Changes In Ultrastructure Of Cells Research Articles

Changes in energy metabolism accompanying pitting in blueberries stored at low temperature

Low-temperature storage and transport of blueberries is widely practiced in commercial blueberry production. In this research, the storage life of blueberries was extended at low temperature, but fruit stored for 30d at 0°C pitted after 2d at room-temperature. Fruit cellular structure and physiological parameters accompanying pitting in blueberries were changed. The objective of this research was to characterise properties of energy metabolism accompanying pitting in blueberries during storage, including adenosine phosphates and mitochondrial enzymes involved in stress responses. Physiological and metabolic disorders, changes in cell ultrastructure, energy content and ATPase enzyme activity were observed in pitting blueberries. Energy shortages and increased activity of phenylalanine ammonia lyase (PAL) and lipoxygenase (LOX) were observed in fruit kept at shelf life. The results suggested that sufficient available energy status and a stable enzymatic system in blueberries collectively contribute to improve chilling tolerance, thereby alleviating pitting and maintaining quality of blueberry fruit in long-term cold storage.

Effect of the secretory leucocyte proteinase inhibitor (SLPI) on Candida albicans biological processes: A therapeutic alternative?

ObjectivesThe aim of this study was to evaluate the effect of SLPI on the growth and biological processes of Candida albicans. MethodsTwo C. albicans strains were used in this study, a clinical isolate resistant to fluconazole (PRI) and a reference strain ATCC 24433. The minimal inhibitory concentration (MIC) was determined according to the CLSI methodology. The influence of SLPI on secreted serine proteinase activities (SSP) was measured by the cleavage of specific substrate, and surface hydrophobicity was determined by the aqueous-hydrocarbon biphasic separation method. Flow cytometry was performed to investigate receptors for SLPI and variations in the cell wall mannoprotein expression. Interaction between yeast and epithelium was assessed using the MA-104 cells lineage. Ultrastructure was analyzed by transmission electron microscopy (TEM). ResultsMIC values were calculated as 18 and 18.9μM for the PRI and ATCC 24433, respectively. SSP activity was reduced by 48.8% by 18μM of SLPI and cell surface hydrophobicity increased by 11.1%. Flow cytometry suggest the existence of SLPI binding sites on the surface of the yeast. Results showed a reduction in the expression of mannoproteins in 20.8% by the cells treated with 80μM of SLPI, and 18μM reduced the adhesion of yeasts to mammalian cells in 60.1%. TEM revealed ultrastructural changes in cells treated with 80μM of SLPI, such as the presence of membrane-like structures within the cytoplasm. ConclusionsSLPI exerts a significant influence on C. albicans viability and biological processes. Considering its constitutive and physiologic features, SLPI may become a promising tool for the development of new methodologies for the treatment and control of candidiasis.

Celecoxib regulates apoptosis and autophagy via the PI3K/Akt signaling pathway in SGC-7901 gastric cancer cells

Gastric cancer, one of the most common malignancies worldwide, typically has a poor prognosis and poor survival rate. Previous studies have investigated the chemopreventive effect of celecoxib. In the present study, the SGC-7901 human gastric cancer cell line was utilized to examine the chemopreventive mechanisms of celecoxib. The inhibition of cell proliferation was determined using MTT assay, cell apoptosis was monitored by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) and flow cytometry, and cell ultrastructural changes were assessed via transmission electron microscopy. The mRNA expression of Akt, caspase-8 and -9 was examined using quantitative reverse-transcription-polymerase chain reaction (qRT-PCR) and p-Akt, procaspase-8 and -9 were analyzed via western blotting. The results showed that celecoxib inhibited the proliferation of SGC-7901 cells in a time- and dose-dependent manner. Additionally, celecoxib induced apoptosis as substantiated by typical apoptotic bodies, autophagosomes and an increased apoptotic rate. It was found that following celecoxib treatment, Akt mRNA expression was not significantly altered, and that p-Akt protein levels decreased in a time- and dose-dependent manner. Additionally, caspase-8 and -9 mRNA expression was significantly increased, while procaspase-8 and -9 protein expression decreased relative to the time- and dose-dependent effects. These results demonstrated that celecoxib induced apoptosis and autophagy of gastric cancer cells in vitro through the PI3K/Akt signaling pathway. Moreover, our findings suggested that celecoxib induces apoptosis in gastric cancer cells through the mitochondrial and death receptor pathways, providing additional understanding regarding the chemopreventive behaviors of celecoxib and its uses in cancer therapy.

Bystander Effect Induced by UVC Radiation in Chinese hamster V79 cells

In past decades, researches on radiation-induced bystander effect mainly focused on ionizing radiation such as α-particle, β-particle, X-ray and γ-ray. But few researches have been conducted on the ability of ultraviolet (UV) radiation-induced bystander effect, and knowledge of UVC-induced bystander effect is far limited. Here, we adopted medium transfer experiment to detect whether UVC could cause bystander effect in Chinese hamster V79 cells. We determined the cell viability, apoptosis rate, chromosome aberration and ultrastructure changes, respectively. Our results showed that: (1) the viability of UVC-irradiated V79 cells declined significantly with the dosage of UVC; (2) similar to the irradiated cells, the main death type of bystander cells cultured in irradiation conditioned medium (ICMs) was also apoptosis; (3) soluble factors secreted by UVC-irradiated cells could induce bystander effect in V79 cells; (4) cells treated with 4 h ICM collected from 90 mJ cm(-2) UVC-irradiated cells displayed the strongest response. Our data revealed that UVC could cause bystander effect through the medium soluble factors excreted from irradiated cells and this bystander effect was a novel quantitative and kinetic response. These findings might provide a foundation to further explore the exact soluble bystander factors and detailed mechanism underlying UVC-induced bystander effect.

The influence of salinity on cell ultrastructures and photosynthetic apparatus of barley genotypes differing in salt stress tolerance

A hydroponic experiment was conducted to elucidate the difference in growth and cell ultrastructure between Tibetan wild and cultivated barley genotypes under moderate (150 mM NaCl) and high (300 mM NaCl) salt stress. The growth of three barley genotypes was reduced significantly under salt stress, but the wild barley XZ16 (tolerant) was less affected relative to cultivated barley Yerong (moderate tolerant) and Gairdner (sensitive). Meanwhile, XZ16 had lower Na+ and higher K+ concentrations in leaves than other two genotypes. In terms of photosynthetic and chlorophyll fluorescence parameters, salt stress reduced maximal photochemical efficiency (F v/F m), net photosynthetic rate (Pn), stomatal conductance (Gs), and intracellular CO2 concentration (Ci). XZ16 showed relatively smaller reduction in comparison with the two cultivated barley genotypes. The observation of transmission electron microscopy found that fundamental cell ultrastructure changes happened in both leaves and roots of all barley genotypes under salt NaCl stress, with chloroplasts being most changed. Moreover, obvious difference could be detected among the three genotypes in the damage of cell ultrastructure under salt stress, with XZ16 and Gairdner being least and most affected, respectively. It may be concluded that high salt tolerance in XZ16 is attributed to less Na+ accumulation and K+ reduction in leaves, more slight damage in cell ultrastructure, which in turn caused less influence on chloroplast function and photosynthesis.

The impact of Interleukin-1β on the structure of human umbilical vein endothelial cells and aquaporin-1 expression

Objective To explore the role of IL-1β in capillary leak syndrome by observing the alterations of AQP-1 expression,apoptosis,and ultrastructural of vascular endothelial cells under the action of IL-1β.Methods Umbilical vein endothelial cells (UVEC) in vitro were randomly allocated into 3 groups:time,concentration,and control.In the time group,UVECs were treated with culture medium containing 20 μg/L IL-1β for3 h(T1),8 h(T2),12 h(T3) and 24 h(T4).In the concentration group,UVECs were treated with culture medium containing 0.2 μg/L(C1),2 μg/L(C2) and 20 μg/L(C3) IL-1β for 24 h.In the control group,UVECs were treated with culture medium without IL-1β for 24 h.The changes of AQP-1 mRNA and protein expression were detected by real-time PCR and Western blot.Apoptosis was detected by flow cytometry,and cell ultrastructural changes were observed by electron microscopy.Results AQP-1 mRNA and protein expression of T1-T4 in the time group and C1-C3 in the concentration group were lower than those of the control group (P ＜ 0.05).The apoptotic rate was increased,and mitochondrial swelling,vacuolar degeneration,karyolysis and necrosis were observed under electron microscopy.These were more pronounced with time or concentration increases.Conclusions IL-1β can cause a decrease of AQP-1 mRNA and protein expression,increase in apoptotic rate and increase in damage to the cells'ultrastructure.This is an important reason for damage to the vascular endothelial barrier and may be associated with capillary leak syndrome. Key words: Capillary leak syndrome; Vascular endothelial barrier; Interleukin-1β ; Aquaporin-1 ; Apoptosis

Changes in cell ultrastructure and morphology of Arabidopsis thaliana roots after coumarins treatment

The ultrastructure and morphology of roots treated with coumarin and umbelliferone as well as the reversibility of the coumarins effects caused by exogenous GA, were studied in <em>Arabidopsis thaliana</em>. Both coumarins suppressed root elongation and appreciably stimulated radial expansion of epidermal and cortical cells in the upper part of the meristem and in the elongation zone. The gibberellic acid applied simultaneously with coumarins decreased their inhibitory effect on root elongation and reduced cells swelling.Microscopic observation showed intensive vacuolization of cells and abnormalities in the structure of the Golgi stacks and the nuclear envelope. The detection of active acid phosphatase in the cytosol of swollen cells indicated increased membrane permeability. Significant abnormalities of newly formed cell walls, e.g. the discontinuity of cellulose layer, uncorrect position of walls and the lack of their bonds with the mother cell wall suggest that coumarins affected the cytoskeleton.

Effects of SSd combined with radiation on inhibiting SMMC-7721 hepatoma cell growth.

BackgroundThe aim of this study was to investigate the effects of Saikosaponin-d (SSd) combined with radiotherapy on SMMC-7721 hepatoma cell lines and its mechanism.Material/MethodsSMMC-7721 hepatoma cell lines are selected in our research. With MTT (methylthiazolyldiphenyl-tetrazolium-bromide) method, the effects of SSd and radiation on inhibiting SMMC-7721 cell growth were investigated. We also used transmission electron microscopy (TEM) to observe ultrastructural changes of cells. Colorimetry methods were used to measure content changes of glutathione (GSH) and malondialdehyde (MDA) in cells.ResultsBoth SSd and radiation inhibited the growth of SMMC-7721 cells. The combination of SSd and radiotherapy had a time-dependent synergistic effect. Radiation caused ultrastructural damage to cells, and the damage was enhanced in combination with SSd. Radiation decreased the GSH content and increased the MDA content in cells, and this effect was suppressed after the intervention of SSd.ConclusionsSSd can inhibit the growth of SMMC-7721 hepatoma cell lines in vitro. Additionally, it significantly enhances the effects of radiation on inhibiting the growth of SMMC-7721 hepatoma cell lines, and up-regulates the antioxidant level after the radiotherapy. Thus, SSd could be an ideal radiotherapy sensitizer for the treatment of liver cancer.

ERK inhibitor U0126 enhanced SDT-induced cytotoxicity of human leukemia U937 cells

This study was to investigate the cell killing effect of chlorin-e6 (Ce6) mediated sonodynamic therapy (SDT) on human leukemia U937 cells and explore the role of ERK signal pathway in the process. The ultrastructure changes of U937 cells induced by ultrasonic irradiation were evaluated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The viability of cells was evaluated by viacount assay. Apoptosis was analyzed using flow cytometer as well as fluorescence microscopy with 4'-6-diamidino-2-phenylindole (DAPI) staining. Western blotting was used to analyze the expression of mitogen-activated protein kinase (MAPK). Intracellular reactive oxygen species (ROS) and mitochondria membrane potential (MMP) levels were also analyzed by flow cytometer after exposure. Our experiments showed that several distinct sonochemical effects were found after Ce6-mediated SDT treatment. Western blotting analysis indicated that the MAPK were activated. Especially, pre-treatment with ERK inhibitor U0126 could additionally enhance SDT-induced cell viability loss, early- and late-apoptotic rate, chromatin condensation, DNA fragmentation and caspase-3 activation. Besides, a mass of ROS accumulation and a conspicuous loss of mitochondrial membrane potential were detected in U937 cells. These findings suggested ERK signal pathway may deliver a survival signal which counteracts SDT-induced cell death, while combination with U0126 could significantly potentiate the SDT-induced cytotoxic effect in U937 cells.

Cadmium‐induced cell death in BY‐2 cell culture starts with vacuolization of cytoplasm and terminates with necrosis

Cadmium is a potent inducer of programmed cell death (PCD) in plants but the morphological changes in cells exposed to cadmium are poorly characterized. Using light and transmission electron microscopy (TEM) we have investigated the changes in ultrastructure of tobacco BY-2 cells treated with 50 µM CdSO4. The cadmium-induced alterations in cell morphology occurred gradually over a period of 3-4 days and the first stages of the response resembled vacuolar type of cell death. The initial formation of numerous small cytoplasmic vacuoles and dilation of endoplasmic reticulum was followed first by fusion of smaller vacuoles with each other and with big vacuoles, and then by the appearance of autophagic vacuoles containing autophagic bodies. The final stages of cell death were accompanied by necrotic features including loss of plasmalemma integrity, shrinkage of the protoplast and unprocessed cellular components. In addition, we observed a gradual degradation of nuclear material. Our results demonstrate that cadmium-induced plant cell death is a slow process featuring elements of vacuolar cell death and terminating with necrosis.

Exposure of Escherichia coli ATCC 12806 to Sublethal Concentrations of Food-Grade Biocides Influences Its Ability To Form Biofilm, Resistance to Antimicrobials, and Ultrastructure

Escherichia coli ATCC 12806 was exposed to increasing subinhibitory concentrations of three biocides widely used in food industry facilities: trisodium phosphate (TSP), sodium nitrite (SNI), and sodium hypochlorite (SHY). The cultures exhibited an acquired tolerance to biocides (especially to SNI and SHY) after exposure to such compounds. E. coli produced biofilms (as observed by confocal laser scanning microscopy) on polystyrene microtiter plates. Previous adaptation to SNI or SHY enhanced the formation of biofilms (with an increase in biovolume and surface coverage) both in the absence and in the presence (MIC/2) of such compounds. TSP reduced the ability of E. coli to produce biofilms. The concentration of suspended cells in the culture broth in contact with the polystyrene surfaces did not influence the biofilm structure. The increase in cell surface hydrophobicity (assessed by a test of microbial adhesion to solvents) after contact with SNI or SHY appeared to be associated with a strong capacity to form biofilms. Cultures exposed to biocides displayed a stable reduced susceptibility to a range of antibiotics (mainly aminoglycosides, cephalosporins, and quinolones) compared with cultures that were not exposed. SNI caused the greatest increase in resistances (14 antibiotics [48.3% of the total tested]) compared with TSP (1 antibiotic [3.4%]) and SHY (3 antibiotics [10.3%]). Adaptation to SHY involved changes in cell morphology (as observed by scanning electron microscopy) and ultrastructure (as observed by transmission electron microscopy) which allowed this bacterium to persist in the presence of severe SHY challenges. The findings of the present study suggest that the use of biocides at subinhibitory concentrations could represent a public health risk.

The antimalarial amodiaquine causes autophagic-lysosomal and proliferative blockade sensitizing human melanoma cells to starvation- and chemotherapy-induced cell death

Pharmacological inhibition of autophagic-lysosomal function has recently emerged as a promising strategy for chemotherapeutic intervention targeting cancer cells. Repurposing approved and abandoned non-oncological drugs is an alternative approach to the identification and development of anticancer therapeutics, and antimalarials that target autophagic-lysosomal functions have recently attracted considerable attention as candidates for oncological repurposing. Since cumulative research suggests that dependence on autophagy represents a specific vulnerability of malignant melanoma cells, we screened a focused compound library of antimalarials for antimelanoma activity. Here we report for the first time that amodiaquine (AQ), a clinical 4-aminoquinoline antimalarial with unexplored cancer-directed chemotherapeutic potential, causes autophagic-lysosomal and proliferative blockade in melanoma cells that surpasses that of its parent compound chloroquine. Monitoring an established set of protein markers (LAMP1, LC3-II, SQSTM1) and cell ultrastructural changes detected by electron microscopy, we observed that AQ treatment caused autophagic-lysosomal blockade in malignant A375 melanoma cells, a finding substantiated by detection of rapid inactivation of lysosomal cathepsins (CTSB, CTSL, CTSD). AQ-treatment was associated with early induction of energy crisis (ATP depletion) and sensitized melanoma cells to either starvation- or chemotherapeutic agent-induced cell death. AQ displayed potent antiproliferative effects, and gene expression array analysis revealed changes at the mRNA (CDKN1A, E2F1) and protein level (TP53, CDKN1A, CCND1, phospho-RB1 [Ser 780]/[Ser 807/811], E2F1) consistent with the observed proliferative blockade in S-phase. Taken together, our data suggest that the clinical antimalarial AQ is a promising candidate for repurposing efforts that aim at targeting autophagic-lysosomal function and proliferative control in malignant melanoma cells.

Establishment of Paclitaxel-resistant Breast Cancer Cell Line and Nude Mice Models, and Underlying Multidrug Resistance Mechanisms in Vitro and in Vivo

Breast cancer is a common malignant tumor which affects health of women and multidrug resistance (MDR) is one of the main factors leading to failure of chemotherapy. This study was conducted to establish paclitaxel-resistant breast cancer cell line and nude mice models to explore underlying mechanisms of MDR. The breast cancer drug-sensitive cell line MCF-7 (MCF-7/S) was exposed in stepwise escalating paclitaxel (TAX) to induce a resistant cell line MCF-7/TAX. Cell sensitivity to drugs and growth curves were measured by MTT assay. Changes of cell morphology and ultrastructure were examined by optical and electron microscopy. The cell cycle distribution was determined by flow cytometry. Furthermore, expression of proteins related to breast cancer occurrence and MDR was tested by immunocytochemistry. In Vivo, nude mice were injected with MCF-7/S and MCF-7/TAX cells and weights and tumor sizes were observed after paclitaxel treatment. In addition, proteins involved breast cancer and MDR were detected by immunohistochemistry. Compared to MCF-7/S, MCF-7/TAX cells had a higher resistance to paclitaxel, cross-resistance and prolonged doubling time. Moreover, MCF-7/TAX showed obvious alterations of ultrastructure. Estrogen receptor (ER) expression was low in drug resistant cells and tumors while expression of human epidermal growth factor receptor 2 (HER2) and Ki-67 was up-regulated. P-glycoprotein (P-gp), lung resistance-related protein (LRP) and glutathione-S-transferase-π (GST-π) involved in the MDR phenotype of resistant cells and tumors were all overexpressed. The underlying MDR mechanism of breast cancer may involve increased expression of P-gp, LRP and GST-π.

Effects of electroacupuncture of different intensities on energy metabolism of mitochondria of brain cells in rats with cerebral ischemia-reperfusion injury

To observe the effects of electroacupuncture (EA) of different intensities on lactate dehydrogernase (LDH), succinate dehydrogenase (SDH) and ATPase in brain tissue of rats with cerebral ischemia-reperfusion injury (CI/R). Forty male SD rats were uniformly randomized into sham operation group (group A), CI/R group (group B), CI/R+5 mA EA (group C), CI/R+3 mA EA (group D) and CI/R+1 mA EA (group E) groups with eight rats in each group. Transient general brain ischemia was induced by four-vessel occlusion and reperfusion. The rats in group C, group D and group E were punctured and stimulated at Baihui (GV20), Mingmen (GV4) and Zusanli (ST36) with the same intermittent and rarefaction-dense wave (30 to 50 Hz) and different electric current intensities: 5 mA, 3 mA and 1 mA for 20 min after CI/R. Then the activities of Na(+)-K(+)-ATPase, SDH and LDH in mitochondria of brain tissue were measured by spectrophotometry. The ischemic cerebral cortex tissue was taken for observing the ultrastructure changes of impaired nerve cells. Compared with group A, the activities of LDH, SDH and Na(+)-K(+)-ATPase were lowerer in the group B (P<0.05 or P<0.01). However, the activities of LDH, SDH and Na(+)-K(+)-ATPase were higher in the group D than those in the group B (P<0.05 orP<0.01). In group A, the anatomical structure of the cerebral cortex cells was basically normal; in group B, the neuronal cellular structures were severely damaged, the neuronal mitochondria got swelling, the mitochondrial cristae were broken, the medullated nerve fifibers were not integrated. In group C, group D and group E, the ultrastructure of impaired neuron were improved. Group D was the best among three groups above. EA of 3 mA intensity could strengthen aerobic metabolism by elevating the activities of SDH and LDH, meanwhile maintaining the ionic equilibrium in the exterior and interior brain cell and relieving the cellular edema by reinforcing the activities of Na(+)-K(+)-ATPase.

Amelioration of Paraquat-Induced Pulmonary Injury by Mesenchymal Stem Cells

Acute paraquat (PQ) poisoning induces redox cycle and leads to fatal injury of lung. Clinical management is supportive in nature due to lack of effective antidote, and the mortality is very high. Mesenchymal stem cells (MSCs) process the properties of immunomodulation, anti-inflammatory, and antifibrotic effects and oxidative stress resistance. MSC transplantation may theoretically serve as an antidote in PQ intoxication. In this study, we examined the potential therapeutic effects of MSCs in PQ-induced lung injury. The degree of PQ toxicity in the rat type II pneumocyte cell line, L2, and MSCs was evaluated by examining cell viability, ultrastructural changes, and gene expression. L2 cells treated with 0.5 mM PQ were cocultured in the absence or presence of MSCs. For the in vivo study, adult male SD rats were administered an intraperitoneal injection of PQ (24 mg/kg body weight) and were divided into three groups: group I, control; group II, cyclophosphamide and methylprednisolone; group III, MSC transplantation 6 h after PQ exposure. MSCs were relatively resistant to PQ toxicity. Coculture with MSCs significantly inhibited PQ accumulation in L2 cells and upregulated the expression of antioxidative heme oxygenase 1 and metallothionein 1a genes, reversed epithelial-to-mesenchymal transition, and increased the viability of PQ-exposed L2 cells. Treatment with MSCs resulted in a significant reduction in severity of liver and renal function deterioration, alleviated lung injury, and prolonged the life span of rats. Altogether, our results suggest that MSCs possess antidote-like effect through multifactorial protection mechanism. The results of this preclinical study demonstrate that transplantation of MSCs may be a promising therapy and should be further validated clinically.

Extremely low-frequency magnetic fields can impair spermatogenesis recovery after reversible testicular damage induced by heat

Male infertility is often related to reproductive age couples experiencing fertility-related issues. Men may have fertility problems associated with reversible testicular damage. Considering that men have been increasingly exposed to extremely low-frequency magnetic fields generated by the production, distribution and use of electricity, this study analyzed whether 60 Hz and 1 mT magnetic field exposure may impair spermatogenesis recovery after reversible testicular damage induced by heat shock using rats as an experimental model. Adult male rats were subjected to a single testicular heat shock (HS, 43 °C for 12 min) and then exposed to the magnetic field for 15, 30 and 60 d after HS. Magnetic field exposure during the spermatogenesis recovery induced changes in testis components volume, cell ultrastructure and histomorphometrical parameters. Control animals had a reestablished and active spermatogenesis at 60 d after heat shock, while animals exposed to magnetic field still showed extensive testicular degeneration. Magnetic field exposure did not change the plasma testosterone. In conclusion, extremely low-frequency magnetic field may be harmful to fertility recovery in males affected by reversible testicular damage.

The role of neuropeptide Y and aquaporin 4 in the pathogenesis of intestinal dysfunction caused by traumatic brain injury

BackgroundAlthough the exact incidence is unknown, traumatic brain injury (TBI) can lead to intestinal dysfunction. It has important influence on the early nutrition and prognosis of TBI patients. Experiments were designed to study the roles of neuropeptide Y (NPY) and aquaporin 4 (AQP4) in the pathogenesis of intestinal dysfunction caused by TBI and to find some new solutions for the treatment of intestinal dysfunction after TBI. MethodsForty adult male Wistar rats were randomly divided into control, mild trauma, moderate trauma, and severe trauma groups. TBI was induced by Feeney's impact method. Control animals were sham operated but not subjected to the impact test. All rats were killed 24 h after surgery. Blood samples were obtained from the abdominal aorta for enzyme-linked immunosorbent assay measurement of NPY concentrations. Jejunum segments 15 cm distal to the Treitz ligament were taken for analysis of NPY and AQP4 expression by polymerase chain reaction, Western blot, and immunohistochemistry. Pathologic changes in intestinal cell structure and ultrastructure were studied by light microscopy and transmission electron microscopy. ResultsThe specimens from different groups showed different degrees of structural changes, ranging from swelling and degeneration of villous epithelial cells to extensive denudation and collapse of the villi. The more severe the trauma, the more serious the degree of intestinal mucosal injury. Intestinal smooth muscle also showed varying degrees of edema and structural disorder. Electron microscopy showed that intestinal mitochondria had varying degrees of swelling and the structure of mitochondrial crista was disordered and even fractured. Plasma concentrations of NPY and jejunal gene and protein expressions of NPY and AQP4 increased significantly following TBI (P < 0.05), with greater increases at higher levels of injury. Moreover, there were positive correlations between NPY and AQP4 (P < 0.05). ConclusionsIncreasing grades of TBI caused increasing degrees of intestinal ischemia and edema, and thus caused increasingly severe intestinal dysfunction. AQP4 and NPY may be involved in the pathogenesis of intestinal dysfunction after TBI. Increased NPY levels may be responsible for intestinal ischemia and hypoxia, and AQP4 may play an important role in intestinal edema. Increased NPY levels may be one of the main causes for the increase in AQP4 after TBI.

UVA causes dual inactivation of cathepsin B and L underlying lysosomal dysfunction in human dermal fibroblasts

Cutaneous exposure to chronic solar UVA-radiation is a causative factor in photocarcinogenesis and photoaging. Recently, we have identified the thiol-dependent cysteine-protease cathepsin B as a novel UVA-target undergoing photo-oxidative inactivation upstream of autophagic-lysosomal dysfunction in fibroblasts. In this study, we examined UVA effects on a wider range of cathepsins and explored the occurrence of UVA-induced cathepsin inactivation in other cultured skin cell types. In dermal fibroblasts, chronic exposure to non-cytotoxic doses of UVA caused pronounced inactivation of the lysosomal cysteine-proteases cathepsin B and L, effects not observed in primary keratinocytes and occurring only to a minor extent in primary melanocytes. In order to determine if UVA-induced lysosomal impairment requires single or dual inactivation of cathepsin B and/or L, we used a genetic approach (siRNA) to selectively downregulate enzymatic activity of these target cathepsins. Monitoring an established set of protein markers (including LAMP1, LC3-II, and p62) and cell ultrastructural changes detected by electron microscopy, we observed that only dual genetic antagonism (targeting both CTSB and CTSL expression) could mimic UVA-induced autophagic-lysosomal alterations, whereas single knockdown (targeting CTSB or CTSL only) did not display ‘UVA-mimetic’ effects failing to reproduce the UVA-induced phenotype. Taken together, our data demonstrate that chronic UVA inhibits both cathepsin B and L enzymatic activity and that dual inactivation of both enzymes is a causative factor underlying UVA-induced impairment of lysosomal function in dermal fibroblasts.

Mitochondrial injury induced by nanosized titanium dioxide in A549 cells and rats

The nanosized titanium dioxide (nano-TiO2) is an important nanoscale compound applied in many different fields because of its superior performance. Here, an anatase nano-TiO2 showed cytotoxicity in a dosage-dependent manner, which was in accordance with changes of A549 cell ultrastructure, A549 cell viability and intracellular ATP level. The lungs of rats treated with single intratracheal instillation of nano-TiO2 were injured, which was demonstrated by changes of alveolar epithelial cell ultrastructure, lung tissue pathology and lung tissue MDA level. The results of this study indicated that nano-TiO2 should be related to the generation of intracellular reactive oxygen species (ROS), which injured mitochondria and prevented the synthesis of ATP. The cells were approaching to apoptosis eventually. In macroscopic view, the lungs inevitably suffered.

Changes in distribution and ultrastructure of Langerhans cells in condyloma acuminatum tissues, and analysis of the underlying mechanism

To determine the changes in distribution and function of Langerhans cells (LCs) in condyloma acuminatum (CA) tissues, as well as the possible underlying mechanism. The expression of CD1a and E-cadherin in 26 CA lesions and 10 normal prepuce tissues was determined using the streptavidin peroxidase method. The mRNA expression of CD1a and E-cadherin was determined using reverse transcriptase polymerase chain reaction. The ultrastructure of LCs was observed under a transmission electronic microscope (TEM). In the CA tissues, the number of CD1a-positive LCs was significantly decreased (10.66 ± 11.71) compared with the number in normal prepuce tissues ( p < 0.05). The LCs in the CA tissues had smaller cell bodies with fewer and shortened cytodendrites. The CD1a mRNA expression in the CA tissues significantly decreased compared with that in the normal tissues (0.4066 ± 0.2671 vs. 0.7444 ± 0.3667; p < 0.01). The average E-cadherin staining score in the CA tissues was significantly lower than that in the normal tissues (2.36 ± 1.41 vs. 7.67 ± 1.64; p < 0.01). The E-cadherin mRNA expression in the CA tissues was also significantly lower than that in the normal tissues (0.1737 ± 0.1083 vs. 0.3786 ± 0.1460; p < 0.01). A positive correlation was observed between the LC number and E-cadherin expression density ( r = 0.8381, p < 0.05), as well as between the mRNA expression of CD1a and E-cadherin ( r = 0.8381, p < 0.05). TEM observation revealed changes in the morphology and quantity of subcellular organelles (Birbeck granules) in the CA tissues. CA lesions are characterized by a decreased number of LCs and antigen presentation dysfunction. The decrease in the number of LCs may be correlated with reduced E-cadherin expression, which hinders intraepidermal LC retention.