on phrenic long‐term facilitation after exposure to acute intermittent hypoxia (AIH) episodes. Adult, male, urethane‐anaesthetized, vagotomized, paralyzed and mechanically ventilated Sprague–Dawley rats were exposed to AIH protocol. Experimental group received microinjection of WAY‐100635 into the caudal raphe nucleus, whereas the control group received saline into the same site. Peak phrenic nerve activity and respiratory rhythm parameters were analysed during five hypoxic episodes, as well as at 15, 30 and 60 min after the end of hypoxias. In the control group, 1 h post‐hypoxia pLTF was developed. Microinjections of selective 5‐HT_1A receptor antagonist WAY‐100635 into the raphe nuclei prior to the AIH protocol prevented induction of pLTF. These results suggest that 5‐HT_1A receptor activation at supraspinal level is important for induction of pLTF, which is suggested to be an important respiratory neuroplasticity model in animal studies that possibly correlates with OSA in humans.     

Pulmonary Architecture in the Conducting Regions of Six Rats

Rats are widely used for studies of pulmonary toxicology and lung disease. Several studies suggest nominal geometric parameters describing the architecture of the rat airway. However, intersubject variance has never been reported due to the huge effort and time to take these manual measurements. In this study, we present statistics of the branching pattern of six healthy male Sprague Dawley rats by automatically analyzing computed tomography images of silicon casts of their airways. Details of branching characteristics and also intersubject variance are presented. In addition, this study shows that mean and standard deviation of many geometric parameters insufficiently represent pulmonary architecture because some, such as diameter‐asymmetry, are not normally distributed. Detailed statistics including inter‐ and intrasubject variance and distribution of the geometric parameters will aid in constructing more realistic airway models for particle transport and studies of normal and abnormal respiratory physiology. Anat Rec, 291:916–926, 2008. © 2008 Wiley‐Liss, Inc.     

Multi‐echo susceptibility‐weighted imaging and histology of open‐field blast‐induced traumatic brain injury in a rat model

Blast‐induced traumatic brain injury is on the rise, predominantly as a result of the use of improvised explosive devices, resulting in undesirable neuropsychological dysfunctions, as demonstrated in both animals and humans. This study investigated the effect of open‐field blast injury on the rat brain using multi‐echo, susceptibility‐weighted imaging (SWI). Multi‐echo SWI provided phase maps with better signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR), making it a sensitive technique for brain injury. Male Sprague‐Dawley rats were subjected to a survivable blast of 180 kPa. The visibility of blood vessels of varying sizes improved with multi‐echo SWI. Reduced signal intensity from major vessels post‐blast indicates increased deoxyhaemoglobin. Relative cerebral blood flow was computed from filtered phase SWI images using inferred changes in oxygen saturation from major blood vessels. Cerebral blood flow decreased significantly at day 3 and day 5 post‐blast compared with that pre‐blast. This was substantiated by the upregulation of β‐amyloid precursor protein (β‐APP), a marker of ischaemia, in the neuronal perikaya of the cerebral cortex, as observed by immunofluorescence, and in the cortical tissue by western blot analysis. Our findings indicate the presence of brain ischaemia in post‐blast acute phase of injury with possible recovery subsequently. Our results from cerebrovascular imaging, histology and staining provide an insight into the ischaemic state of the brain post‐blast and may be useful for prognosis and outcome. Copyright © 2015 John Wiley & Sons, Ltd.     

Distance‐based Permutation of Inter‐Meal Differences as a Sensitive Test of Temporomandibular Joint Nociception in Rats

We compare nonparametric permutation method using intra‐meal rate as endpoint with existing ANOVA method that uses average daily meal duration as an endpoint for detection of chronic pain in Sprague‐Dawley rats. Nociception following bilateral temporomandibular joint (TMJ ) injection of high dose of Complete Freunds Adjuvant (CFA , 250 μg/50 μL per side) could be detected in young adult male Sprague‐Dawley rats using average daily meal durations as a measure of nociception for up to 19 days (Kramer, Kerins, Schneiderman & Bellinger, Physiology & Behavior , 99, 2010; 669) using ANOVA and multiple comparison range tests. In this study, we reanalyzed the data using a nonparametric permutation procedure based on absolute differences between intra‐meal feeding rate curves. In addition to that experiment, we injected bilaterally the TMJ of naive rats with either a low‐dose CFA (15 μg/50 μL per side, n  = 6) or saline (50 μL of 0.9%, n  = 4) and monitored the animals for 7 days. The permutation test of the intra‐meal feeding rate detected the presence of nociception in the high‐dose CFA treatment group for up to 40 days or twice as long as when using ANOVA on average daily meal durations. The permutation method also detected the low‐dose CFA ‐induced nociception with ten times lower p‐ values and for several days longer than ANOVA of changes in meal durations. CFA ‐induced injury resulted in even reduction in intra‐meal feeding rate and lengthening of the meals in both high‐ and low‐dose CFA ‐injected animals. The rate analysis also showed when the rats first started a meal they were experiencing the same level of nociception as at the end of the meal. This demonstrated that intra‐meal chewing itself did not alter the level of nociception. These results suggest that permutation tests based on differences in intra‐meal feeding rates can be used as a sensitive test to determine and study the temporal patterns of TMJ nociception.     

Monoamine oxidase enzymes and oxidative stress in the rat optic nerve: age‐related changes

In this study, age‐related changes in the monoamine oxidases (MAO) were studied in the optic nerve (ON) of both young and aged male rats. The aim of the study was to assess the role of MAO in age‐related changes in the rat ON and explain the mechanisms of neuroprotection mediated by MAO‐B‐specific inhibitors. Fifteen three month old and fifteen 26 month old Sprague–Dawley rats were used. The animals were killed by terminal anaesthesia. Staining of MAO, quantitative analysis of images, biochemical assays and statistical analysis of data were carried out. Samples of the ON were washed in water, fixed in Bowen fluid, dehydrated and embedded in Entellan. Histological sections were stained for MAO‐enzymatic activities. The specificity of the reaction was evaluated by incubating control sections in a medium either without substrate or without dye. The quantitative analysis of images was carried out at the same magnification and the same lighting using a Zeiss photomicroscope. The histochemical findings were compared with the biochemical results. After enzymatic staining, MAO could be demonstrated in the ON fibres of both young and aged animals; however, MAO were increased in the nerve fibres of the elderly rats. These morphological findings were confirmed biochemically. The possibility that age‐related changes in MAO levels may be attributed to impaired energy production mechanisms and/or represent the consequence of reduced energy needs is discussed.     

Quantifying Not Only Bone Loss,but Also Soft Tissue Swelling,in a Murine Inflammatory Arthritis Model Using Micro‐Computed Tomography

In rodent models of inflammatory arthritis, bone erosion has been non‐invasively assessed by micro‐computed tomography (micro‐CT). However, non‐invasive assessments of paw swelling (oedema) are still based on clinical grading by visual evaluation, or measurements by callipers, not always reliable for the tiny mouse paws. The aim of this work was to demonstrate a novel straightforward 3D micro‐CT analysis protocol capable of quantifying not only joint bone erosion, but also soft tissue swelling, from the same scans, in a rodent inflammatory arthritis model. Balb/c mice were divided into two groups: collagen antibody‐induced arthritis (CAIA) and CAIA treated with prednisolone, the latter reflecting an established treatment in human rheumatoid arthritis. Clinical paw scores were recorded. On day 10, front paws were assessed by micro‐CT and histology. Micro‐CT measurements included paw volume (bone and soft tissue together) and bone volume at the radiocarpal joint, and bone volume from the radiocarpal to the metacarpophalangeal joint. Micro‐CT analysis revealed significantly lower paw volume (?36%, P < 0.01) and higher bone volume (+17%, P < 0.05) in prednisolone‐treated CAIA mice compared with untreated CAIA mice. Paw volume and bone volume assessed by micro‐CT correlated significantly with clinical and histological scores (|r| > 0.5, P < 0.01). Untreated CAIA mice showed significantly higher clinical scores, higher inflammation levels histologically, cartilage and bone degradation, and pannus formation, compared with treated mice (P < 0.01). The presented novel micro‐CT analysis protocol enables 3D‐quantification of paw swelling at the micrometre level, along with the typically assessed bone erosion, using the same images/scans, without altering the scanning procedure or using contrast agents.     

Effect of Prolactin on the Population of Epithelial Cells From Ventral Prostate of Intact and Cyproterone Acetate‐Treated Peripubertal Rats: Stereological and Immunohistochemical Study

The interactions between steroid and nonsteroid hormones in the prostate are of special interest during the growth phase of the gland. The purpose of this work is to study the influence of prolactin (PL), with or without androgenic blockade, on epithelial cells from peripubertal rat ventral prostate. Twenty male peripubertal Sprague‐Dawley rats were grouped as controls, or treated with cyproterone acetate (CA), CA plus PL (CA‐PL), or PL. The total number (N total) of epithelial cells, and their labeling indices to proliferative cell nuclear antigen (LI PCNA), apoptosis (LI apoptosis) and androgen receptors (LI AR) were measured. CA and PL treatment significantly decrease the N total, but the LI PCNA was unchanged. We have observed a greater LI apoptosis in pharmacologically castrated animals without PL than in the rats with androgenic blockade with PL. The LI AR does not change with CA treatment in the ventral region, but the PL significantly increases it. Androgenic blockade and PL decrease the number of epithelial cells from the ventral prostate. These changes are not attributable to the decrease of cell proliferation, rather to the increase of epithelial apoptosis. The increase of cells expressing AR after treatment with PL might be attributed to the decrease of testosterone secretion caused by the hyperprolactinemia. PL does not modulate the size of the ventral prostate in prepubertal rats. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc.     

Frequent administration of uric acid extends survival of fasting analbuminemic rats under cold environment

Analbuminemic rats died within 18 h after a rapid decrease of body temperature whereas control Charles River, Wistar, and Sprague Dawley rats survived for 40 h, when the animals were kept at 5 degrees C without food. Five low molecular weight fractions obtained from Sprague Dawley rat sera were administered to analbuminemic rats kept under these conditions. The duration of survival was extended by the administration of two of the fractions. Several characteristics of one of these fractions coincided with those of uric acid, and body temperature of analbuminemic and Sprague Dawley rats increased within 5 min after uric acid administration.     

Effects of exercise training on breast cancer metastasis in a rat model

Exercise training is thought to play a protective role against cancer development and metastasis, either by reducing hormonal stimulation of hormone‐dependent cancers or by reducing the permeability of vascular walls towards invading metastatic cells. The purpose of this work was to evaluate the role of long‐term exercise training in the development and metastasis of breast cancer, in an immune‐competent 1‐methyl‐1‐nitrosourea (MNU) induced rat model. A single MNU dose was administered to Sprague‐Dawley rats at 50 days of age and the rats were subjected to exercise training on a treadmill at 20 m/min, 60 min/day, 5 days/week for 35 weeks. Exercised animals developed slightly less (2.30 ± 1.42) tumours per animal than sedentary animals (2.55 ± 1.44) and did not develop any metastasis, while two pulmonary metastases were observed in the sedentary group. All primary neoplasms and their metastases were positive for oestrogen (ER) α and progesterone (PR) receptors, indicating high hormonal sensitivity. Interestingly, exercise training increased circulating oestrogen levels, thus suggesting that the mechanism might involve either or both of a protective hormone‐independent effect and modulation of tumoural vascularization.     

Architectural and morphological assessment of rat abdominal wall muscles: comparison for use as a human model

The abdominal wall is a composite of muscles that are important for the mechanical stability of the spine and pelvis. Tremendous clinical attention is given to these muscles, yet little is known about how they function in isolation or how they interact with one another. Given the morphological, vascular, and innervation complexities associated with these muscles and their proximity to the internal organs, an appropriate animal model is important for understanding their physiological and mechanical significance during function. To determine the extent to which the rat abdominal wall resembles that of human, 10 adult male Sprague‐Dawley rats were killed and formalin‐fixed for architectural and morphological analyses of the four abdominal wall muscles (rectus abdominis, external oblique, internal oblique, and transversus abdominis). Physiological cross‐sectional areas and optimal fascicle lengths demonstrated a pattern that was similar to human abdominal wall muscles. In addition, sarcomere lengths measured in the neutral spine posture were similar to human in their relation to optimal sarcomere length. These data indicate that the force‐generating and length change capabilities of these muscles, relative to one another, are similar in rat and human. Finally, the fiber lines of action of each abdominal muscle were similar to human over most of the abdominal wall. The main exception was in the lower abdominal region (inferior to the pelvic crest), where the external oblique becomes aponeurotic in human but continues as muscle fibers into its pelvic insertion in the rat. We conclude that, based on the morphology and architecture of the abdominal wall muscles, the adult male Sprague‐Dawley rat is a good candidate for a model representation of human, particularly in the middle and upper abdominal wall regions.     

Growth‐related structural,biochemical, and mechanical properties of the functional bone–cartilage unit

Articular cartilage and subchondral bone act together, forming a unit as a weight‐bearing loading‐transmitting surface. A close interaction between both structures has been implicated during joint cartilage degeneration, but their coupling during normal growth and development is insufficiently understood. The purpose of the present study was to examine growth‐related changes of cartilage mechanical properties and to relate these changes to alterations in cartilage biochemical composition and subchondral bone structure. Tibiae and femora of both hindlimbs from 7‐ and 13‐week‐old (each n = 12) female Sprague‐Dawley rats were harvested. Samples were processed for structural, biochemical and mechanical analyses. Immunohistochemical staining and protein expression analyses of collagen II, collagen IX, COMP and matrilin‐3, histomorphometry of cartilage thickness and COMP staining height were performed. Furthermore, mechanical testing of articular cartilage and micro‐CT analysis of subchondral bone was conducted. Growth decreased cartilage thickness, paralleled by a functional condensation of the underlying subchondral bone due to enchondral ossification. Cartilage mechanical properties seem to be rather influenced by growth‐related changes in the assembly of major ECM proteins such as collagen II, collagen IX and matrilin‐3 than by growth‐related alterations in its underlying subchondral bone structure. Importantly, the present study provides a first insight into the growth‐related structural, biochemical and mechanical interaction of articular cartilage and subchondral bone. Finally, these data contribute to the general knowledge about the cooperation between the articular cartilage and subchondral bone.     

大鼠OSAHS模型的建立及其上气道流场特性的数值模拟分析

目的研究大鼠上气道狭窄动物模型的构建方法及上气道狭窄后气流运动特性。方法将3月龄大鼠32只随机分为对照组和模型组,模型组每只大鼠在麻醉状态下给予0.1 mL透明质酸钠溶液软腭悬雍垂黏膜下注射处理。对照组和模型组在同等环境中饲养3月后,对两组动物分别进行CT扫描及呼吸检测。运用计算流体力学方法对比分析对照鼠和模型鼠上气道流场特性。结果 (1)模型组较对照组鼻咽部气道最小截面积明显减少,气道明显狭窄(P<0.05);(2)模型鼠呼吸急促、呼吸周期不稳定、咽腔呼吸波动较强;(3)在呼吸过程中,对照鼠鼻咽气道壁面最大剪应力分布较分散;而模型鼠鼻咽气道壁面最大剪应力分布较集中。结论软腭黏膜下注射透明质酸钠诱发了上气道狭窄,气道狭窄的动物模型与阻塞性睡眠呼吸暂停低通气综合征(OSAHS)病理学特征类似。上气道狭窄将导致呼吸困难,呼吸周期延长,且剪应力对咽部组织(特别是软腭及悬雍垂)的损伤作用更强,这加剧了咽部组织的力学重建。     

c‐fos gene expression is increased in the paraventricular hypothalamic nucleus of Sprague‐Dawley rats With visceral pain induced by acetic acid without detectable changes of corticotrophin‐releasing factor mRNA: A quantitative approach with an image analysis system

This study is the first of its kind to demonstrate that c‐Fos immunoreactivity (ir) together with c‐fos mRNA in their immediately adjacent tissue sections of a discrete brain region can be reliably measured. The c‐fos gene expression in the paraventricular hypothalamic nucleus (PVN) of Sprague‐Dawley rats for an animal model for visceral or somatovisceral pain induced by 2% acetic acid (AA) was used in this study. Specifically, c‐fos mRNA signals were measured by quantitative autoradiography after in situ hybridization using c‐fos oligodeoxynucleotide probe, and c‐Fos‐ir signals were represented by c‐Fos immunostaining, as detected using c‐Fos antibody in a regular immunohistochemistry. Signals from both c‐Fos‐ir and c‐fos mRNA in the PVN were measured from their immediately adjacent cryostat sections. For the measurement of c‐Fos‐ir, it was carried out by reading 10 rectangles (1,000 μm²/rectangle) on each PVN section with c‐Fos immunostaining. Specific signals were obtained from subtracting the nonspecific background signal from the total signals using a computer‐assisted image analysis system. Results indicated that the AA treatment induced a significant increase of both c‐Fos‐ir and c‐fos mRNA in the PVN. Interestingly, there was no increase of corticotrophin‐releasing factor (CRF) mRNA expression in the PVN and central nucleus of the amygdala of Sprague‐Dawley rats subjected to the AA treatment. In summary, this study has demonstrated that c‐Fos‐ir in the PVN with an anatomical resolution can be semiquantitatively measured after immunohistochemistry using an image analysis system, and that increased c‐fos mRNA in the PVN 1 hr after the AA treatment is associated with no changes of the CRF mRNA expression. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

3D Airway Reconstruction Using Visible Human Data Set and Human Casts with Comparison to Morphometric Data

Realistic airway geometry is required for accurate biomechanical modeling, particle deposition predictions and ultimately risk assessment and inhaled drug delivery protocols. Morphometric studies to date provide data for specific anatomical locations or for more generational average data for the entire lung. In an attempt to provide a realistic geometry representative of a typical human, the National Institute of Health (NIH) Visible Human (VH)^® female data set was reconstructed and compared to available morphometric data from the literature. The reconstructed NIH VH female airway model extended from just distal to the larynx down through the fifth generation of bronchial passageways. Casting and scanning techniques were used to create the upper airway geometries so that the model could be used realistically for oral exposure. Each reconstruction stage was examined to show the loss of data during segmentation, decimation, and smoothing processes. The resulting dimensions of the complete female model were consistent with morphometric data from the literature, indicating that the model is a reasonable representation of an adult female that could be used for biomechanical modeling. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc.     

高浓度臭氧暴露法建立大鼠哮喘模型

目的评价用卵蛋白（OVA）叠加高浓度臭氧（O3）暴露方法建立大鼠严重支气管哮喘模型的方法。方法随机数表法将30只sD大鼠分为正常组、卵蛋白激发组（OVA组）及卵蛋白叠加臭氧暴露组（OVA／O3）。采用OVA腹腔注射致敏,结合OVA持续雾化吸入和臭氧暴露方法,建立重度哮喘模型。观察大鼠哮喘发作期间症状,苏木素-伊红（HE）染色观察大鼠肺组织形态变化及炎症细胞浸润情况。采用免疫组化方法检测NF—κBp65亚基表达变化。结果以OVA激发期间OVA／O3大鼠出现最严重哮喘症状;HE染色结果显示OVA组及OVA／O3组有明显嗜酸性粒细胞浸润,并伴有支气管上皮细胞脱落,OVA／O3现象最为明显。p65在肺组织中的表达以平均光密度（IODmean）计分别为：正常组（0．0146±0．0013）,OVA组（0．2502±0．0009）,OVA／03（0．4240±0．0011）,两模型组显著高于正常组,差异有统计学意义（P〈0．01）,OVA／O3组亦显著高于OVA组（P〈0．01）。结论用臭氧暴露结合OVA致敏方法成功建立重度哮喘大鼠模型。     

Virtual tissue alignment and cutting plane definition – a new method to obtain optimal longitudinal histological sections

Histomorphometric evaluation of the buccal aspects of periodontal tissues in rodents requires reproducible alignment of maxillae and highly precise sections containing central sections of buccal roots; this is a cumbersome and technically sensitive process due to the small specimen size. The aim of the present report is to describe and analyze a method to transfer virtual sections of micro‐computer tomographic (CT)‐generated image stacks to the microtome for undecalcified histological processing and to describe the anatomy of the periodontium in rat molars. A total of 84 undecalcified sections of all buccal roots of seven untreated rats was analyzed. The accuracy of section coordinate transfer from virtual micro‐CT slice to the histological slice, right–left side differences and the measurement error for linear and angular measurements on micro‐CT and on histological micrographs were calculated using the Bland–Altman method, interclass correlation coefficient and the method of moments estimator. Also, manual alignment of the micro‐CT‐scanned rat maxilla was compared with multiplanar computer‐reconstructed alignment. The supra alveolar rat anatomy is rather similar to human anatomy, whereas the alveolar bone is of compact type and the keratinized gingival epithelium bends apical to join the junctional epithelium. The high methodological standardization presented herein ensures retrieval of histological slices with excellent display of anatomical microstructures, in a reproducible manner, minimizes random errors, and thereby may contribute to the reduction of number of animals needed.     

An aversive diet as thiamine‐free food blocks food‐induced release of excitatory amino acids in the accumbens

Aims: As the nucleus accumbens shell plays an important role in the control of eating behaviour, the aim of this study was to evaluate the changes in: (a) the level of aspartic and glutamic acids in the accumbens shell of conditioned rats after the presentation of an aversive diet containing thiamine‐free food; (b) the temperature of interscapular brown adipose tissue, effector of thermogenesis related to food intake. Methods: The concentration of aspartic and glutamic acids in the accumbens shell, and brown adipose tissue temperature were monitored in conditioned male Sprague–Dawley rats before and after the presentation of thiamine‐free food or standard laboratory food. The aspartic and glutamic acids were collected using a microdialysis probe and quantified by HPLC. Food intake was also measured. Results: The results indicated that an intake of standard laboratory food induced an increase in the level of aspartic and glutamic acids, and an elevation in temperature of brown adipose tissue; whereas an intake of thiamine‐free food blocks these increases in the conditioned animals. Conclusion: The thiamine‐free diet modifies the release of excitatory amino acids in the nucleus accumbens of conditioned animals. This diet also affects thermogenesis.