Morphological and structural characteristics of the elytra reduce impact damage to ladybird beetles.

Beetle elytra act as natural protective covers and effectively shield their flexible abdomens and fragile hindwings from damage. The existing studies have attributed this contribution of the elytra to its honeycomb structures. In this combined experimental and theoretical study, we used the seven-spotted ladybird beetle to demonstrate that both biological morphology and the hollow structure of the dome-like elytra combined to reduce damage during falling. The falling ladybird beetles had a high probability (59.52%) of hitting the ground with the costal edge of the elytra. This strategy could assist with converting the translational energy into rotational kinetic energy, resulting in the reduction of the impulse during falling. In addition, the hollow structures on the elytra could further absorb the residual impact energy. In the future, this biological paradigm could be used as a basis for the development of falling/landing techniques for advanced robots.

De Novo Sequencing Provides Insights Into the Pathogenicity of Foodborne Vibrio parahaemolyticus.

Vibrio parahaemolyticus is a common pathogenic marine bacterium that causes gastrointestinal infections and other health complications, which could be life-threatening to immunocompromised patients. For the past two decades, the pathogenicity of environmental V. parahaemolyticus has increased greatly, and the genomic change behind this phenomenon still needs an in-depth exploration. To investigate the difference in pathogenicity at the genomic level, three strains with different hemolysin expression and biofilm formation capacity were screened out of 69 environmental V. parahaemolyticus strains. Subsequently, 16S rDNA analysis, de novo sequencing, pathogenicity test, and antibiotic resistance assays were performed. Comparative genome-scale interpretation showed that various functional region differences in pathogenicity of the selected V. parahaemolyticus strains were due to dissimilarities in the distribution of key genetic elements and in the secretory system compositions. Furthermore, the genomic analysis-based hypothesis of distinct pathogenic effects was verified by the survival rate of mouse models infected with different V. parahaemolyticus strains. Antibiotic resistance results also presented the multi-directional evolutionary potential in environmental V. parahaemolyticus, in agreement with the phylogenetic analysis results. Our study provides a theoretical basis for better understanding of the increasing pathogenicity of environmental V. parahaemolyticus at the genome level. Further, it has a key referential value for the exploration of pathogenicity and prevention of environmental V. parahaemolyticus in the future.

[Quorum sensing molecule N-3-oxodecanoyl-L-homoserine lactone (3-oxo-C10-HSL) inhibits lipopolysaccharide-induced inflammatory responses of RAW264.7 macrophages].

Objective To explore the regulatory effect of quorum sensing molecule N-3-oxodecanoyl-L-homoserine lactone (3-oxo-C10-HSL) on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 macrophages. Methods RAW264.7 macrophages were divided into experimental group, control group and blank group. The experimental group was treated with different concentrations of 3-oxo-C10-HSL and LPS; the control group was treated with DMSO and LPS; and the blank group was treated with DMSO and PBS. Cells and supernatants were collected after 12 hours of stimulation. The mRNA expression of interleukin-6 (IL-6), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) were detected by real-time quantitative PCR, and the protein levels of IL-6 and TNF-α in supernatant were detected by ELSIA. Further, 25 µmol/L 3-oxo-C10-HSL and 100 ng/mL LPS were used to stimulate the cells for 15, 30 and 60 minutes, and the phosphorylation of nuclear factor κBp65 (NF-κBp65) was detected by Western blot analysis. Results The 3-oxo-C10-HSL could decrease the mRNA levels of IL-6, IL-1ß, TNF-α, MCP-1 and the protein levels of IL-6 and TNF-α in LPS-treated RAW264.7 macrophages in a dose-dependent manner. In addition, 3-oxo-C10-HSL could inhibit the phosphorylation of NF-κBp65 induced by LPS. Conclusion 3-oxo-C10-HSL can alleviate LPS-induced inflammatory responses in RAW264.7 macrophages by inhibiting activation of NF-κB signaling pathway.

Vibrio vulnificus cytolysin induces inflammatory responses in RAW264.7 macrophages through calcium signaling and causes inflammation in vivo.

Vibrio vulnificus is a food-borne marine pathogen that causes both life-threatening primary septicemia and necrotizing wound infections which accompany severe inflammation. Cytolysin is a very powerful virulence factor of V. vulnificus and is one of the likely candidates in the pathogenesis of V. vulnificus infections. However, the pathogenetic roles of cytolysin in V. vulnificus-induced inflammation are not well understood. In this study, we used the recombinant protein Vibrio vulnificus cytolysin (VVC) to demonstrate that VVC can induce inflammatory responses in RAW264.7 macrophages. Low dose (<5 µg/ml) VVC had no impact on cell viability and induced pro-inflammatory cytokines production in RAW264.7 macrophages such as IL-6 and TNF-α. Moreover, VVC induced p65, p38, ERK1/2, and AKT phosphorylation in RAW264.7 macrophages. We further demonstrated that BAPTA-AM, a specific intracellular calcium chelator, inhibited VVC-induced inflammatory responses including pro-inflammatory cytokines production and inflammatory signaling activation in RAW264.7 macrophages. In addition, VVC primed rather than actived NLRP3 inflammasome in RAW264.7 macrophages. To determine whether VVC have a direct inflammatory effect on the host, we examined the effects of VVC injected into the skin of mice. VVC stimulated a significant induction of mRNAs for the pro-inflammatory cytokine IL-6 and inflammatory chemokines such as MCP-1 and IP-10. Histology data also showed that VVC caused inflammatory responses in the skin of mice. Collectively, our findings indicated that VVC induced inflammatory responses in RAW264.7 macrophages and in vivo and suggested the possibility of targeting VVC as a strategy for the clinical management of V. vulnificus-induced inflammatory responses.

Beclin1 inhibition enhances paclitaxel­mediated cytotoxicity in breast cancer in vitro and in vivo.

Beclin1, a key regulator of autophagy, has been demonstrated to be associated with cancer cell resistance to chemotherapy. Paclitaxel is a conventional chemotherapeutic drug used in the clinical treatment of breast cancer. However, the function and mechanism of Beclin1 in paclitaxel­mediated cytotoxicity in breast cancer are not well defined. The present study demonstrated that paclitaxel suppressed cell viability and Beclin1 expression levels in BT­474 breast cancer cells in a dose­ and time­dependent fashion. Compared with the control, the knockdown of Beclin1 significantly enhanced breast cancer cell death via the induction of caspase­dependent apoptosis following paclitaxel treatment in vitro (P<0.05). In a BT­474 xenograft model, paclitaxel achieved substantial inhibition of tumor growth in the Beclin1 knockdown group compared with the control group. Furthermore, analysis of the publicly available Gene Expression Omnibus datasets revealed a clinical correlation between Beclin1 levels and the response to paclitaxel therapy in patients with breast cancer. Collectively, the present results suggest that Beclin1 protects breast cancer cells from apoptotic death. Thus, the inhibition of Beclin1 may be a novel way to improve the effect of paclitaxel. Additionally, Beclin1 may function as a favorable prognostic biomarker for paclitaxel treatment in patients with breast cancer.

Genomic and biological characterization of the Vibrio alginolyticus-infecting "Podoviridae" bacteriophage, vB_ValP_IME271.

As an opportunist pathogen, Vibrio alginolyticus (V. alginolyticus), causes disease in marine animals. Bacterial contamination of seafood is not uncommon, and phage therapy is considered a safe way to decontaminate such foods to control the emergence of vibriosis. Here, we report on the isolation of a new, virulent phage called vB_ValP_IME271 (designated phage IME271), which infects V. alginolyticus and was isolated from seawater. Phage IME271 displayed good pH (7-9) and temperature tolerance (< 40 °C) and had a broad host range against Vibrio isolates, including 7 strains of V. alginolyticus and11 strains of V. parahaemolyticus. The IME271 genome was sequenced and annotated, the results of which showed that this phage is a Podoviridae family member with a genome length of 50,345 base pairs. The complete genome is double-stranded DNA with a G+C content of 41.4%. Encoded within the genome are 67 putative proteins, of which only 22 coding sequences have known functions, and no tRNAs are present. The BLASTn results for IME271 showed that it only shares similarity with the Vibrio phage VPp1 (sequence identity score of 96% over 87% of the genome) whose host is V. parahaemolyticus. Comparative analysis showed that IME271 and VPp1 share a similar genomic structure, and the structural proteins are highly similar (> 95% similarity score). In summary, our work identified a new lytic Podoviridae bacteriophage, which is infective to V. alginolyticus and V. parahaemolyticus. This bacteriophage could potentially be used to control V. alginolyticus and V. parahaemolyticus infections in marine animals.

BECN1-knockout impairs tumor growth, migration and invasion by suppressing the cell cycle and partially suppressing the epithelial-mesenchymal transition of human triple-negative breast cancer cells.

Beclin1 (BECN1), which directly interacts with B­cell lymphoma 2, serves an important role in autophagy and is involved in the tumorigenesis of various types of cancer. However, the definite role of BECN1 in breast cancer remains controversial. Bi-allelic knockout of Becn1 in a mouse model leads to an embryonic lethal phenotype, which hampers further investigation. To generate cell lines with knockout of BECN1, the CRISPR/Cas9 technique was used to disrupt BECN1 in human triple-negative breast cancer (TNBC) MDA­MB­231 cells. To the best of our knowledge, the present study was the first to successfully disrupt BECN1 in MDA­MB­231 cells and to screen three stable monoclonal BECN1­knockout cell lines, suggesting that BECN1­knockout is not lethal in TNBC cells. Functional analysis revealed that complete loss of BECN1 suppressed MDA­MB­231 proliferation and colony formation via inducing G0/G1 cell cycle arrest, not apoptosis, in vitro. On the other hand, BECN1­knockout inhibited the migratory and invasive ability of MDA­MB­231 cells by partially reversing signals of epithelial-mesenchymal transition. Finally, analysis of publicly available gene expression datasets revealed increased expression of BECN1 in TNBC samples. Taken together, the results of the present study identified BECN1 as an oncogene, providing a novel potential target for the treatment of TNBC.

"In-Group" Communication in Marine Vibrio: A Review of N-Acyl Homoserine Lactones-Driven Quorum Sensing.

N-Acyl Homoserine Lactones (N-AHLs) are an important group of small quorum-sensing molecules generated and released into the surroundings by Gram-negative bacteria. N-AHLs play a crucial role in various infection-related biological processes of marine Vibrio species, including survival, colonization, invasion, and pathogenesis. With the increasing problem of antibiotic abuse and subsequently the emergence of drug-resistant bacteria, studies on AHLs are therefore expected to bring potential new breakthroughs for the prevention and treatment of Vibrio infections. This article starts from AHLs generation in marine Vibrio, and then discusses the advantages, disadvantages, and trends in the future development of various detection methods for AHLs characterization. In addition to a detailed classification of the various marine Vibrio-derived AHL types that have been reported over the years, the regulatory mechanisms of AHLs and their roles in marine Vibrio biofilms, pathogenicity and interaction with host cells are also highlighted. Intervention measures for AHLs in different stages are systematically reviewed, and the prospects of their future development and application are examined.

Complete genome sequence of a novel, virulent Ahjdlikevirus bacteriophage that infects Enterococcus faecium.

A novel virulent bacteriophage named vB_EfaP_IME199 that specifically infects Enterococcus faecium was isolated and characterized. Its optimal multiplicity of infection was 0.01, and it had a 30 minute outbreak period. High-throughput sequencing revealed that the phage has a dsDNA genome of 18,838 bp with 22 open reading frames. The genome has very low homology to all other bacteriophage sequences in the GenBank database. Run-off sequencing experiments confirmed that vB_EfaP_IME199 has short inverted terminal repeats. Phylogenetic analysis indicated that vB_EfaP_IME199 can be taxonomically classified as a new member of the genus Ahjdlikevirus of family Podoviridae.

Detection of Diverse N-Acyl-Homoserine Lactones in Vibrio alginolyticus and Regulation of Biofilm Formation by N-(3-Oxodecanoyl) Homoserine Lactone In vitro.

Quorum sensing (QS) is a cell-to-cell communication system based on the exchange of small intercellular signal molecules, such as N-Acyl homoserine lactones (AHLs), which act as cell-density mediators of QS gene expression, and are highly variable both in types and amounts in most Gram-negative Proteobacteria. Understanding the regulation of AHLs may contribute to the elucidation of cell density-dependent phenomena, such as biofilm formation. Vibrio alginolyticus is among the most frequently observed marine opportunistic Vibrio pathogens. However, AHL production of this species and its effects on biofilm formation remain to be understood. Here, our study reported the diverse AHL profiles of 47 marine-isolated V. alginolyticus strains and the effects of exogenous 3-oxo-C10-HSL on biofilm formation under different temperature conditions (16°C and 28°C). A total of 11 detected AHLs were produced by the isolates, of which 3-OH-C4-HSL, 3-oxo-C10-HSL and 3-oxo-C14-HSL comprised the largest proportions. We also observed that moderate levels of exogenous 3-oxo-C10-HSL (10 and 20 µM) could induce or enhance biofilm formation and alter its structure, while high levels (40 and 100 µM) did not significantly improve and even inhibited biofilm formation in V. alginolyticus. Further, regulation by exogenous 3-oxo-C10-HSL was both concentration- and temperature-dependent in V. alginolyticus.

CD147 knockdown improves the antitumor efficacy of trastuzumab in HER2-positive breast cancer cells.

Trastuzumab is widely used in the clinical treatment of human epidermal growth factor receptor-2 (HER2)-positive breast cancer, but the patient response rate is low. CD147 stimulates cancer cell proliferation, migration, metastasis and differentiation and is involved in chemoresistance in many types of cancer cells. Whether CD147 alters the effect of trastuzumab on HER2-positive breast cancer cells has not been previously reported. Our study confirmed that CD147 suppression enhances the effects of trastuzumab both in vitro and in vivo. CD147 suppression increased the inhibitory rate of trastuzumab and cell apoptosis in SKBR3, BT474, HCC1954 and MDA-MB453 cells compared with the controls. Furthermore, CD147 knockdown increased expression of cleaved Caspase-3/9 and poly (ADP-ribose) polymerase (PARP) and decreased both mitogen-activated protein kinase (MAPK) and Akt phosphorylation in the four cell lines. In an HCC1954 xenograft model, trastuzumab achieved greater suppression of tumor growth in the CD147-knockdown group than in the shRNA negative control (NC) group. These data indicated that enhancement of the effect of trastuzumab on HER2-positive cells following CD147 knockdown might be attributed to increased apoptosis and decreased phosphorylation of signaling proteins. CD147 may be a key protein for enhancing the clinical efficacy of trastuzumab.

An Innovative Method for Rapid Identification and Detection of Vibrio alginolyticus in Different Infection Models.

Vibrio alginolyticus is one of the most common pathogenic marine Vibrio species, and has been found to cause serious seafood-poisoning or fatal extra-intestinal infections in humans, such as necrotizing soft-tissue infections, bacteremia, septic shock, and multiple organ failures. Delayed accurate diagnosis and treatment of most Vibrio infections usually result to high mortality rates. The objective of this study was to establish a rapid diagnostic method to detect and identify the presence of V. alginolyticus in different samples, so as to facilitate timely treatment. The widely employed conventional methods for detection of V. alginolyticus include biochemical identification and a variety of PCR methods. The former is of low specificity and time-consuming (2-3 days), while the latter has improved accuracy and processing time. Despite such advancements, these methods are still complicated, time-consuming, expensive, require expertise and advanced laboratory systems, and are not optimal for field use. With the goal of providing a simple and efficient way to detect V. alginolyticus, we established a rapid diagnostic method based on loop-mediated Isothermal amplification (LAMP) technology that is feasible to use in both experimental and field environments. Three primer pairs targeting the toxR gene of V. alginolyticus were designed, and amplification was carried out in an ESE tube scanner and Real-Time PCR device. We successfully identified 93 V. alginolyticus strains from a total of 105 different bacterial isolates and confirmed their identity by 16s rDNA sequencing. We also applied this method on infected mouse blood and contaminated scallop samples, and accurate results were both easily and rapidly (20-60 min) obtained. Therefore, the RT-LAMP assay we developed can be conveniently used to detect the presence of V. alginolyticus in different samples. Furthermore, this method will also fulfill the gap for real-time screening of V. alginolyticus infections especially while on field.

Characterization and Genomic Analysis of Quinolone-Resistant Delftia sp. 670 Isolated from a Patient Who Died from Severe Pneumonia.

Antibiotic-resistant opportunistic pathogens have become a serious concern in recent decades, as they are increasingly responsible for hospital-acquired infections. Here, we describe quinolone-resistant Delftia sp. strain 670, isolated from the sputum of a patient who died from severe pulmonary infection. The draft genome sequence of this strain was obtained by whole-genome shotgun sequencing, and was subjected to comparative genome analysis. Genome analysis revealed that one critical mutation (Ser83Ile in gyrA) might play a decisive role in quinolone resistance. The genome of Delftia sp. strain 670 contains both type II and type VI secretion systems, which were predicted to contribute to the virulence of the strain. Phylogenetic analysis, assimilation tests, and comparative genome analysis indicated that strain 670 differed from the four known Delftia species, suggesting this strain could represent a novel species. Although the study could not determine the strain 670 as the pathogen led to mortality, our findings also presented the pathogenic potential of Delftia species, and the increasing severity of antibiotic resistance among emerging opportunistic pathogens. The whole genome sequencing and comparative analysis improved our understanding of genome evolution in the genus Delftia, and provides the foundation for further study on drug resistance and virulence of Delftia strains.

Detection of Extended-Spectrum ß-Lactamase and Plasmid-Mediated Quinolone Resistance Determinants in Escherichia coli Isolates from Retail Meat in China.

The aim of this study was to investigate the presence of extended-spectrum ß-lactamase (ESBL) and plasmid-mediated quinolone resistance (PMQR) genes in Escherichia coli isolated from retail meat samples in Henan Province, China. E. coli isolates were detected in 179 of 645 (27.7%) retail meat samples. Resistance of these isolates to antimicrobials was commonly observed, with 78.2% of isolates resistant to streptomycin, 74.3% resistant to tetracycline and 54.2% resistant to trimethoprim/sulfamethoxazole. Of the 179 isolates, 30 (16.7%) expressed ESBL, with blaTEM-1 (n = 17) and bla(CTX-M-14) (n = 9) most commonly mediating the ESBL phenotype. PMQR genes were present in 14 isolates (7.8%), with qnr and aac(6')-Ib-cr detected alone or in combination in nine (5.0%) and seven isolates (3.9%), respectively. The qnr genes detected included qnrS1 (n = 5), qnrA1 (n = 3), and qnrB4 (n = 1). The qepA gene was absent among these isolates. CTX-M-14 was the most prevalent ESBL type among the PMQR-positive isolates. The qnr and aac(6')-Ib-cr genes were found to co-reside and be co-transferred with blaCTX-M-14 or blaTEM-1 in five isolates. Our data suggest that retail meat may act as a reservoir for multi-resistant E. coli and may facilitate the dissemination of resistance genes.

The protective role of interleukin-11 against neutron radiation injury in mouse intestines via MEK/ERK and PI3K/Akt dependent pathways.

BACKGROUND: Neutron irradiation (IR) has been proven to cause more serious damage than gamma IR. Preventing and curing neutron IR damage remains an urgent issue. AIMS: The objective of this study was to investigate the radioprotective effects of IL-11 against neutron IR-induced damage in small intestine of mice. METHODS: Mice were exposed to 3-Gy neutron IR whole body and then treated with 500 µg/kg interleukin-11 (IL-11) intraperitoneally every day. Mice were observed at various time-points over 1-5 days after IR. IEC-6 cells were exposed to 4 Gy neutron IR, and 100 ng/mL rhIL-11 was added to culture medium. Cell proliferation activity was estimated by MTT assay and rates of apoptosis were estimated by flow cytometry. RESULTS: IL-11 slightly alleviated the incidence of diarrhea in the mice and promoted intestinal epithelia regeneration. In the in vitro study, neutron IR activated extracellular signal-regulated kinase (ERK)1/2 phosphorylation in intestinal epithelial cells constitutively, which was initially suppressed and then activated later by IL-11. The MEK-specific inhibitor U0126 could antagonize the positive effect of IL-11 on cell growth. Phosphatidylinositol 3-kinase (PI3K)/Akt pathway activation was suppressed after neutron IR, but could be triggered by IL-11 to protect the cells. The PI3K inhibitor LY294002 suppressed the positive effect of IL-11 on cell growth, and antagonized the protective effect of IL-11 against cell death after neutron IR. CONCLUSION: IL-11 increases cell proliferation after neutron IR in MEK and PI3K-dependent signaling pathways, but protects cells against death only in the PI3K-dependent signaling pathway.

[Preparation and characterization of monoclonal antibody against Vibrio vulnificus].

AIM: To prepare high-performance and specific monoclonal antibody (mAb) against Vibrio vulnificus and carry out characterization. METHODS: BALB/c mice were immunized with Vibrio vulnificus protein, and hybridoma cells against Vibrio vulnificus were produced by cellsion technique. The titers of mAbs against vvhA and cross-reaction between the anti-vvhA mAb and other other important marine bacteria were screened by ELISA and Western blot. RESULTS: Five strains of hybridoma were obtained. Identification result indicated that 5 mAbs have favourable specifity and immunoreactivity. CONCLUSION: Specific mAbs against Vibrio vulnificus were produced which provides an important preparation for establishing rapid-detection kit of detecting Vibrio vulnificus.

[Jak/STAT signaling pathway of IL-11 in the protection of intestinal epithelial cells from neutron radiation].

AIM: To explore the effect of IL-11 on the activation of Jak/STAT pathway and the expressions of Bax and Bcl-2 in the intestinal epithelial cells exposed to neutron radiation. METHODS: The BALB/c mice and IEC-6, irradiated by 4 Gy neutron with or without IL-11 treatment, served as in vivo and in vitro model seperately. The changes of the intestines, activity of Jak1 and STAT3 and expressions of Bax and Bcl-2 were observed by HE staining, Western blot, EMSA, immunohistochemistry and image analysis. RESULTS: (1)Mice exposed to neutron radiation showed severe intestinal damages and no obvious regeneration was seen. IL-11-treated mice had a larger number of cryptal epithelial cells and crypts. (2)Neutron radiation decreased the activities of Jak1 and STAT3, while IL-11 increased their activities. (3) Neutron radiation decreased the expression of Bax and didn't change the level of Bcl-2 in the murine intestine. IL-11 administration decreased the expression of Bax and increased that of Bcl-2. CONCLUSION: The mechanism of the intestinal protection of IL-11 in neutron irradiation might be that IL-11 stimulation triggered activation of Jak/STAT pathway, downregulated the expression of Bax and upregulated the expression of Bcl-2.

[Effect of IL-2 on the growth and apoptosis of intestinal epithelial cells radiated by neutron and mechanisms of IL-2 on the injured IEC-6].

AIM: To observe the effect of neutron radiation on intestinal epithelial cells 6 (IEC-6), to study the effect of IL-2 on the proliferation and recovery of neutron-injured IEC-6, and to investigate the regulatory mechanisms of IL-2 on the injured IEC-6. METHODS: 4Gy-neutron-injured IEC-6 were treated by IL-2, with or without the blocking agent JAK(1) (A77-1726). The change of proliferative activity and death manner of the treated IEC-6 were detected by MTT colorimetry and flow cytometry at 10, 15, 30 minutes and 1, 3, 6, 12, 24, 48, 72 hours respectively. The expression of IL-2Rbeta and the activation of JAK(1) of neutron-injured IEC-6 treated by IL-2 were detected by immunocytochemical stainning and Western blot. RESULTS: After IEC-6 were radiated by 4 Gy neutron for 24 hours, the proliferative activity of IEC-6 decreased markedly but increased strikingly after IL-2 treatment (P<0.05). The apoptosis of IEC-6 in IL-2-treated group decreased (P<0.05), but there was no obvious difference in necrotic cell number. After neutron-injured IEC-6 were treated by IL-2, JAK(1) was activated at 10 and 15 minutes, and the expression of IL-2Rbeta increased apparently at 24 hours. When treated by JAK(1) and IL-2, the proliferative activity of neutron-injured IEC-6 was much lower than that in IL-2-treated group. CONCLUSION: IL-2 can accelerate the proliferation of neutron-radiated IEC-6 and protect them from neutron injury. IL-2Rbeta and JAK(1) participate in the regulation of neutron-injured IEC-6 by IL-2.

Effect of recombinant human interleukin-11 on expressions of interleukin-11 receptor alpha-chain and glycoprotein 130 in intestinal epithelium cell line-6 after neutron irradiation.

AIM: To explore the effect of recombinant human interleukin-11 (rhIL-11) on the expressions of interleukin-11 receptor alpha-chain (IL-11Ralpha) and an additional signal transducer glycoprotein 130 (gp130) in intestinal epithelium cell line-6 (IEC-6) after neutron irradiation. METHODS: Cultured IEC-6 cells were exposed to 4.0Gy neutron and treated with 100 ng/mL rhIL-11 12 h prior to or immediately after irradiation. The apoptosis and necrosis rates and expressions of IL-11Ralpha and gp130 were observed by flow cytometry, immunohistochemistry, Western blot and image analysis. RESULTS: The apoptosis rate of IEC-6 cells was increased by irradiation at 6 h (P < 0.01), IL-11 stimulation resulted in a decreased apoptosis rate in irradiated IEC-6 cells (P < 0.05). In normal control IEC-6 cells, intense immunoreactivity of IL-11Ralpha was located within the cell membrane and cytoplasm. The level of IL-11Ralpha expression significantly decreased at 6 h after irradiation (P < 0.01) and restored at 24 h after irradiation. In IEC-6 cells treated with both radiation and rhIL-11, the level of IL-11Ralpha expression was higher than that of irradiated cells (P < 0.05). When it came to gp130 protein, it was located in the cytoplasm of IEC-6 cells. After irradiation, we found a progressive decrease in the expression of gp130 protein (P < 0.05) in 48 h post-radiation, while in rhIL-11-stimulated cells, it came back to normal level at 24 h after irradiation and decreased at 48 h, but was still higher than that of only irradiated cells (P < 0.05). CONCLUSION: rhIL-11 can protect IEC-6 cells from neutron irradiation. The protective effect of rhIL-11 might be connected with its ability to up-regulate the expressions of specific ligand-binding subunit IL-11Ralpha and signal-transducing subunit gp130.

[The expression of TNF-alpha in the intestine of mice irradiated by neutron and gamma rays].

AIM: To study the expression of tumor necrosis factor alpha (TNF-alpha) in the intestine of mice irradiated by neutron and gamma rays. METHODS: 350 male BALB/c mice were irradiated with neutron and gamma rays of different doses, and sacrificed at 6 and 12 hours, 1, 2, 3, 4, 5, 7, 10, 14, 21 and 28 days after irradiation. The TNF-alpha in the mice intestinal tissue was detected by means of immunohistochemical staining and image analysis. RESULTS: In normal control mice, TNF-alpha was expressed in the cytoplasm of macrophages in intestinal villus interstitium, submucosa and lymph tissue. After 2.5Gy neutron radiation, TNF-alpha was decreased progressively within 2 days, increased obviously in macrophages and crypt cells during the 3rd-7th day, reached the peak at the 5th day and recovered to normal level at the 14th day. TNF-alpha was decreased progressively within 4 days after 4.0 and 5.5Gy neutron and 12Gy gamma ray irradiation. TNF-gamma was increased obviously in 6-12 hours, decreased on the first day, increased at the 2nd-5th day, peaked at the third day and recovered at the 10th day after 5.5Gy gamma ray irradiation. CONCLUSION: Neutron and gamma ray radiation induce different expression profile of endogenous TNF-gamma in small intestine, which may be related with the pathologic courses of irradiation-induced damage and repair of intestine.