Ultrastructure Of Tissue Research Articles

Electrospun thymosin Beta-4 loaded PLGA/PLA nanofiber/ microfiber hybrid yarns for tendon tissue engineering application.

Microfiber yarns (MY) have been widely employed to construct tendon tissue grafts. However, suboptimal ultrastructure and inappropriate environments for cell interactions limit their clinical application. Herein, we designed a modified electrospinning device to coat poly(lactic-co-glycolic acid) PLGA nanofibers onto polylactic acid (PLA) MY to generate PLGA/PLA hybrid yarns (HY), which had a well-aligned nanofibrous structure, resembling the ultrastructure of native tendon tissues and showed enhanced failure load compared to PLA MY. PLGA/PLA HY significantly improved the growth, proliferation, and tendon-specific gene expressions of human adipose derived mesenchymal stem cells (HADMSC) compared to PLA MY. Moreover, thymosin beta-4 (Tβ4) loaded PLGA/PLA HY presented a sustained drug release manner for 28 days and showed an additive effect on promoting HADMSC migration, proliferation, and tenogenic differentiation. Collectively, the combination of Tβ4 with the nano-topography of PLGA/PLA HY might be an efficient strategy to promote tenogenesis of adult stem cells for tendon tissue engineering.

FEATURES OFT THE PERIODONTAL TISSUES ULTRASTRUCTURE UNDER CHRONIC PSYCHOEMOTIONAL STRESS

With the help of electron microscopic and morphometric methods, the features of changes in the ultrastructure of periodontal tissues in persons with psychoemotional stresses were studied.It was shown that chronic psychoemotional stress is accompanied in the gum tissue by the development of endothelial and mitochondrial dysfunction with signs of edema and destruction of the capillary endothelium and a violation of the ultrastructure of about 50 % of the mitochondria in the cells.Structural changes were also observed in bone tissue. They testified about the development of destructive processes with the violation of intercellular signaling system and signs of necrotic cells. Such changes in the gum and bone tissues can promote the development of periodontitis in the case of chronic psychoemotional stress and lead to tooth loss.

Hydrogen sulfide exposure induces apoptosis and necroptosis through lncRNA3037/miR-15a/BCL2-A20 signaling in broiler trachea

Hydrogen sulfide (H2S) is an air pollutant, has toxic effects on respiratory tract. However, the underlying mechanisms of H2S induced respiratory toxicity and the roles of long non-coding RNAs (lncRNA) and microRNA (miRNA) in this process remain poorly understood. To clear this, we investigated the change of tracheal tissue ultrastructure and the expression profiles of lncRNAs and miRNAs of chicken trachea exposed to H2S for 42 days. Results showed that H2S exposure triggered apoptosis, necroptosis, and differential expression of 16 lncRNAs and 18 miRNAs in broiler tracheas. The results of LMH cells stimulated by NaHS in vitro also showed the occurrence of apoptosis and necroptosis. LncRNA3037 is down-regulated and miR-15a is up-regulated in tracheal tissue and LMH cells under H2S exposure. Bioinformatics analysis and dual luciferase reporter system showed lncRNA3037 bound directly to miR-15a and negatively regulates each other. A20 and BCL2 are the target genes of miR-15a and negatively regulated by it. Overexpression of miR-15a caused apoptosis and necroptosis and its inhibition partially reversed apoptosis and necroptosis of LMH cells caused by NaHS stimulation and lncRNA3037 knockdown. Taken together, we concluded that H2S exposure mediates apoptosis and necroptosis through lncRNA3037/miR-15/A20-BCL2. These results provide new insights for unveiling the biological effects of H2S in vivo and in vitro.

Optical coherence refraction tomography.

Optical coherence tomography (OCT) is a cross-sectional, micron-scale imaging modality with widespread clinical application. Typical OCT systems sacrifice lateral resolution to achieve long depths of focus for bulk tissue imaging, and hence tend to have better axial than lateral resolution. Such anisotropic resolution can obscure fine ultrastructural features. Furthermore, conventional OCT suffers from refraction-induced image distortions. Here, we introduce optical coherence refraction tomography (OCRT), which extends the superior axial resolution to the lateral dimension, synthesising undistorted cross-sectional image reconstructions from multiple conventional images acquired with angular diversity. In correcting refraction-induced distortions to register the OCT images, OCRT also achieves spatially resolved refractive index imaging. We demonstrate >3-fold improvement in lateral resolution as well as speckle reduction in imaging tissue ultrastructure, consistent with histology. With further optimisation in optical designs to incorporate angular diversity into clinical instruments, OCRT could be widely applied as an enhancement over conventional OCT.

Unobstructed Multiscale Imaging of Tissue Sections for Ultrastructural Pathology Analysis by Backscattered Electron Scanning Microscopy.

Ultrastructural analysis of healthy, diseased, or experimental tissues is essential in diagnostic and investigative pathology. Evaluation of large tissue areas with suborganelle resolution is challenging because biological structures ranging from several millimeters to nanometers in size need to be identified and imaged while maintaining context over multiple scales. Imaging with field emission scanning electron microscopes (FE-SEMs) is uniquely suited for this task. We describe an efficient workflow for the preparation and unobstructed multiscale imaging of tissue sections with backscattered electron scanning electron microscopy (BSE-SEM) for applications in ultrastructural pathology. We demonstrate that a diverse range of tissues, processed by conventional electron microscopy protocols and avoiding the use of mordanting agents, can be imaged on standard glass slides over multiple scales, from the histological to the ultrastructural level, without any visual obstructions. Our workflow takes advantage of the very large scan fields possible with modern FE-SEMs that allow for the acquisition of wide-field overview images which can be explored at the ultrastructural level by digitally zooming into the images. Examples from applications in pulmonary research and neuropathology demonstrate the versatility and efficiency of this method. This BSE-SEM-based multiscale imaging procedure promises to substantially simplify and accelerate ultrastructural tissue analysis in pathology.

Single and joint effects of chronic exposure to chlorpyrifos and glyphosate based pesticides on structural biomarkers in Cnesterodon decemmaculatus

Worldwide freshwater bodies that cross agricultural or urban areas are exposed to mixtures of xenobiotics. In particular, pesticides are usually part of these mixtures and could come into direct or indirect contact with biota and therefore, organisms have to cope with this altered scenario and the detrimental effects of these substances. Commercial formulations of chlorpyrifos and glyphosate, and their mixtures were evaluated using a set of biomarkers in the native fish C. decemmaculatus exposed to relevant environmentally pesticides concentrations. The biomarkers measured were: histopathological indices and tissue ultrastructure in liver and nuclear abnormalities and micronuclei in erythrocytes. During 42 days adult females were exposed to the following concentrations of Clorfox and Roundup Max (chlorpyrifos and glyphosate, respectively): 0.84 nl/l and 8.4 nl/l of Clorfox (CF), 0.2 and 2 mg/l of Roundup Max (RM) and all the combinations of these concentrations. Being the low concentrations of both pesticides environmentally relevant. Nuclear abnormalities of erythrocytes were registered under CF, RM and only one mixture. Histological inflammatory alterations increased in individuals exposed to CF and two mixtures. Finally, some pesticide combinations increased the circulatory alterations in liver. Ultrastructural changes in hepatocytes were registered at all the pesticide treatments. The different biomarker responses showed in the mixtures treatments reflected complex interactions, showing the mixture of the low concentrations of both pesticides (the environmentally relevant), potentiated effects. According to our results the presence of these substances in freshwaters could impose important risks for natural populations by causing deleterious effects on the native fish species C. decemmaculatus.

Deterioration of mitochondrial bioenergetics and ultrastructure impairment in skeletal muscle of a transgenic minipig model in the early stages of Huntington's disease.

ABSTRACTSkeletal muscle wasting and atrophy is one of the more severe clinical impairments resulting from the progression of Huntington's disease (HD). Mitochondrial dysfunction may play a significant role in the etiology of HD, but the specific condition of mitochondria in muscle has not been widely studied during the development of HD. To determine the role of mitochondria in skeletal muscle during the early stages of HD, we analyzed quadriceps femoris muscle from 24-, 36-, 48- and 66-month-old transgenic minipigs that expressed the N-terminal portion of mutated human huntingtin protein (TgHD) and age-matched wild-type (WT) siblings. We found altered ultrastructure of TgHD muscle tissue and mitochondria. There was also significant reduction of activity of citrate synthase and respiratory chain complexes (RCCs) I, II and IV, decreased quantity of oligomycin-sensitivity conferring protein (OSCP) and the E2 subunit of pyruvate dehydrogenase (PDHE2), and differential expression of optic atrophy 1 protein (OPA1) and dynamin-related protein 1 (DRP1) in the skeletal muscle of TgHD minipigs. Statistical analysis identified several parameters that were dependent only on HD status and could therefore be used as potential biomarkers of disease progression. In particular, the reduction of biomarker RCCII subunit SDH30 quantity suggests that similar pathogenic mechanisms underlie disease progression in TgHD minipigs and HD patients. The perturbed biochemical phenotype was detectable in TgHD minipigs prior to the development of ultrastructural changes and locomotor impairment, which become evident at the age of 48 months. Mitochondrial disturbances may contribute to energetic depression in skeletal muscle in HD, which is in concordance with the mobility problems observed in this model.This article has an associated First Person interview with the first author of the paper.

Ultrastructural condition of rats periodontal tissue in opioid influence during two weeks and after its four-week withdrawal on correction

Given that the dental status of drug addicts is burdened with numerous diseases of the tissues and organs of the oral cavity, the issues of developing an optimal scheme of therapeutic tactics for the purpose of restoring their trophic and balance of the oral microflora against opioid background remain relevant in modern periodontology. The aim of the study was to investigate the ultrastructure of periodontal tissues with experimental two-week opioid action and after its abolition for four weeks under conditions of complex medical corrective action. The study material was white male rats (22) of reproductive age (4.5-6 months), Wistar line, with an average body weight of 200 g. The animals were injected with nalbuphine for two weeks, the dose was 0.212 mg/kg and its subsequent withdrawal for four weeks. In order to correct pathological changes arising from the action of opioids in periodontal tissues, pentoxifylline and the antibiotic ceftriaxone were used. Pentoxifylline was administered intramuscularly daily for four weeks after opioid withdrawal (3-6 weeks) at a dose of 2.857 mg/kg. Ceftriaxone was administered once for 11 days at the end of the experiment (5-6 weeks) at a dose equivalent to rat (2.857 mg/kg). Periodontal tissue sampling was performed in the area of the papilla, followed by ultrastructural examination. Submicroscopically found that the structural components of the periodontium have minor changes, their organization is close to normal. The ultrastructure of all sections of the epithelial lining of the mucosa is characterized by a layered arrangement of cells. In epitheliocytes, part of the nuclei has invaginations of the nuclear membrane, indicating their functional activity, clear outlines of compact nucleolus and plasmalemma. In the cytoplasm, most organelles are virtually unchanged, in the mitochondria there are cristae, clearly identified tonofilaments, desmosomal contacts and the basement membrane. Plasmalemma contours are clear, the intercellular contacts are preserved, and the individual intercellular regions appear thickened. The periodontium is represented by well-ordered collagen fiber bundles, the cellular components are unchanged. The detected submicroscopic structure of fibroblasts indicates their synthetic activity aimed at updating the intercellular substance of connective tissue. Electron microscopic studies of the hemocapillaries of the mucous membrane of the gums of animals of this group showed that in their wide lumens there are formed blood elements, mainly erythrocytes. The nuclei of the endothelial cells have an ellipsoidal shape, small invasions of nuclear membrane, clear nuclear membranes, organelles are few. Perivascular spaces without signs of edema. Venules are unaltered, have wide lumens, cytoplasmic portions of endothelial cells are not wide, their nuclear parts protrude into the lumen, the basement membrane is thickened in places. Thus, sub-microscopically established that when canceling opioid analgesic and drug correction at the end of the two-week action of opioid there are signs of positive dynamics in the structural components of periodontium, which is explained by the pathogenic reasonableness of pentoxifylline when disturbed by the opioid analgesia and by medication of the opioid analgesia and medication. effect on the ultrastructural and functional organization of periodontal tissues.

Fenpropathrin induces testicular damage, apoptosis, and genomic DNA damage in adult rats: Protective role of camel milk

Fenpropathrin (FNP) is a member of the synthetic pyrethroids. Herein, the present study was conducted to investigate, for the first time, the potentially harmful effects of FNP on the reproductive system of male rats. In addition, the prophylactic or concurrent influence of camel milk (CM) was assessed. Adult male rats were divided into five groups; control, vehicle control (oil), CM (2ml/rat/day), FNP (15mg/kg bwt/60 days), CM/FNP (prophylaxis) and FNP /CM (co-treated) groups. Sperm morphology, count, serum testosterone (TES), luteinizing hormone (LH) and follicle-stimulating hormone (FSH), thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC), superoxide dismutase (SOD), testicular enzymes, and comet assay analysis were estimated. In addition, histopathology, the ultrastructure of testicular tissue and apoptosis were evaluated. Reduced body weight and gonadosomatic index were observed in the FNP exposed group. TES, LH, FSH were markedly declined following FNP treatment. SOD and TAC concentrations were reduced while PC and TBARS were significantly elevated in FNP group indicating oxidative stress. Furthermore, FNP induced DNA damage and apoptosis in the testis which was evidenced histopathologically and by electron microscope examination. CM significantly counteracted FNP reprotoxic effects, particularly at the prophylactic routine (CM/FNP) than the co-exposure (FNP/CM) one. Conclusively, these findings verified that CM could be a potential candidate therapy against FNP reprotoxic impacts.

Decellularized ECM-derived bioinks: Prospects for the future.

Decellularization aims to remove cells from tissue ultrastructure while preserving the mechanical and biological properties, which makes the decellularized extracellular matrix (dECM) an appropriate scaffold for tissue engineering applications. Three-dimensional (3D) bioprinting technology as a reproducible and accurate method can print the combination of ECM and autologous cells layer by layer to fabricate patient based cell-laden structures representing the intrinsic cues of natural ECM. This review defines ECM, classifies decellularization agents and techniques, and explains different sources of ECM. Then, bioprinting techniques, bioink concept, applications of dECM bioinks, and finally the future perspectives of 3d bioprinting technology are discussed.

Modulations of Histone Deacetylase 2 Offer a Protective Effect through the Mitochondrial Apoptosis Pathway in Acute Liver Failure.

The purpose of this study was to investigate the modulation of histone deacetylase 2 (HDAC2) on mitochondrial apoptosis in acute liver failure (ALF). The cellular model was established with LO2 cells stimulated by tumor necrosis factor alpha (TNF-α)/D-galactosamine (D-gal). Rats were administrated by lipopolysaccharide (LPS)/D-gal as animal model. The cell and animal models were then treated by HDAC2 inhibitor CAY10683. HDAC2 was regulated up or down by lentiviral vector transfection in LO2 cells. The mRNA levels of bcl2 and bax were detected by real-time PCR. The protein levels of HDAC2, bcl2, bax, cytochrome c (cyt c) in mitochondrion and cytosol, apoptosis protease activating factor 1 (apaf1), caspase 3, cleaved-caspase 3, caspase 9, cleaved-caspase 9, acetylated histone H3 (AH3), and histone H3 (H3) were assayed by western blot. Apoptosis was detected by flow cytometry. The serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBIL) levels were also assayed. The openness degree of the mitochondrial permeability transition pore (MPTP) was detected by ultraviolet spectrophotometry. The apoptosis of hepatocytes in liver tissues was determined by tunnel staining. The liver tissue pathology was detected by hematoxylin eosin (HE) staining. The ultrastructure of liver tissue was observed by electron microscopy. Compared with cell and rat model groups, the bax mRNA level was decreased, and bcl2 mRNA was increased in the CAY10683 treatment group. The protein levels of HDAC2, bax, cyt c in cytosol, apaf1, cleaved-caspase 3, and cleaved-caspase 9 were decreased, and the apoptosis rate was decreased (P < 0.05), whereas the protein level of bcl2 and cyt c in the mitochondrion was elevated (P < 0.05) in the CAY10683 treatment group. In the HDAC2 down- or upregulated LO2 cells, the mitochondrial apoptosis pathway was inhibited or activated, respectively. After being treated with TNF-α/D-gal in HDAC2 down- or upregulated LO2 cells, the mitochondrial apoptosis pathway was further suppressed or activated, respectively. The MPTP value was elevated in CAY10683-treated groups compared with the rat model group (P < 0.05). Liver tissue pathological damage and apoptotic index in the CAY10683-treated group were significantly reduced. In addition, AH3 was elevated in both cell and animal model groups (P < 0.05). Downregulated or overexpressed HDAC2 could accordingly increase or decrease the AH3 level, and TNF-α/D-gal could enhance the acetylation effect. These results suggested that modulations of histone deacetylase 2 offer a protective effect through the mitochondrial apoptosis pathway in acute liver failure.

Effects of Copper Chlorophylline and Magnesium Chlorophylline on the Humeral Immune Response, Ultrastructural Changes of Midgut and DNA Damage to Culex pipiens Larvae

There are few studies on the effects of copper chlorophylline (Cu-chl) and magnesium chlorophylline (Mg-chl) on the cellular level, physiological parameters and DNA damage to Culex pipiens larvae. These parameters may be conducive to larval death as a result of photosensitisation reaction after feeding on these photosensitisers and being exposed to light. This study focuses on the impact of Cu-chl and Mg-chl on ultrastructural damage and cellular alteration, immune parameters and DNA damage. The results showed a significant change in the phenoloxidase activity as a function of photosensitiser concentrations. The ultrastructure of midgut tissues revealed obvious damages in different cellular levels. There was no significant effect on DNA. So, it can be concluded that Cu-chl and Mg-chl caused C. pipiens larvae death via the physical damage of larval tissues, and the direct effect on biochemical and physiological parameters of larval viability. Healthy DNA molecules, after the larval treatment, reflected no chance for the undesired mutation of the sublethal concentration of Cu-chl and Mg-chl.

Microstructure-based finite element model of left ventricle passive inflation

Isolating the role(s) of microstructural pathological features in affecting diastolic filling is important in developing targeted treatments for heart diseases. We developed a microstructure-based constitutive model of the myocardium and implemented it in an efficient open-source finite element modeling framework to simulate passive inflation of the left ventricle (LV) in a representative 3D geometry based on experimentally measured muscle fiber architecture. The constitutive model was calibrated using previous tissue-level biaxial mechanical test data derived from the canine heart and validated with independent sets of measurements made at both the isolated constituent and organ level. Using the validated model, we investigated the load taken up by each tissue constituent and their effects on LV passive inflation. The model predicts that the LV compliance is sensitive to the collagen ultrastructure, specifically, the collagen fiber azimuthal angle with respect to the local muscle fiber direction and its waviness. The model also predicts that most of the load in the sub-epicardial and sub-endocardial regions is taken up, respectively, by the muscle fibers and collagen fiber network. This result suggests that normalizing LV passive stiffness by altering the collagen fiber network and myocyte stiffness is most effective when applied to the sub-endocardial and sub-epicardial regions, respectively. This finding may have implication for the development of new pharmaceutical treatments targeting individual cardiac tissue constituents to normalize LV filling function in heart diseases. Statement of SignificanceCurrent constitutive models describing the tissue mechanical behavior of the myocardium are largely phenomenological. While able to represent the bulk tissue mechanical behavior, these models cannot distinguish the contribution of the tissue constituents and their ultrastructure to heart function. Although microstructure-based constitutive models can be used to isolate the role of tissue ultrastructure, they have not been implemented in a computational framework that can accommodate realistic 3D organ geometry. The present study addresses these issues by developing and validating a microstructure-based computational modeling framework, which is used to investigate the role of tissue constituents and their ultrastructure in affecting heart function.

Effects of long-term exposure to elevated temperature on Zea mays endosperm development during grain fill.

Cereal yields decrease when grain fill proceeds under conditions of prolonged, moderately elevated temperatures. Endosperm-endogenous processes alter both rate and duration of dry weight gain, but underlying mechanisms remain unclear. Heat effects could be mediated by either abnormal, premature cessation of storage compound deposition or accelerated implementation of normal development. This study used controlled environments to isolate temperature as the sole environmental variable during Zea mays kernel-fill, from 12days after pollination to maturity. Plants subjected to elevated day, elevated night temperatures (38°C day, 28°C night (38/28°C])) or elevated day, normal night (38/17°C), were compared with those from controls grown under normal day and night conditions (28/17°C). Progression of change over time in endosperm tissue was followed to dissect contributions at multiple levels, including transcriptome, metabolome, enzyme activities, product accumulation, and tissue ultrastructure. Integrated analyses indicated that the normal developmental program of endosperm is fully executed under prolonged high-temperature conditions, but at a faster rate. Accelerated development was observed when both day and night temperatures were elevated, but not when daytime temperature alone was increased. Although transcripts for most components of glycolysis and respiration were either upregulated or minimally affected, elevated temperatures decreased abundance of mRNAs related to biosynthesis of starch and storage proteins. Further analysis of 20 central-metabolic enzymes revealed six activities that were reduced under high-temperature conditions, indicating candidate roles in the observed reduction of grain dry weight. Nonetheless, a striking overall resilience of grain filling in the face of elevated temperatures can be attributed to acceleration of normal endosperm development.

Ultrastructure of the lacrimal drainage system in health and disease: A major review

PurposeTo provide a systematic review of the literature on the ultrastructural findings of the lacrimal drainage system in healthy state and in few of the disorders studied so far. MethodsThe authors performed a PubMed search of all articles published with reference to electron microscopic features of the lacrimal drainage pathways. Data captured include demographics, study techniques, scanning or transmission electron microscopic features, presumed or confirmed interpretations and their implications. Specific emphasis was laid on addressing the lacunae and potential directions for future research. ResultsUltrastructural studies have led to better understanding of the lacrimal drainage anatomy-physiology correlations. Cellular interactions between fibroblasts and lymphocytes could form a basis for pathogenesis of punctal stenosis. Ultrastructural characterization of peri-lacrimal cavernous bodies and changes in primary acquired nasolacrimal duct obstruction (PANDO) led to them being partly implicated in its etiopathogenesis. Electron microscopic characterization of the dacryolith core promises insights into their evolution. Ultrastructural tissue effects of mitomycin-C during a DCR surgery has provided potential evidence of its role in cases with high-risk of failure. Lacrimal stent biofilms are common but their clinical implications are currently uncertain. ConclusionUltrastructural exploration of lacrimal drainage system so far has been limited and sparsely explored. The list of unexplored areas is exhaustive. There is a need for the lacrimal Clinician-Scientist to make themselves familiar with techniques and interpretation of electron microscopy to advance the ultrastructural frontier of this science.

Effects of Extremely Low Frequency Electromagnetic Fields and Simultaneous Treatment with Allium Cepa on Biochemical Parameters and Ultrastructure of Ovarian Tissues of Rats

Introduction: This study investigated the effects of extremely low frequency electromagnetic fields (ELF-EMF) (50 Hz, 3 mT) on biochemical parameters of rats’ ovarian tissues and the impact of Allium cepa on the reduction of potential adverse influences of electromagnetic exposure. Material and Methods: In this study 40 female Wistar rats were divided into four groups, including (1) control group (with 3 cc normal saline), (2) ELF-EMF group (exposed to ELF-EMF, 50 Hz), (3) Allium cepa group (received 3 cc Allium cepa), and (4) ELF-EMF and Allium cepa group (exposed to ELF-EMF and simultaneously received Allium cepa daily for 6 weeks. Results: The MDA levels significantly increased in the second group, which were exposed to ELF-EMF and decreased in normal rats that received Allium cepa. Although, SOD, GPx, and CAT activities significantly decreased in ELF-EMF group, the combination treatment with Allium Cepa on exposed rats restored their activities to normal levels. The conduction of transmission electron microscopy study on ELF-EMF group revealed the changes regarding cytoplasmic organelles in the ovarian follicles of exposed rats. Moreover, irregular oocyte with damaged heterochromatic nuclei was observed. In degenerative oocyte, mitochondria lost their cristae Conclusion: The results of the present study suggested that ELF-EMF exposure might cause deleterious effect on ovarian tissues in rats, which may lead to infertility and subfertility. Moreover, using Allium cepa as a nutritional supplement can have beneficial effects in the protection of biological antioxidants and reproductive systems in cases exposed to ELF-EMF.

Interrenal tissue, chromaffin cells and corpuscles of Stannius of Nile tilapia (Oreochromis niloticus).

Twenty-three fishes were used to study the structure and ultrastructure of interrenal tissue, chromaffin cells and corpuscles of Stannius of Nile tilapia. The interrenal tissue and chromaffin cells are present within the head kidney. The interrenal tissue is arranged in the form of highly convoluted cords, bordered by the lining endothelium of the adjacent sinusoids. It has no connective tissue capsule. The cytoplasm of the interrenal cells contains abundance of mitochondria, vacuoles and smooth endoplasmic reticulum, characterizing of steroid-producing tissues. Two types of chromaffin cells; noradrenaline (NA) cells and adrenaline cells (A) could be recognized by light microscope using chromaffin reaction, as well as by electron microscope they could be distinguished depending on the size and electron density of their granules. The corpuscles of Stannius are two in number and located on the dorsal aspect of the tail kidney. Each corpuscle is surrounded by thick connective tissue capsule. The parenchyma is divided into lobules, each of which is surrounded by distinct basal lamina and has a pseudo lumen. Depending on the presence of secretory granules and the relative abundance of cell organelles, three cell types could be recognized; granular cell, agranular cell (Type I) and agranular cell (Type II). In conclusion, the morphological and ultrastructural analysis of the endocrine tissues of the kidney of Nile tilapia has revealed only one type of interrenal cells, two types of chromaffin cells and three staged-cells of Stannius corpuscles.

RETRACTED: Protective effect of down-regulated microRNA-27a mediating high thoracic epidural block on myocardial ischemia-reperfusion injury in mice through regulating ABCA1 and NF-κB signaling pathway

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. An Expression of Concern for this article was previously published while an investigation was conducted (see related editorial: https://doi.org/10.1016/j.biopha.2022.113812). This retraction notice supersedes the Expression of Concern published earlier. Concern was raised about the reliability of the heart images shown in Figure 1A, which appear to contain similar features to those found in other publications, as detailed here: https://pubpeer.com/publications/108A0BE9F52724D6879E23FAE7F361; and here: https://docs.google.com/spreadsheets/d/1r0MyIYpagBc58BRF9c3luWNlCX8VUvUuPyYYXzxWvgY/edit#gid=262337249. Concerns over the provenance of the flow cytometry data in Figure 7A were also raised. The journal requested the corresponding author comment on these concerns and provide the associated raw data. The authors did not respond to this request and therefore the Editor-in-Chief decided to retract the article.

Subcellular distribution of cadmium in a novel potential aquatic hyperaccumulator – Microsorum pteropus

Microsorum pteropus is a novel potential Cd (cadmium) aquatic hyperaccumulator. In the present study, hydroponic experiments were conducted to assess the accumulation and subcellular distribution of Cd in the root, stem and leaf of M. pteropus. SEM (scanning electron microscopy) – EDX (energy dispersive X-ray fluorescence spectrometer) and TEM (transmission electron microscopy) were used to observe the ultrastructure of different tissues under 500 μM Cd exposure. After exposure to 500 μM Cd for 7 days, the root, stem and leaf of M. pteropus can accumulate to be > 400 mg/kg Cd in dry mass with no significant influence on the growth. In the root and leaf of M. pteropus, the Cd was more likely to store in the cell wall fraction. However, Cd in the stem was mainly stored in both the cell wall fraction and the cytoplasm fraction. Under SEM observation and EDX detection, 1) Cd was found to be sequestrated in the epidermis or chelated in the root cells, 2) no significant deposit spots were observed in the stem, 3) Cd was found in the trichome of the leaf, and the sporangium was not damaged. TEM observations revealed 1) possible Cd precipitations in the root cell and 2) no significant ultrastructure variation in the stem, and 3) the chloroplast retained its structure and was not affected by the Cd. M. pteropus showed great capacity for Cd accumulation without influencing growth. In addition, the ultrastructure of all the tissues was not damaged by the Cd. M. pteropus showed a great potential in phytoremediation in heavy metal polluted water solutions, and may provide new directions for the study of resistance mechanisms of aquatic hyperaccumulators.

Eletroacupuncture improves lipid metabolic disorder by regulating hepatic AMPK/p38 MAPK/RRARγ signaling in rats with high-fat diet-induced insulin resistance

To observe the effect of eletroacupuncture (EA) intervention on lipid metabolism and expression of AMP-activated kinase (AMPK), p38 mitogen-activated protein kinase (p38 MAPK) and peroxisome proliferator-activated receptor γ (PPARγ) protein in the liver in rats with insulin resistance (IR), so as to reveal its mechanisms underlying improvement of IR. Forty male SD rats were randomly divided into blank control, model, medication, and EA groups (n＝8 in each). The IR model was established by feeding the rats with high-fat diet for 12 weeks. After successful establishment of model, the rats in the blank control group and model group were fixed in the self-made rat bag without receiving any treatment. The rats in the medication group were treated by gavage of pioglitazone (10 mL/kg). EA (2 Hz /100 Hz, 1 mA) was applied to bilateral "Fenglong"(ST40) and "Sanyinjiao"(SP6) for 20 min, once a day, for continuous 14 days for rats in the EA group. The ultrastructure of the liver tissue was observed by transmission electron microscope (TEM). Blood samples were taken from the abdominal aorta for detecting serum C-peptide (C-P), adiponectin (ADP), leptin (LEP) and resistin (RES) contents using enzyme linked immunosorbent assay (ELISA). The expression levels of AMPK, p38 MAPK and PPARγ proteins in the liver tissue were detected by Western blot. After modeling, the contents of serum C-P, LEP and RES, and the expression of liver p38 MAPK protein were significantly up-regulated (P<0.01, P<0.05), and the content of ADP and expression of AMPK and PPARγ significantly down-regulated in the model group compared with the blank control group (P<0.01). The increased contents of C-P, LEP and RES, and p38 MAPK protein expression and the decreased serum ADP and hepatic AMPK and PPARγ expression levels were completely reversed in both the EA and medication groups relevant to the model group (P<0.01, P<0.05). No significant differences were found between the EA and medication groups in up-regulating the levels of ADP, AMPK and PPARγ and in down-regulating the levels of C-P, LEP, RES and p38 MAPK(P>0.05). Outcomes of TEM showed that morphological structure of liver mitochondria was damaged, including a large number of lipid droplets, being blur in appearance, rupture of partial membrane, dissapearance of partial mitochondrial crests with vacuolus-like appearance and decrease of rough endoplasmic reticulum in the model group, which was relatively milder in both EA and medication groups. EA intervention is able to improve the disorder of lipid metabolism of IR rats, which may be associated with its effects in lowering the activity of fatty acid synthesis-related enzymes and regulating AMPK/p38 MAPK/PPARγ signaling to improve IR in the liver tissue.