Proportion Of Collagen Fibers Research Articles

Application effect of a dual release system of androgen and its antagonist in the repair of full-thickness burn wounds in mice

Application effect of a dual release system of androgen and its antagonist in the repair of full-thickness burn wounds in mice

Non-invasive imaging of pathological scars using a portable handheld two-photon microscope.

Pathological scars are a disorder that can lead to various cosmetic, psychological, and functional problems, and no effective assessment methods are currently available. Assessment and treatment of pathological scars are based on cutaneous manifestations. A two-photon microscope (TPM) with the potential for real-time non-invasive assessment may help determine the under-surface pathophysiological conditions in vivo . This study used a portable handheld TPM to image epidermal cells and dermal collagen structures in pathological scars and normal skin in vivo to evaluate the effectiveness of treatment in scar patients. Fifteen patients with pathological scars and three healthy controls were recruited. Imaging was performed using a portable handheld TPM. Five indexes were extracted from two dimensional (2D) and three dimensional (3D) perspectives, including collagen depth, dermo-epidermal junction (DEJ) contour ratio, thickness, orientation, and occupation (proportion of collagen fibers in the field of view) of collagen. Two depth-dependent indexes were computed through the 3D second harmonic generation image and three morphology-related indexes from the 2D images. We assessed index differences between scar and normal skin and changes before and after treatment. Pathological scars and normal skin differed markedly regarding the epidermal morphological structure and the spectral characteristics of collagen fibers. Five indexes were employed to distinguish between normal skin and scar tissue. Statistically significant differences were found in average depth ( t = 9.917, P <0.001), thickness ( t = 4.037, P <0.001), occupation ( t = 2.169, P <0.050), orientation of collagen ( t = 3.669, P <0.001), and the DEJ contour ratio ( t = 5.105, P <0.001). Use of portable handheld TPM can distinguish collagen from skin tissues; thus, it is more suitable for scar imaging than reflectance confocal microscopy. Thus, a TPM may be an auxiliary tool for scar treatment selection and assessing treatment efficacy.

Low-intensity pulsed ultrasound reduces lymphedema by regulating macrophage polarization and enhancing microcirculation.

Background: Conventional therapies reduce lymphedema but do not cure it because they cannot modulate the pathophysiology of secondary lymphedema. Lymphedema is characterized by inflammation. We hypothesized that low-intensity pulsed ultrasound (LIPUS) treatment could reduce lymphedema by enhancing anti-inflammatory macrophage polarization and microcirculation. Methods: The rat tail secondary lymphedema model was established through the surgical ligation of lymphatic vessels. The rats were randomly divided into the normal, lymphedema, and LIPUS treatment groups. The LIPUS treatment (3min daily) was applied 3days after establishing the model. The total treatment period was 28days. Swelling, fibro adipose deposition, and inflammation of the rat tail were evaluated by HE staining and Masson's staining. The photoacoustic imaging system and laser Doppler flowmetry were used to monitor microcirculation changes in rat tails after LIPUS treatment. The cell inflammation model was activated with lipopolysaccharides. Flow cytometry and fluorescence staining were used to observe the dynamic process of macrophage polarization. Results: After 28days of treatment, compared with the lymphedema group, the tail circumference and subcutaneous tissue thickness of rats in the LIPUS group were decreased by 30%, the proportion of collagen fibers and the lymphatic vessel cross-sectional area was decreased, and tail blood flow was increased significantly. Cellular experiments revealed a decrease in CD86+ macrophages (M1) after LIPUS treatment. Conclusion: The transition of M1 macrophage and the promotion of microcirculation could be responsible for the beneficial effect of LIPUS on lymphedema.

Layer-by-Layer Pirfenidone/Cerium Oxide Nanocapsule Dressing Promotes Wound Repair and Prevents Scar Formation

An increase in the levels of reactive oxygen species (ROS) and high expression levels of transforming growth factor-β (TGF-β) in wound tissue are two major problems for wound repair and scar inhibition. Modulation of the wound microenvironment is considered to be able to overcome these issues. Two possible solutions include the use of cerium oxide nanoparticles (CeO2) as an enzyme-like ROS scavenger and pirfenidone (PFD) as an anti-fibrotic drug to inhibit the expression of TGF-β. However, CeO2 is easily adsorbed by biological macromolecules and loses its enzyme-like activity. Furthermore, the intracellular delivery of PFD is difficult. Herein, the layer-by-layer method was used to prepare nanocapsules (NCs) with a sophisticated structure featuring PFD at their core and CeO2 in their shell; these NCs were referred to as PFD/CeO2 NCs. PFD/CeO2 NCs were supposed to efficiently achieve intracellular delivery of PFD and successfully scavenged ROS from the microenvironment. Cellular experiments verified that PFD/CeO2 NCs had good biocompatibility, satisfactory cellular uptake, and favorable ROS-scavenging capacity. To be applied directly to the wound, PFD/CeO2 NCs were then adhered to plasma-etched polylactic acid (PLA) fiber membranes to prepare a new wound dressing. Animal experiments further demonstrated that the dressing accelerated the epithelialization of the wound, reduced the levels of ROS and TGF-β, improved the arrangement and proportion of collagen fibers, and finally, achieved satisfactory wound-repairing and anti-scarring effects. These results provide a new concept for promoting wound repair and preventing scar formation.

Reconstruction of Epidural Fat to Prevent Epidural Fibrosis After Laminectomy in Rabbits.

Laminectomy can effectively decompress the spinal cord and expand the vertebral canal. However, the fibrosis that appears may cause adherence and recompression of the spinal cord or/and nerve root, which may cause failed back syndrome (FBS) and make the reexposure process more difficult. Reconstruction of the epidural fat may be an ideal method to achieve satisfactory results. Thirty-six New Zealand rabbits were randomly divided into three groups: control, extracellular matrix (ECM), and ECM+aMSCs groups. Saline, ECM gel, and ECM+aMSC complex were placed, respectively, at the fifth lumbar vertebrate of the rabbits. Epidural fat and fibrosis formation were detected by magnetic resonance imaging (MRI) and histologically at the 4th, 8th, and 12th weeks. Quantitative RT-PCR was used to detect the expression of interleukin 6 (IL-6) and transforming growth factor β (TGF-β). MRI and Oil Red O staining revealed epidural fat formation at the 12th week in the ECM+aMSCs group. Hematoxylin and eosin staining showed that the numbers of fibroblasts in the ECM gel and ECM+aMSCs groups were less than the control group at the 4th and 8th weeks (p < 0.05). Masson's trichrome staining showed that the proportion of collagen fibers in the ECM gel and ECM+aMSCs group was lower than the control group (p < 0.05). Quantitative RT-PCR showed the expressions of TGF-β and IL-6 were lower in the ECM gel and ECM+aMSCs group than those in the control group (p < 0.05) at the 4th week, but higher at the 8th week. We successfully reconstructed the epidural fat with ECM gel and aMSC complex; additionally, IL-6 and TGF-β cytokines were lower at early stage after laminectomy. Impact statement Our study revealed that epidural fat formed at the 12th week in the extracellular matrix (ECM) plus mesenchymal stem cell (MSC) group after laminectomy in rabbits; additionally, transforming growth factor β (TGF-β) (fibrosis) and interleukin 6 (IL-6) (inflammation) expression was reduced. Thus, we believe that our study makes a significant contribution to the literature because we were able to successfully reconstruct the epidural fat with an ECM gel combined with MSCs and reduce local inflammation.

The effects of exercise training on the lungs and cardiovascular function of animals exposed to diesel exhaust particles and gases

Air pollution has been identified as one of the main environmental risks to health. Since exercise training seems to act as an anti-inflammatory modulator, our hypothesis is that exercise training prevents damage to respiratory and cardiovascular function caused by diesel exhaust particle (DEP) exposure. This study aimed to evaluate whether aerobic exercise training prior to DEP exposure prevents inflammatory processes in the pulmonary and cardiovascular systems. Therefore, BALB/C male mice were or were not submitted to a 10-week exercise training protocol (5×/week, 1 h/d), and after four weeks, they were exposed to DEP in a chamber with 24 μg/m3 PM2.5 or filtered air. Heart rate variability, lung mechanics and bronchoalveolar lavage fluid, cytokines and polymorphonuclear cells in the lung parenchyma were evaluated. Exposure to DEPs reduced heart rate variability and the elastance of the respiratory system and increased the number of cells in bronchoalveolar lavage fluid, as well as macrophages, neutrophils and lymphocytes, the density of polymorphonuclear cells and the proportion of collagen fibres in the lung parenchyma. Additionally, DEP-exposed animals showed increased expression of IL-23 and IL-12p40 (proinflammatory cytokines) and inducible nitric oxide synthase. Exercise training avoided the increases in all these inflammatory parameters, except the elastance of the respiratory system, the amount of collagen fibres and the expression of inducible nitric oxide synthase. Additionally, trained animals showed increased expression of the anti-inflammatory cytokine IL-1ra. Although our data showed a reduction in proinflammatory markers and an increase in markers of the anti-inflammatory pathway, these changes were not sufficient to prevent damage to the lung and cardiovascular function induced by DEPs. Based on these data, we propose that aerobic exercise training prevents the lung inflammatory process induced by DEPs, although it was not sufficient to avoid chronic damage, such as a loss of lung function or cardiovascular events.

The change of bladder compliance and morphology post-spinal cord transection at different time points in rats

Objective To observe the bladder compliance and morphological changes in rats post-suprasacral spinal cord transection at different time points. Methods Seventy-two female Wistar rats were randomly divided into four groups: group A (sham group of 6 weeks); group B (suprasacral spinal cord transaction group of 6 weeks), group C (sham group of 12 weeks), and group D (suprasacral spinal cord transaction group of 12 weeks). Spinal cord transection at T10 level was done in spinal cord transaction groups, while group A and group C underwent sham operaion. Urodynamics was detected at 6th or 12th week after surgery. The changes of smooth muscle, collagen and elastic fibers ratio in the area of bladder wall were observed by hematoxylin-eosin (HE) staining and Verhoeff-Van Gieson staining. Results The rats in spinal cord transaction groups had motor and voiding dysfunction. The bladder compliance in group B was significantly higher than in group A (P<0.05). The bladder compliance in group D was significantly lower than in group C (P<0.05). The morphologic changes of the bladder wall in spinal cord injury groups, including the muscle fibers arranged at random and the increased collagen were aggravated with time. As compared with group B, the bladder compliance in group D was significantly decreased [(0.046±0.023) ml/cmH2O vs. (0.146±0.107) ml/cmH2O (1 cmH2O=0.098 kPa), P<0.01], the proportion of detrusor cross-sectional area was significant decreased [(46.137±4.085)% vs. (55.260±6.873)%, P<0.01], and the proportion of collagen fibers was significantly increased [(19.757±2.071)% vs. (11.104±1.125)%, P<0.01]. Conclusion The bladder compliance in the T10 spinal cord injury rats was increased first, then decreased. The fibrosis of the bladder wall, especially the proportion of collagen fibers was increased, which might be the pathological basis of the reduced bladder compliance. Key words: Spinal cord injury; Neurogenic bladder; Bladder compliance; Collagen fiber

Análisis histológico de la inserción del fascículo superior del músculo pterigoideo externo al disco articular

La inserción del fascículo superior del músculo pterigoideo externo (Pterigoideo Lateral) en el disco articular se presenta a partir del tercio medio de la región central de este y contribuye al desplazamiento del disco y su alteración contribuiría al desplazamiento discal. Sobre la inserción existen diferencias de opinión; unos consideran que solo una pequeña porción de fibras se inserta en la parte anterior de la cápsula y por ende directa e indirectamente al disco; otros investigadores señalan que se encuentra directamente insertado al disco y al cóndilo o solo en el borde anterior de la cápsula y el disco. El objetivo del estudio fue realizar un análisis histológico de la inserción de este músculo para diferenciar el tipo de fibras que llegan al disco articular (proporción de fibras colágenas y fibras musculares) y determinar el tipo de unión entre el músculo y el disco articular. La muestra de este estudio de tipo transversal y exploratorio estuvo constituido por diesiséis preparados anatómicos de articulaciones temporomandibulares, procesándose para su lectura histológica, con colorantes hematoxilina y eosina, Van Guiesson y Mallory, habiéndose encontrado que la mayor proporción de fibras que llegan a insertarse en el disco articular son colágenas y el tipo de unión entre el musculo y el disco articular es en forma intercalada en forma longitudinal.

A hyperoxic lung injury model in premature rabbits: the influence of different gestational ages and oxygen concentrations.

BackgroundMany animal models have been developed to study bronchopulmonary dysplasia (BPD). The preterm rabbit is a low-cost, easy-to-handle model, but it has a high mortality rate in response to the high oxygen concentrations used to induce lung injury. The aim of this study was to compare the mortality rates of two models of hyperoxia-induced lung injury in preterm rabbits.MethodsPregnant New Zealand white rabbits were subjected to caesarean section on gestational day 28 or 29 (full term = 31 days). The premature rabbits in the 28-day gestation group were exposed to room air or FiO2 ≥95%, and the rabbits in the 29-day gestation group were exposed to room air or FiO2 = 80% for 11 days. The mean linear intercept (Lm), internal surface area (ISA), number of alveoli, septal thickness and proportion of elastic and collagen fibers were quantified.ResultsThe survival rates in the 29-day groups were improved compared with the 28-day groups. Hyperoxia impaired the normal development of the lung, as demonstrated by an increase in the Lm, the septal thickness and the proportion of elastic fibers. Hyperoxia also decreased the ISA, the number of alveoli and the proportion of collagen fibers in the 28-day oxygen-exposed group compared with the control 28-day group. A reduced number of alveoli was found in the 29-day oxygen exposed animals compared with the control 29-day group.ConclusionsThe 29-day preterm rabbits had a reduced mortality rate compared with the 28-day preterm rabbits and maintained a reduction in the alveoli number, which is comparable to BPD in humans.

Myocyte Apoptosis in Primary Obstructive Megaureters: The Role of Decreased Vascular and Neural Supply

We compared myocyte apoptosis index, microvessel density and nerve supply as well as muscular and collagen composition in the obstructed ureteral endings of children with primary obstructive megaureter and normal controls. Tissue specimens were obtained during ureteral reimplantation in 16 patients with primary obstructive megaureter. For the control group normal ureteral endings were taken at autopsy from 19 age and sex matched children. In all specimens we determined the myocyte apoptosis index, number of CD31 positive microvessels, alpha-actin positive muscular component and number of nerve terminals. The collagen fibers were also specifically stained. The myocyte apoptosis index was higher in obstructed vesicoureteral junctions (10.14%+/-1.03%) compared to controls (2.11%+/-0.21%, p<0.001). Mean number of vascular elements per microscopic field was lower in ureteral endings of patients with obstructive megaureter compared to controls (p<0.001). The number of nerve endings was also significantly lower in obstructed ureteral endings. There was a negative correlation between the number of microvessels and myocyte apoptosis index in both study groups. In obstructed megaureters the number of nerve endings was also negatively correlated with myocyte apoptosis index but positively correlated with the number of microvessels. In obstructed vesicoureteral junctions the proportion of muscular component was lower and the proportion of collagen fibers was higher compared to normal controls. Positive correlation was found between the myocyte apoptosis index and the percentage of collagenous component in both study groups. Congenital defective vascular development may result in myocyte apoptosis, and reduction of neural elements and muscular components in obstructed vesicoureteral junctions. Subsequent substitution of connective tissue may lead to functional obstruction in primary obstructive megaureter.

Development of pulmonary fibrosis in mice during infection withParacoccidioides brasiliensisconidia

Pulmonary fibrosis is a feared sequelae of paracoccidioidomycosis. We sought to determine if mice exposed to Paracoccidioides brasiliensis conidia would develop pulmonary fibrosis. BALB/c mice were infected intranasally with P. brasiliensis conidia and sacrificed at regular intervals. One lung was sectioned for histopathology and sections were stained with haematoxylin and eosin, trichromic and argentic stains; the other lung was homogenized and cultured to determine the viability of the fungus. One week post-challenge, only small peribronchial foci were apparent. After 4 weeks, reticular fibres appeared disorganized and disrupted. Six to 8 weeks later peribronchial infiltrates were larger and appeared surrounded by reticular fibres; thick collagen I fibres were noticed in the infiltrated areas at this time. On weeks 10-12, infiltrates were confluent and reticular fibres were concentrated around the inflammatory foci; collagenization was apparent. Observations up to 16 weeks revealed diffuse involvement of the lung parenchyma with extensive collagenization. Lung cultures were always positive. We suggest that inhalation of P. brasiliensis conidia induces adverse lung responses leading to changes in the proportion of collagen fibres I and III.

Some anatomical features of the periodontium of the deciduous and permanent dentition in the beagle dog

The present study describes some anatomical characteristics of teeth and periodontal tissues in the deciduous and permanent dentition of the beagle dog. Five animals were used. At the age of 10 weeks (Period A) and 15 months (Period B), respectively, a plaque control period was initiated. At the end of each plaque control period, clinical examinations were performed. Biopsies were obtained from the 02P, 03P (Period A) and P3, P4 (Period B) tooth regions and were examined with the light microscope. Histometric and morphometric measurements were made. The macroscopic and microscopic measurements revealed that marked differences exist between the teeth and the periodontium of the deciduous and the permanent dentition. The permanent premolar erupting into the position of the deciduous premolar was found to be significantly wider and higher than its precursor. Also the shape of the crown of the permanent premolar differed from that of the deciduous premolar. The sinuous contour of the buccal gingival margin was more accentuated in the deciduous than in the permanent dentition. The free gingiva was shorter and the periodontal ligament space was wider in the deciduous than in the permanent dentition. The free gingival unit in the deciduous dentition consisted of a larger volume of epithelium and a smaller volume of connective tissue than the corresponding unit in the permanent dentition. The connective tissue of the deciduous gingiva contained a larger proportion of fibroblasts and a lower proportion of collagen fibres than the corresponding tissue of the permanent gingiva.