Low volume ventilation of pre-injured lungs degrades lung function via stress concentration and progressive alveolar collapse.

Mechanical ventilation can cause ventilation-induced lung injury (VILI). The concept of stress concentrations suggests that surfactant dysfunction-induced microatelectases might impose injurious stresses on adjacent, open alveoli and function as germinal centers for injury propagation. The aim of the present study was to quantify the histopathological pattern of VILI progression and to test the hypothesis that injury progresses at the interface between microatelectases and ventilated lung parenchyma during low positive end-expiratory pressure (PEEP) ventilation. Bleomycin was used to induce lung injury with microatelectases in rats. Lungs were then mechanically ventilated for up to 6 hours at PEEP=1cmH2O and compared to bleomycin treated group ventilated protectively with PEEP=5cmH2O to minimize microatelectases. Lung mechanics were measured during ventilation. Afterwards lungs were fixed at end-inspiration or end-expiration for design-based stereology. Prior to VILI, bleomycin challenge reduced the number of open alveoli (N(alvair,par)) by 29%. No differences between end-inspiration and end-expiration were observed. Collapsed alveoli clustered in areas with a radius up to 56 µm. After PEEP=5cmH2O ventilation for 6 hours, N(alvair,par) remained stable while PEEP=1cmH2O ventilation led to an additional loss of aerated alveoli by 26%, mainly due to collapse, with a small fraction partly edema filled. Alveolar loss strongly correlated to worsening of tissue elastance, quasi-static compliance and inspiratory capacity. The radius of areas of collapsed alveoli increased to 94 µm, suggesting growth of the microatelectases. These data provide evidence that alveoli become unstable in neighborhood of microatelectases which most likely occurs due to by stress concentration-induced local vascular leak and surfactant dysfunction.

The fix is not yet in: recommendation for fixation of lungs within physiologic/pathophysiologic volume range in preclinical pulmonary structure-function studies.

Quantitative characterization of lung structures by morphometric or stereologic analysis of histologic sections is a powerful means of elucidating pulmonary structure-function relations. The overwhelming majority of studies, however, fix lungs for histology at pressures outside the physiologic/pathophysiologic respiratory volume range. Thus valuable information is being lost. In this perspective article, we argue that investigators performing pulmonary histologic studies should consider whether the aims of their studies would benefit from fixation at functional transpulmonary pressures, particular those of end-inspiration and end-expiration. We survey the pressures at which lungs are typically fixed in preclinical structure-function studies; provide examples of conditions that would benefit from histologic evaluation at functional lung volumes; summarize available fixation methods; discuss alternative imaging modalities; and discuss challenges to implementing the suggested approach and means of addressing those challenges. We aim to persuade investigators that modifying or complementing the traditional histologic approach by fixing lungs at minimal and maximal functional volumes could enable new understanding of pulmonary structure-function relations.

Exploring alveolar recruitability using positive end-expiratory pressure in mice overexpressing TGF-ß1: a structure-function analysis.

Pre-injured lungs are prone to injury progression in response to mechanical ventilation. Heterogeneous ventilation due to (micro)atelectases imparts injurious strains on open alveoli (known as volutrauma). Hence, recruitment of (micro)atelectases by positive end-expiratory pressure (PEEP) is necessary to interrupt this vicious circle of injury but needs to be balanced against acinar overdistension. In this study, the lung-protective potential of alveolar recruitment was investigated and balanced against overdistension in pre-injured lungs. Mice, treated with empty vector (AdCl) or adenoviral active TGF-ß1 (AdTGF-ß1) were subjected to lung mechanical measurements during descending PEEP ventilation from 12 to 0 cmH2O. At each PEEP level, recruitability tests consisting of two recruitment maneuvers followed by repetitive forced oscillation perturbations to determine tissue elastance (H) and damping (G) were performed. Finally, lungs were fixed by vascular perfusion at end-expiratory airway opening pressures (Pao) of 20, 10, 5 and 2 cmH2O after a recruitment maneuver, and processed for design-based stereology to quantify derecruitment and distension. H and G were significantly elevated in AdTGF-ß1 compared to AdCl across PEEP levels. H was minimized at PEEP = 5-8 cmH2O and increased at lower and higher PEEP in both groups. These findings correlated with increasing septal wall folding (= derecruitment) and reduced density of alveolar number and surface area (= distension), respectively. In AdTGF-ß1 exposed mice, 27% of alveoli remained derecruited at Pao = 20 cmH2O. A further decrease in Pao down to 2 cmH2O showed derecruitment of an additional 1.1 million alveoli (48%), which was linked with an increase in alveolar size heterogeneity at Pao = 2-5 cmH2O. In AdCl, decreased Pao resulted in septal folding with virtually no alveolar collapse. In essence, in healthy mice alveoli do not derecruit at low PEEP ventilation. The potential of alveolar recruitability in AdTGF-ß1 exposed mice is high. H is optimized at PEEP 5-8 cmH2O. Lower PEEP folds and larger PEEP stretches septa which results in higher H and is more pronounced in AdTGF-ß1 than in AdCl. The increased alveolar size heterogeneity at Pao = 5 cmH2O argues for the use of PEEP = 8 cmH2O for lung protective mechanical ventilation in this animal model.

The IC87201 (a PSD95/nNOS Inhibitor) Attenuates Post- Stroke Injuries.

N-methyl-D-aspartate receptor-dependent excitotoxicity is one of the most important mechanisms underlying stroke injury and the resulting neuronal death. In the present study, in order to reduce post-stroke brain injury and improve behavioral performance, a new molecule named IC87201, which acts as an inhibitor of PSD95/nNOS interaction in the intracellular signaling pathway of NMDA receptors, was administered. Using the middle cerebral artery occlusion (MCAO) technique, 24 adult male rats were subjected to one hour of cerebral ischemia. Animals were randomly divided into sham, MCAO, MCAO + DXM, and MCAO + IC87201 groups, and in the last two groups, intraperitoneal injection of dextromethorphan hydrobromide monohydrate (DXM), as an NMDA antagonist, and IC87201 was performed after ischemia. Neurobehavioral scores were evaluated for seven days, and on the last two days, the rats' memory performance was appraised using the passive avoidance test. On seventh day, the brain tissue was properly prepared for stereological analysis. Stereological studies of the hippocampus CA1 and CA3 regions revealed that changes in the total and infarcted volumes, total number of neurons, non-neurons, and dead neurons are the consequences of cerebral ischemia. Also, following cerebral ischemia, neurobehavioral and memory function impairments which were assessed by modified neurological severity scores (mNSS) and passive avoidance test, were observed. The aforementioned impairments were recovered after administration of IC87201 significantly and more potently than DXM. Based on our findings, IC87201 successfully attenuated post-ischemia damages. Therefore, this molecule can be considered as a new therapeutic approach in future research.

Three-dimensional morphometry of kidney in New Zealand rabbit using unbiased design-based stereology.

The rabbit is widely used as a laboratory animal in experimental models of kidney diseases. This species is also important from a veterinary perspective as a companion animal. Stereology has been accepted as an accurate approach to kidney morphometry. The objective of the present project was to provide normal quantitative stereological parameters for adult rabbit kidneys. The left kidneys of five adult male New Zealand rabbits were used. Isotropic sections were obtained using the orientation method. Total kidney volume was calculated by the Cavalieri principle. The volume fraction of the renal structures was estimated using the point counting system. The lengths of the proximal convoluted tubule (PCT) and distal convoluted tubule (DCT) were calculated using counting frames. The total glomerular number was accounted for using the physical/fractionator technique. The mean glomerular volume was obtained by dividing the total volume of glomeruli by their total number. The total volume of rabbit kidneys calculated was 10.39 ± 1.98 cm3. The fractional volume of the kidney cortex and medulla accounted for 57.79 ± 0.65% and 42.2 ± 0.65%, respectively. The total glomerular volume was 2.18 ± 0.32% of the whole kidney. The total number of glomeruli in the rabbit kidney was estimated as 204.68 ± 12 × 103. The mean glomerular volume measured 1.07 ± 0.12 × 106 µm3. The total length of PCT and DCT was 2.96 ± 0.29 km and 1.38 ± 0.24 km, respectively. These findings can be used as a reference in experimental nephrology research and may help to expand the knowledge of nephrology in mammals by comparing with available data on humans and other species. RESEARCH HIGHLIGHTS: Three-dimensional morphometry of adult rabbit kidney structures was analyzed using quantitative stereology. Total volume of kidney, fractional volume of cortex and medulla, length of renal tubules and number of nephrons were estimated. These three-dimensional morphometrical data can be used as a reference in experimental nephrology research and may help to expand the knowledge of nephrology in mammals.

Foaming and Physico-Mechanical Properties of Geopolymer Pastes Manufactured from Post-Metallurgical Recycled Slag.

This paper presents a research program aimed towards developing a method of producing lightweight, porous geopolymer composites for the construction industry based on industrial wastes. A direct method involving the addition of chemicals is currently most commonly used to produce the porous mineral structure of a geopolymer matrix. This relies on a reaction in a highly alkaline environment of the geopolymer to produce a gas (usually hydrogen or oxygen) that forms vesicles and creates a network of pores. This paper demonstrates the feasibility of producing a slag-based geopolymer paste foamed with aluminum powder, taking into account different parameters of fresh paste production: the mixing duration, its speed and the timing of foaming agent addition. The foaming process of the fresh paste in terms of the volumetric changes and temperature development of the fresh paste during the curing of the material are observed. After hardening, the physical properties (density and porosity) as well as the mechanical parameters (compressive strength and work of damage) are determined for the nine manufactured foamed pastes. Image analysis software was used to assess the porosity distribution of the material across the cross-section of the samples. The results enabled the design of the mixing procedure to be adopted during the manufacture of such composites.

Empagliflozin reduces the adverse effects of diabetes mellitus on testicular tissue in type 2 diabetic Rats: A stereological and biochemical study.

Empagliflozin as an antioxidant decreases blood glucose and insulin resistance in type 2 diabetes mellitus. Base on the empagliflozin antioxidant properties we decided to investigate the its effects on the testis histological changes through stereological techniques and biochemical evaluations in T2 diabetes mellitus rats. Rats were divided into: control, diabetes mellitus (DM, streptozotocin + nicotinamide) and diabetes mellitus + empagliflozin (DM + EMPA, 10 mg/kg/day) groups. 56 days after inducing diabetes mellitus testis histological changes and serum biochemical factors along with the level of Bax, Bcl2 and Nrf2 genes expression in the testicular tissue were assessed. A significant decrease in the mean total volume of testis and its components, the level of Bcl2 and Nrf2 gene expression (p < 0.001) along with a significant increase in the level of IL-6, TNF-α, MDA, Bax gene expression were observed in the DM group compared to the control group (p < 0.001). In the DM + EMPA group, the mean total volume of testis and its components, the level of Bcl2 gene expression (p< 0.01) and Nrf2 (p < 0.001) significantly increased whereas the mean level of IL-6 (p < 0.01), TNF-α (p < 0.001), MDA (p < 0.001), Bax (p < 0.001) gene expression significantly decreased compared to the DM group. Our results showed that empagliflozin, by improving the antioxidant defense system, can reduce testicular inflammation and apoptosis and partly prevent the adverse effects of diabetes mellitus on testicular tissue.

The neuroprotective effects of baobab and black seed on the rat hippocampus exposed to a 900-MHz electromagnetic field.

This study investigated the potential effects on the hippocampus of electromagnetic fields (EMFs) disseminated by mobile phones and the roles of baobab (Adansonia digitata) (AD) and black seed (Nigella sativa) (BS) in mitigating these. Fifty-six male, 12-week-old Wistar albino rats were divided into eight groups of seven animals each. No EMF exposure was applied to the control, AD or BS groups, while the rats in the Sham group were placed in an EMF system with no exposure. A 900-MHz EMF was applied to the EMF+AD, EMF+BS, EMF+AD+BS and EMF groups for 1 hour a day for 28 days. Pyramidal neurons in the hippocampus were subsequently counted using the optical fractionator technique, one of the unbiased stereological methods. Tissue sections were also evaluated histopathologically under light and electron microscopy. The activities of the enzymes catalase (CAT) and superoxide dismutase (SOD) were also determined in blood serum samples. Analysis of the stereological data revealed no statistically significant differences between the EMF and control or sham groups in terms of pyramidal neuron numbers (p>0.05). However, stereological examination revealed a crucial difference in the entire hippocampus between the control group and the AD (p<0.01) and BS (p<0.05) groups. Moreover, exposure to 900-MHz EMF produced adverse changes in the structures of neurons at histopathological analysis. Qualitative examinations suggest that a combination of herbal products such as AD and BS exerts a protective effect against such EMF side-effects.

PGC-1α in the hippocampus mediates depressive-like and stress-coping behaviours and regulates excitatory synapses in the dentate gyrus in mice.

Decreased hippocampal synaptic plasticity is an important pathological change in stress-related mood disorders, including major depressive disorder. However, the underlying mechanism is unclear. PGC-1α, a transcriptional coactivator, is a key factor in synaptic plasticity. We investigated the relationships between changes in hippocampal PGC-1α expression and depressive-like and stress-coping behaviours, and whether they are related to hippocampal synapses. Adeno-associated virus was used to alter hippocampal PGC-1α expression in male C57BL/6 mice. The sucrose preference test and forced swimming test were used to assess their depressive-like and stress-coping behaviours, respectively. Immunohistochemistry and stereology were used to calculate the total number of excitatory synapses in each hippocampal subregion (the cornu ammonis (CA) 1, CA3, and dentate gyrus). Immunofluorescence was used to visualize the changes in dendritic structure. Western blotting was used to detect the expression of hippocampal PGC-1α and mitochondrial-associated proteins, such as UCP2, NRF1 and mtTFAs. Our results showed that mice with downregulated PGC-1α expression in the hippocampus exhibited depressive-like and passive stress-coping behaviours, while mice with upregulated PGC-1α in the hippocampus exhibited increased stress-coping behaviours. Moreover, the downregulation of hippocampal PGC-1α expression resulted in a decrease in the number of excitatory synapses in the DG and in the protein expression of UCP2 in the hippocampus. Alternatively, upregulation of hippocampal PGC-1α yielded the opposite results. This suggests that hippocampal PGC-1α is involved in regulating depressive-like and stress-coping behaviours and modulating the number of excitatory synapses in the DG. This provides new insight for the development of antidepressants.

A novel workflow for unbiased quantification of autophagosomes in 3D in Arabidopsis thaliana roots.

Macroautophagy is often quantified by live imaging of autophagosomes labeled with fluorescently tagged ATG8 protein (FP-ATG8) in Arabidopsis thaliana. The labeled particles are then counted in single focal planes. This approach may lead to inaccurate results as the actual 3D distribution of autophagosomes is not taken into account and appropriate sampling in the Z-direction is not performed. To overcome this issue, we developed a workflow consisting of immunolabeling of autophagosomes with an anti-ATG8 antibody followed by stereological image analysis using the optical disector and the Cavalieri principle. Our protocol specifically recognized autophagosomes in epidermal cells of Arabidopsis root. Since the anti-ATG8 antibody recognizes multiple AtATG8 isoforms, we were able to detect a higher number of immunolabeled autophagosomes than with the FP-AtATG8e marker, that most likely does not recognize all autophagosomes in a cell. The number of autophagosomes per tissue volume correlated with the intensity of autophagy induction. Compared to the quantification of autophagosomes in maximum intensity projections, stereological methods were able to detect the autophagosomes present in a given volume with higher accuracy. Our novel workflow provides a powerful toolkit for unbiased and reproducible quantification of autophagosomes and offers a convenient alternative to the standard of live imaging with FP-ATG8 markers.

Nuclear parcellation and numbers of orexinergic neurons in five species of larger brained birds.

The orexinergic/hypocretinergic system, while having several roles, appears to be a key link in the balance between arousal and food intake. In birds, to date, this system has only been examined anatomically in four species, all with brains smaller than 3.5 g and of limited phylogenetic range. Here, using orexin-A immunohistochemistry, we describe the distribution, morphology, and nuclear parcellation of orexinergic neurons within the hypothalami of a Congo gray and a Timneh gray parrot, a pied crow, an emu, and a common ostrich. These birds represent a broad phylogeny, with brains ranging in size from 7.85 to 26.5 g. Within the hypothalami of the species studied, the orexinergic neurons were organized in two clusters, and a densely packed paraventricular hypothalamic nucleus cluster located within the medial hypothalamus (Hyp), but not contacting the ventricle, and a more loosely packed lateral hypothalamic cluster in the lateral Hyp. Stereological analysis revealed a strong correlation, using phylogenetic generalized least squares regression analyses, between brain mass and the total number of orexinergic neurons, as well as soma parameters such as volume and area. Orexinergic axonal terminals evinced two types of boutons, larger and the smaller en passant boutons. Unlike the orexinergic system in mammals, which has several variances in cluster organization, that of the birds studied, in the present and previous studies, currently shows organizational invariance, despite the differences in brain and body mass, phylogenetic relationships, and life-histories of the species studied.

Mucopolysaccharidosis (MPS IIIA) mice have increased lung compliance and airways resistance, decreased diaphragm strength and no change in alveolar structure.

Mucopolysaccharidosis type IIIA (MPS IIIA) is characterised by neurological and skeletal pathologies caused by reduced activity of the lysosomal hydrolase, sulphamidase, and the subsequent primary accumulation of undegraded heparan sulphate (HS). Respiratory pathology is considered secondary in MPS IIIA and the mechanisms are not well understood. Changes in the amount, metabolism and function of pulmonary surfactant, the substance that regulates alveolar interfacial surface tension and modulates lung compliance and elastance, have been reported in MPS IIIA mice. Here we investigated changes in lung function in 20-week old control and MPS IIIA mice with a closed and open thoracic cage, diaphragm contractile properties and potential parenchymal remodeling. MPS IIIA mice had increased compliance and airway resistance and reduced tissue damping and elastance compared with control mice. The chest wall impacted lung function as observed by an increase in airway resistance and a decrease in peripheral energy dissipation in the open compared to the closed thoracic cage state in MPS IIIA mice. Diaphragm contractile forces showed a decrease in peak twitch force, maximum specific force and the force-frequency relationship but no change in muscle fibre cross-sectional area in MPS IIIA mice compared with control mice. Design-based stereology did not reveal any parenchymal remodelling or destruction of alveolar septa in the MPS IIIA mouse lung. In conclusion, the increased storage of HS which leads to biochemical and biophysical changes in pulmonary surfactant, also affects lung and diaphragm function, but has no impact on lung or diaphragm structure at this stage of the disease.

Comparative study of radioprotective effects of endurance training in irradiation-induced nephropathy of rat model.

OBJECTIVES: Considering the antioxidant properties of endurance training, this study aimed to investigate the effects of endurance training on serum levels of oxidative stress and structural changes in the kidney tissue of rats exposed to X-ray irradiation. METHODS: In this experimental study, 24 rats weighing 220±20 g were randomly divided into four groups (healthy control, healthy with moderate-intensity continuous training, X-ray control, and X-ray with moderate-intensity continuous training). The two groups of rats were irradiated with 4 Gy X-rays. The two training groups also performed moderate-intensity continuous training for 10 weeks. Twenty-four hour after the last training session, the blood serum of rats was collected and kidney tissue was isolated for stereological studies. RESULTS: In this study, X-ray irradiation of the whole body of rats caused a significant increase in kidney volume, cortex volume, interstitial tissue volume, glomerular volume, and serum level of MDA (p≤0.05), but the medulla volume, volume of proximal tubules (total volume, volume of epithelium, and lumen), volume of distal tubules (total volume, volume of epithelium, and lumen), and the length of the proximal and distal tubules had no effect. In addition, TAC and SOD levels were significantly decreased in the radiation control group. Furthermore, performing endurance training in X-ray-irradiated rats significantly reduced kidney volume, cortex volume, glomerular volume, and serum MDA level (p≤0.05). CONCLUSIONS: Moderate-intensity continuous training can improve the rate of destruction of kidney tissue in rats exposed to X-rays by reducing oxidative stress and subsequently increasing antioxidant capacity.

A novel deep learning-based method for automatic stereology of microglia cells from low magnification images.

Microglial cells mediate diverse homeostatic, inflammatory, and immune processes during normal development and in response to cytotoxic challenges. During these functional activities, microglial cells undergo distinct numerical and morphological changes in different tissue volumes in both rodent and human brains. However, it remains unclear how these cytostructural changes in microglia correlate with region-specific neurochemical functions. To better understand these relationships, neuroscientists need accurate, reproducible, and efficient methods for quantifying microglial cell number and morphologies in histological sections. To address this deficit, we developed a novel deep learning (DL)-based classification, stereology approach that links the appearance of Iba1 immunostained microglial cells at low magnification (20×) with the total number of cells in the same brain region based on unbiased stereology counts as ground truth. Once DL models are trained, total microglial cell numbers in specific regions of interest can be estimated and treatment groups predicted in a high-throughput manner (<1 min) using only low-power images from test cases, without the need for time and labor-intensive stereology counts or morphology ratings in test cases. Results for this DL-based automatic stereology approach on two datasets (total 39 mouse brains) showed >90% accuracy, 100% percent repeatability (Test-Retest) and 60× greater efficiency than manual stereology (<1 min vs. ∼ 60 min) using the same tissue sections. Ongoing and future work includes use of this DL-based approach to establish clear neurodegeneration profiles in age-related human neurological diseases and related animal models.

Phenotypically concordant distribution of pick bodies in aphasic versus behavioral dementias.

Pick's disease (PiD) is a subtype of the tauopathy form of frontotemporal lobar degeneration (FTLD-tau) characterized by intraneuronal 3R-tau inclusions. PiD can underly various dementia syndromes, including primary progressive aphasia (PPA), characterized by an isolated and progressive impairment of language and left-predominant atrophy, and behavioral variant frontotemporal dementia (bvFTD), characterized by progressive dysfunction in personality and bilateral frontotemporal atrophy. In this study, we investigated the neocortical and hippocampal distributions of Pick bodies in bvFTD and PPA to establish clinicopathologic concordance between PiD and the salience of the aphasic versus behavioral phenotype. Eighteen right-handed cases with PiD as the primary pathologic diagnosis were identified from the Northwestern University Alzheimer's Disease Research Center brain bank (bvFTD, N = 9; PPA, N = 9). Paraffin-embedded sections were stained immunohistochemically with AT8 to visualize Pick bodies, and unbiased stereological analysis was performed in up to six regions bilaterally [middle frontal gyrus (MFG), superior temporal gyrus (STG), inferior parietal lobule (IPL), anterior temporal lobe (ATL), dentate gyrus (DG) and CA1 of the hippocampus], and unilateral occipital cortex (OCC). In bvFTD, peak neocortical densities of Pick bodies were in the MFG, while the ATL was the most affected in PPA. Both the IPL and STG had greater leftward pathology in PPA, with the latter reaching significance (p < 0.01). In bvFTD, Pick body densities were significantly right-asymmetric in the STG (p < 0.05). Hippocampal burden was not clinicopathologically concordant, as both bvFTD and PPA cases demonstrated significant hippocampal pathology compared to neocortical densities (p < 0.0001). Inclusion-to-neuron analyses in a subset of PPA cases confirmed that neurons in the DG are disproportionately burdened with inclusions compared to neocortical areas. Overall, stereological quantitation suggests that the distribution of neocortical Pick body pathology is concordant with salient clinical features unique to PPA vs. bvFTD while raising intriguing questions about the selective vulnerability of the hippocampus to 3R-tauopathies.

The effects of Garcinia kola and curcumin on the dorsal root ganglion of the diabetic rat after peripheral nerve transection injury.

OBJECTIVE: To test the protective effects of Garcinia kola and curcumin on the ganglion tissues of diabetic rats following the use of autologous vein graft in peripheral nerve transection injury. METHODS: The sciatic nerve on the right side was transected, and anastomosis was performed between the proximal and distal ends using an autologous vein graft. Curcumin and Garcinia kola seed extract were administered daily by oral gavage. The ganglion tissues were harvested after a 90-day waiting period. Sensory neurons in the dorsal root ganglion at the L4 and L5 levels were used for stereological evaluations. Mean sensory neuron numbers were analyzed using a stereological technique. The size of the light and dark neurons was also estimated, and ultrastructural and immunohistochemical evaluations were performed. RESULTS: A statistically significant difference in sensory neuron numbers was observed between the groups with and without Garcinia kola and curcumin applications. The immunohistochemical results showed that the s-100 protein is expressed selectively between cell types. CONCLUSION: The results of this study show that curcumin and Garicinia kola prevented sensory neuron loss in diabetic rats following transection injury to the sciatic nerve.

The assessment of neuronal plasticity following sciatic nerve injuries in rats using electron microscopy and stereological methods.

The transmission of signals to the cell body from injured axons induces significant alterations in primary sensory neurons located in the ganglion tissue, the site of the perikaryon of the affected nerve fibers. Disruption of the continuity between the proximal and distal ends leads to substantial adaptability in ganglion cells and induces macrophage-like activity in the satellite cells. Research findings have demonstrated the plasticity of satellite cells following injury. Satellite cells work together with sensory neurons to extend the interconnected surface area in order to permit effective communication. The dynamic cellular environment within the ganglion undergoes several alterations that ultimately lead to differentiation, transformation, or cell death. In addition to necrotic and apoptotic cell morphology, phenomena such as histomorphometric alterations, including the development of autophagic vacuoles, chromatolysis, cytosolic degeneration, and other changes, are frequently observed in cells following injury. The use of electron microscopic and stereological techniques for assessing ganglia and nerve fibers is considered a gold standard in terms of investigating neuropathic pain models, regenerative therapies, some treatment methods, and quantifying the outcomes of pharmacological and bioengineering interventions. Stereological techniques provide observer-independent and reliable results, which are particularly useful in the quantitative assessment of three-dimensional structures from two-dimensional images. Employing the fractionator and disector techniques within stereological methodologies yields unbiased data when assessing parameters such as number. The fundamental concept underlying these methodologies involves ensuring that each part of the structure under evaluation has an equal opportunity of being sampled. This review describes the stereological and histomorphometric evaluation of dorsal root ganglion neurons and satellite cells following nerve injury models.

A Comparison of Telencephalon Composition among Chickens, Junglefowl, and Wild Galliforms.

INTRODUCTION: Domestication is the process of modifying animals for human benefit through selective breeding in captivity. One of the traits that often diverges is the size of the brain and its constituent regions; almost all domesticated species have relatively smaller brains and brain regions than their wild ancestors. Although the effects of domestication on the brain have been investigated across a range of both mammal and bird species, almost nothing is known about the neuroanatomical effects of domestication on the world's most common bird: the chicken (Gallus gallus). METHODS: We compared the quantitative neuroanatomy of the telencephalon of white leghorn chickens with red junglefowl, their wild counterpart, and several wild galliform species. We focused specifically on the telencephalon because telencephalic regions typically exhibit the biggest differences in size in domesticate-wild comparisons. RESULTS: Relative telencephalon size was larger in chickens than in junglefowl and ruffed grouse (Bonasa umbellus). The relative size of telencephalic regions did not differ between chickens and junglefowl, but did differ in comparison with ruffed grouse. Ruffed grouse had larger hyperpallia and smaller entopallial, nidopallial, and striatal volumes than chickens and junglefowl. Multivariate analyses that included an additional three wild grouse species corroborated these findings: chicken and junglefowl have relatively larger nidopallial and striatal volumes than grouse. Conversely, the mesopallial and hyperpallial volumes tended to be relatively smaller in chickens and junglefowl. CONCLUSION: From this suite of comparisons, we conclude that chickens do not follow a pattern of widespread decreases in telencephalic region sizes that is often viewed as typical of domestication. Instead, chickens have undergone a mosaic of changes with some regions increasing and others decreasing in size, and there are few differences between chickens and junglefowl.

Reduction of Microvessel Number and Length in the Cerebellum of Purkinje Cell Degeneration Mice.

Degenerative effects of nerve tissues are often accompanied by changes in vascularization. In this regard, knowledge about hereditary cerebellar degeneration is limited. In this study, we compared the vascularity of the individual cerebellar components of 3-month-old wild-type mice (n = 8) and Purkinje cell degeneration (pcd) mutant mice, which represent a model of hereditary cerebellar degeneration (n = 8). Systematic random samples of tissue sections were processed, and laminin was immunostained to visualize microvessels. A computer-assisted stereology system was used to quantify microvessel parameters including total number, total length, and associated densities in cerebellar layers. Our results in pcd mice revealed a 45% (p < 0.01) reduction in the total volume of the cerebellum, a 28% (p < 0.05) reduction in the total number of vessels and a lower total length, approaching 50% (p < 0.001), compared to the control mice. In pcd mutants, cerebellar degeneration is accompanied by significant reduction in the microvascular network that is proportional to the cerebellar volume reduction therefore does not change density of in the cerebellar gray matter of pcd mice.

The histomorphological and stereological assessment of rat dorsal root ganglion tissues after various types of sciatic nerve injury.

Peripheral nerve injuries lead to significant changes in the dorsal root ganglia, where the cell bodies of the damaged axons are located. The sensory neurons and the surrounding satellite cells rearrange the composition of the intracellular organelles to enhance their plasticity for adaptation to changing conditions and response to injury. Meanwhile, satellite cells acquire phagocytic properties and work with macrophages to eliminate degenerated neurons. These structural and functional changes are not identical in all injury types. Understanding the cellular response, which varies according to the type of injury involved, is essential in determining the optimal method of treatment. In this research, we investigated the numerical and morphological changes in primary sensory neurons and satellite cells in the dorsal root ganglion 30 days following chronic compression, crush, and transection injuries using stereology, high-resolution light microscopy, immunohistochemistry, and behavioral analysis techniques. Electron microscopic methods were employed to evaluate fine structural alterations in cells. Stereological evaluations revealed no statistically significant difference in terms of mean sensory neuron numbers (p > 0.05), although a significant decrease was observed in sensory neuron volumes in the transection and crush injury groups (p < 0.05). Active caspase-3 immunopositivity increased in the injury groups compared to the sham group (p < 0.05). While crush injury led to desensitization, chronic compression injury caused thermal hyperalgesia. Macrophage infiltrations were observed in all injury types. Electron microscopic results revealed that the chromatolysis response was triggered in the sensory neuron bodies from the transection injury group. An increase in organelle density was observed in the perikaryon of sensory neurons after crush-type injury. This indicates the presence of a more active regeneration process in crush-type injury than in other types. The effect of chronic compression injury is more devastating than that of crush-type injury, and the edema caused by compression significantly inhibits the regeneration process.