PDK inhibition promotes glucose utilization, reduces hepatic lipid deposition, and improves oxidative stress in largemouth bass (Micropterus salmoides) by increasing pyruvate oxidative phosphorylation.

In omnivorous fish, the pyruvate dehydrogenase kinases (PDKs)-pyruvate dehydrogenase E1α subunit (PDHE1α) axis is essential in the regulation of carbohydrate oxidative catabolism. Among the existing research, the role of the PDKs-PDHE1α axis in carnivorous fish with poor glucose utilization is unclear. In the present study, we determined the effects of PDK inhibition on the liver glycolipid metabolism of largemouth bass (Micropterus salmoides). DCA is a PDK-specific inhibitor that inhibits PDK by binding the allosteric sites. A total of 160 juvenile largemouth bass were randomly divided into two groups, with four replicates of 20 fish each, fed a control diet and a control diet supplemented with dichloroacetate (DCA) for 8 weeks. The present results showed that DCA supplementation significantly decreased the hepatosomatic index, triglycerides in liver and serum, and total liver lipids of largemouth bass compared with the control group. In addition, compared with the control group, DCA treatment significantly down-regulated gene expression associated with lipogenesis. Furthermore, DCA supplementation significantly decreased the mRNA expression of pdk3a and increased PDHE1α activity. In addition, DCA supplementation improved glucose oxidative catabolism and pyruvate oxidative phosphorylation (OXPHOS) in the liver, as evidenced by low pyruvate content in the liver and up-regulated expressions of glycolysis-related and TCA cycle/OXPHOS-related genes. Moreover, DCA consumption decreased hepatic malondialdehyde (MDA) content, enhanced the activities of superoxide dismutase (SOD), and increased transforming growth factor beta (tgf-ß), glutathione S-transferase (gst), and superoxide dismutase 1 (sod1) gene expression compared with the control diet. This study demonstrated that inhibition of PDKs by DCA promoted glucose utilization, reduced hepatic lipid deposition, and improved oxidative stress in largemouth bass by increasing pyruvate OXPHOS. Our findings contribute to the understanding of the underlying mechanism of the PDKs-PDHE1α axis in glucose metabolism and improve the utilization of dietary carbohydrates in farmed carnivorous fish.

Mildronate triggers growth suppression and lipid accumulation in largemouth bass (Micropterus salmoides) through disturbing lipid metabolism.

Many metabolic diseases in fish are often associated with lowered mitochondrial fatty acid ß-oxidation (FAO). However, the physiological role of mitochondrial FAO in lipid metabolism has not been verified in many carnivorous fish species, for example in largemouth bass (Micropterus salmonids). In the present study, a specific mitochondrial FAO inhibitor, mildronate (MD), was used to investigate the effects of impaired mitochondrial FAO on growth performance, health status, and lipid metabolism of largemouth bass. The results showed that the dietary MD treatment significantly suppressed growth performance and caused heavy lipid accumulation, especially neutral lipid, in the liver. The MD-treated fish exhibited lower monounsaturated fatty acid and higher long-chain polyunsaturated fatty acids in the muscle. The MD treatment downregulated the gene expressions in lipolysis and lipogenesis, as well as the expressions of the genes and some key proteins in FAO without enhancing peroxisomal FAO. Additionally, the MD-treated fish had lower serum aspartate aminotransferase activity and lower pro-inflammation- and apoptosis-related genes in the liver. Taken together, MD treatment markedly induced lipid accumulation via depressing lipid catabolism. Our findings reveal the pivotal roles of mitochondrial FAO in maintaining health and lipid homeostasis in largemouth bass and could be hopeful in understanding metabolic diseases in farmed carnivorous fish.

A novel morphometry system automatically assessing the growth and regeneration of intestinal organoids.

As compared with 2D cell line cultures, 3D intestinal organoids are better at maximally recapitulating the physiological features of stem cells in vivo. However, the complex 3D structure is an obstacle which must be objectively and automatically evaluated to assess colony growth and regeneration. Meanwhile, no internal standard currently exists for evaluating the size of heterogeneities in organoids or defining those regenerating colonies. Herein, we developed a simple morphometry system to image MTT-stained organoids. The growth curve of organoids can be automatically generated based upon analyzing the integrated optical density using software. Referencing the definition standards of in vivo regenerating crypts, the perimeters of crypts cultured 24 h after seeding were selected as an "Organoid Unit" to further evaluate colony survival rate and colony size heterogeneities after exposure to varying doses of irradiation. Moreover, the morphometry-based quantification data collected confirmed other findings associated with radiation sensitizing effects of ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3-related protein (ATR) inhibitor and the radiation protective effect of IL-22. In summary, the novel organoid morphometry system combined with a new internal reference is a practical means for standardizing assessment of growth, survival and regeneration of intestinal organoid colonies. This method has promise to facilitate drug screens in intestinal and other organoid systems.

Metallothionein deficiency aggravates depleted uranium-induced nephrotoxicity.

Depleted uranium (DU) has been widely used in both civilian and military activities, and the kidney is the main target organ of DU during acute high-dose exposures. In this study, the nephrotoxicity caused by DU in metallothionein-1/2-null mice (MT-/-) and corresponding wild-type (MT+/+) mice was investigated to determine any associations with MT. Each MT-/- or MT+/+ mouse was pretreated with a single dose of DU (10mg/kg, intraperitoneal injection) or an equivalent volume of saline. After 4days of DU administration, kidney changes were assessed. After DU exposure, serum creatinine and serum urea nitrogen in MT-/- mice significantly increased than in MT+/+ mice, with more severe kidney pathological damage. Moreover, catalase and superoxide dismutase (SOD) decreased, and generation of reactive oxygen species and malondialdehyde increased in MT-/- mice. The apoptosis rate in MT-/- mice significantly increased, with a significant increase in both Bax and caspase 3 and a decrease in Bcl-2. Furthermore, sodium-glucose cotransporter (SGLT) and sodium-phosphate cotransporter (NaPi-II) were significantly reduced after DU exposure, and the change of SGLT was more evident in MT-/- mice. Finally, exogenous MT was used to evaluate the correlation between kidney changes induced by DU and MT doses in MT-/- mice. The results showed that, the pathological damage and cell apoptosis decreased, and SOD and SGLT levels increased with increasing dose of MT. In conclusion, MT deficiency aggravated DU-induced nephrotoxicity, and the molecular mechanisms appeared to be related to the increased oxidative stress and apoptosis, and decreased SGLT expression.

Micro-nano aeration is a promising alternative for achieving high-rate partial nitrification.

Biological nitrogen removal is the most prevalent wastewater nitrogen removal process but nitrification limits the rate of the whole process mainly due to the low efficiency of oxygen transfer. In this study, clean-water oxygenation tests, batch tests, long-term operational tests and metagenomic analyses were applied to assess the effects of micro-nano aeration on nitrification. The oxygen transfer coefficient (KLa), oxygen transfer rate (OTR) and oxygen transfer efficiency (OTE) were determined to be 0.56 min-1, 0.36 kg·m-3·h-1 and 71.43%, respectively during micro-nano-bubble aeration. Impressively, these values were 15 times greater than those of conventional aeration. The results of batch tests and long-term operation experiments found that the ammonia removal rate of micro-nano aeration was 3.2-fold that of conventional aeration. The energy cost for micro-nano aeration was calculated to be 3694.5 mg NH4+-N/kW·h, a 50% energy saving in comparison to conventional aeration. In addition, the nitrite accumulation ratio in the Micro-nano (MN) reactor was 1.5 that of the Conventional (CV) reactor. Metagenomic analysis showed that after long-term operation in micro-nano aeration, the abundances of genes encoding ammonia monooxygenase (amoA) and hydroxylamine oxidoreductase (hao) was more than 8-fold and 4-fold of those in conventional aeration, respectively. The abundance of the gene encoding nitrite oxidoreductase (nxrA) was similar in both reactors. Read taxonomy revealed that abundance of AOB-Nitrosomonas increased significantly when using micro-nano aeration, while abundance of NOB-Nitrospira abundance was similar in both reactors. The results of this study indicated that the micro-nano aeration process will increase the ammonia oxidation performance by enhancing oxygen transfer but was also shown to be beneficial for enhancing partial nitrification by specific enrichment of ammonia oxidizing bacteria. This latter result demonstrates the potential benefits of the micro-nano aeration process as an alternative approach to establishing high-rate partial nitrification.

Methods and Influencing Factors for the Simple and Rapid Identification of Depleted Uranium Weapon Use under Battlefield Conditions.

The purpose of this paper is to explore how to rapidly and easily identify depleted uranium (DU) samples under battlefield conditions and to study the factors that influence their measurement. The air-absorbed dose rate and surface contamination levels for DU samples of 2-330 g were measured using a patrol instrument and portable energy spectrometer. The results were analyzed in accordance with IAEA standards for judging radioactive substances. The energy spectra of 5-g quantities of DU samples were analyzed using a high-purity germanium gamma spectrometer, and the uranium content of 100 mg DU samples was determined with an inductively coupled plasma mass spectrometer to clarify the type and composition of the uranium. The same batches of DU samples were identified using a portable gamma-ray spectrometer. We added 0-5 g environmental soil powders at different proportions. After sealing, the spectra were collected with a detection distance of 1-5 cm for 10 min. The activities of U and U nuclides in the samples were detected with an NaI(TI) scintillation detector. The U and U mass abundances in samples were calculated from measured specific activities. The sample was determined to contain DU if the U to U ratio was below 0.00723. It is found that for detecting DU materials with a low activity, surface contamination level measurements are more effective than calculating the air-absorbed external irradiation dose rate. Hence, for low-activity samples suspected to be radioactive, a radiometer with a high sensitivity for surface contamination is recommended, and the optimal measurement distance is 1-3 cm. Under all detection conditions, U can be identified using a portable gamma spectrometer, whereas U can only be detected under certain conditions. If these nuclides can be detected simultaneously, a U to U ratio of below 0.00723 indicates the presence of DU. The main factors affecting this identification include the sample mass, sample purity, measurement distance, and measurement time. For the rapid identification of DU with a portable gamma-ray spectrometer, the mass of uranium in the sample must be more than 1 g, the measuring distance needs to be less than 1 cm, and the measuring time must be 1-10 min. It is feasible to use a portable gamma-ray spectrometer to rapidly identify the types and composition of nuclides in DU samples. The detection of U activity is a precondition for the identification of DU.

A Proresolving Peptide Nanotherapy for Site-Specific Treatment of Inflammatory Bowel Disease by Regulating Proinflammatory Microenvironment and Gut Microbiota.

The incidence and prevalence of inflammatory bowel disease (IBD) increases steadily worldwide. There is an urgent need for effective and safe IBD therapies. Accelerated resolution of inflammation is a new strategy for the management of inflammatory diseases. For effective and safe IBD treatment, herein a smart nanotherapy (i.e. oxidation-responsive nanoparticles containing a proresolving annexin A1-mimetic peptide Ac2-26, defined as AON) is developed, which can release packaged Ac2-26, in response to highly expressed reactive oxygen species (ROS) at diseased sites. AON effectively protects Ac2-26 from degradation in the enzyme-rich environment of the gastrointestinal tract. By delivering this nanotherapy to the inflamed colons of mice with IBD, site-specific release and accumulation of Ac2-26 in response to high levels of ROS at the inflammatory sites are achieved. Mechanistically, the Ac2-26-containing, oxidation-labile nanotherapy AON effectively decreases the expression of proinflammatory mediators, attenuates trafficking and infiltration of inflammatory cells, promotes efferocytosis of apoptotic neutrophils, and increases phenotypic switching of macrophages. Therapeutically, AON reduces symptoms of inflammation, accelerates intestinal mucosal wound healing, reshapes the gut microbiota composition, and increases short-chain fatty acid production. Additionally, oral delivery of this nanomedicine shows excellent safety profile in a mouse model, conferring the confidence for further development of a targeted precision therapy for IBD and other inflammatory diseases.

Identification of G2/M phase transition by sequential nuclear and cytoplasmic changes and molecular markers in mice intestinal epithelial cells.

Although the regulatory network of G2/M phase transition has been intensively studied in mammalian cell lines, the identification of morphological and molecular markers to identify G2/M phase transition in vivo remains elusive. In this study, we found no obvious morphological changes between the S phase and G2 phase in mice intestinal epithelial cells. The G2 phase could be identified by Brdu incorporation resistance, marginal and scattered foci of histone H3 phosphorylated at Ser10 (pHH3), and relatively intact Golgi ribbon. Prophase starts with nuclear transformation in situ, which was identified by a series of prophase markers including nuclear translocation of cyclinB1, fragmentation of the Golgi complex, and a significant increase in pHH3. The nucleus started to move upwards in the late prophase and finally rounded up at the apical surface. Then, metaphase was initiated as the level of pHH3 peaked. During anaphase and telophase, pHH3 sharply decreased, while Ki67 was obviously bound to chromosomes, and PCNA was distributed throughout the whole cell. Based on the aforementioned markers and Brdu pulse labeling, it was estimated to take about one hour for most crypt cells to go through the G2 phase and about two hours to go through the G2-M phase. It took much longer for crypt base columnar (CBC) stem cells to undergo G2-prophase than rapid transit amplifying cells. In summary, a series of sequentially presenting markers could be used to indicate the progress of G2/M events in intestinal epithelial cells and other epithelial systems in vivo.

Effect of a novel polyethylene glycol compound on lung lavage in dogs after the inhalation of depleted uranium dust.

PURPOSE: The purpose of this study was to assess the effect of a lavage solution containing methoxypolyethylene glycol 4-(3,4-dihydroxyphenethylamino)-4-oxobutanoate (MDO) for whole lung lavage (WLL) in dogs after the inhalation of depleted uranium (DU) dust at a dose of 30 mgUkg-1. MATERIALS AND METHODS: WLL was performed using lavage solutions made of normal saline (saline group) or normal saline plus MDO (MDO group) at 2 days post-DU exposure. Meanwhile, a control group was set up without any treatment. RESULTS: At 10 days post-DU exposure, the saline and MDO groups had a lower DU content in urine and lung compared with the DU group (without lavage), while the MDO group content was significantly lower than that in the saline group. In terms of blood urea nitrogen and creatinine levels, the DU group maintained relatively high levels from day 3 to day 10; the saline group levels were reduced compared with the DU group at day 8 and day 10, while the MDO group levels remained markedly lower than both the DU and saline group levels. Pathological changes in the lungs and kidneys showed that the saline group was improved compared with the DU group, but not as significantly as the MDO group. CONCLUSIONS: In brief, WLL has a remarkable effect in promoting the decorporation of inhaled DU dust in the lungs of dogs. By comparison, a MDO-containing lavage solution has a better lavage effect than normal saline.

Zinc protects human kidney cells from depleted uranium-induced apoptosis.

Depleted uranium (DU) is a weak radioactive heavy metal, and zinc (Zn) is an effective antidote to heavy metal poisoning. However, the effect of Zn on DU-induced cytotoxicity and apoptosis is not completely understood. The purpose of this study was to evaluate the effect of Zn on DU-induced cell apoptosis in human kidney cells (HK-2) and explore its molecular mechanism. Pre-treatment with Zn significantly inhibited DU-induced apoptosis. It reduced the formation of reactive oxygen species in the cells, increased the catalase (CAT) and glutathione (GSH) concentrations, suppressed the DU-induced soluble Fas receptor (sFasR) and soluble Fas ligand (sFasL) overexpression, suppressed the release of cytochrome c and apoptosis inhibitor factor (AIF) from mitochondria to cytoplasm, inhibited the activation of caspase-9, caspase-8 and caspase-3, and induced metallothionein (MT) expression. Furthermore, exogenous MT effectively inhibited DU-induced cell apoptosis. In conclusion, mitochondrial and FasR-mediated apoptosis pathways contribute to DU-induced apoptosis in HK-2 cells. Through independent mechanisms, such as indirect antioxidant effects, inhibition of the activation of caspase-9, caspase-8 and caspase-3, and induction of MT expression, Zn inhibits DU-induced apoptosis.

Immunological changes of chronic oral exposure to depleted uranium in mice.

Direct ingestion of contaminated soil by depleted uranium (DU) might lead to internal exposure to DU by local populations through hand contamination. The purpose of this study was to assess the immunological changes of long-term exposure to various doses of DU in mice. Three-week-old Kunming mice were divided into the following 4 groups based on the various feeding doses (containing DU): 0 (control group), 3 (DU3 group), 30 (DU30 group), and 300 mg/kg feed (DU300 group). After 4 months of exposure, in the DU300 group, the innate immune function decreased, manifesting as decreased secretion of nitric oxide, interleukin (IL)-1ß, IL-18, and tumour necrosis factor (TNF)-α in the peritoneal macrophages, as well as reduced cytotoxicity of the splenic natural killer cells. Moreover, the cellular and humoral immune functions were abnormal, as manifested by decreased proliferation of the splenic T cells, proportion of the cluster of differentiation (CD) 3(+) cells, ratio of CD4(+)/CD8(+) cells and delayed-type hypersensitivity, and increased proliferation of the splenic B cells, total serum immunoglobin (Ig) G and IgE, and proportion of splenic mIgM(+)mIgD(+) cells. Through stimulation, the secretion levels of interferon (IFN)-γ and TNF-α in the splenic cells were reduced, and the levels of IL-4 and IL-10 were increased. By comparison, in the DU30 and DU3 groups, the effects were either minor or indiscernible. In conclusions, chronic intake of higher doses of DU (300 mg/kg) had a significant impact on the immune function, most likely due to an imbalance in T helper (Th) 1 and Th2 cytokines.

Immunological Changes Associated with Chronic Ingestion of Depleted Uranium in Rats.

ABSTRACT: The objective of this study was to evaluate the effect of depleted uranium (DU) on the rat immune system. Three-wk-old, specific pathogen-free Sprague-Dawley rats that received dietary DU for 4 mo were divided into four groups (30 rats per group) according to exposure dose: 0 (control group), 1.3 (DU1.3 group), 13 (DU13 group), and 130 mg U kg-1 (DU130 group). After 4 mo of exposure, the splenic tissues of the rats presented elevated uranium content in accordance with increasing dosage. The rats in the DU130 group exhibited immunological damage characterized by pathomorphological changes of immune organs and significantly lower thymic and splenic relative weight, whereas the influences of DU on the immune system were slight in the other groups. In addition, higher uranium exposure also resulted in reduced numbers of peripheral lymphocytes, lower lymphocyte proliferation, and reduced paw swelling. The authors concluded that the influences of DU on the immune system were slight after ingestion of DU at lower doses but severe after exposure to DU at higher doses.

The protective role of zinc against acute toxicity of depleted uranium in rats.

Depleted uranium (DU) has been widely used in both civilian and military activities and contributes to health problems. This study was undertaken to evaluate the protective role of zinc against acute toxicity of DU. Sprague Dawley rats were injected with DU (10 mg/kg, i.p.) to create a toxicity model (DU group). Before and after the injection of DU, zinc sulphate (10 mg/kg, i.p.) was administered once a day for 2 days. The survival rates at 30 days post DU administration and the effects of zinc at 4 days post DU administration were evaluated. Our data indicate that zinc has obvious protective effects, especially pre-treatment with zinc. Rats pre-treated with zinc had significantly higher survival rates than rats in the DU group, with 60.03% more surviving. In addition, at 4 days post DU administration, the former had lower kidney uranium content, insignificant renal tubular epithelial cell necrosis and less transparent tubes. Meanwhile, blood urea nitrogen, creatinine and urine N-acethyl-ß-d-glucosaminidase concentrations were significantly decreased; the gene expression levels of metallothionein (MT) in kidney tissues were significantly increased; and catalase levels were increased and malondialdehyde levels were decreased. In conclusion, pre-treatment with zinc significantly alleviated acute toxicity of DU, and the mechanism appeared to be related to the induction of MT synthesis and enhancement of the antioxidant function.

The reproductive effects in rats after chronic oral exposure to low-dose depleted uranium.

This two-generation study evaluated the effects of depleted uranium (DU) on reproduction in rats. Across two generations, Wistar rats (30/sex/group) were maintained on feed containing DU at dose levels of 0 (control group), 4 (DU4 group), or 40 (DU40 group) mg kg⁻¹ day⁻¹ for 4 months prior to mating. After 4 months of exposure, the pregnancy rate, normal labour rate, and survival rate of offspring produced by F1 rats were all significantly decreased as compared to the control group, and especially in the DU40 group, these parameters fell by half to two-thirds, while no adverse effects were evident in F0 rats. The uranium content in the testes and ovaries of F1 rats in the DU4 and DU40 groups was significantly higher than that found in F0 rats. The levels of sex hormone in the serum were disorder in both generations. The enzymes related to spermiogenesis were also significantly different between generations, and the damage was more severe in F1 rats. In conclusion, the reproductive effects in F0 rats were slight after chronic oral exposure to DU, while the effects were obvious in F1 rats.

A study assessing the genotoxicity in rats after chronic oral exposure to a low dose of depleted uranium.

PURPOSE: The aim of this study was to evaluate the potential genotoxicity induced by chronic oral exposure to depleted uranium (DU). MATERIALS AND METHODS: Weanling Wistar rats (F(0)), 50/sex/group, were exposed to DU in food at doses of 0, 4, or 40 mg kg(-1)day(-1) for four months. They were subsequently mated, resulting in the birth of F(1) rats. Fifty F(l) weanlings/sex/group were exposed for four months to the same dose levels as their parents. After four months, the uranium content in the tissues, the potential damage to the genetic material, and pathomorphological changes of the testicles were observed in both F(0) and F(1) rats. The genotoxicity of DU was evaluated by the following methods: sperm abnormality assessment, the bone-marrow micronucleus test, and the comet assay. RESULTS: Uranium content in F(1) rats was significantly higher than that in F(0) rats in both the kidney and ovary (p < 0.05). The sperm abnormality rate, marrow cell micronuclei rate, comet tail length, and tailed cell percentage increased in each treatment group in each generation compared with the control group (p < 0.05). When comparing F(1) with F(0) rats, significant differences were detected for most of the indicators, with F(1) rats always exhibiting more damage (p < 0.05). With regard to pathomorphological changes in the testicles, the sperm displayed atypical changes, including thickening of the anachromasis nucleolus, which seemed to be more severe in F(1) rats. CONCLUSION: Genotoxicity may be induced in rats after chronic oral exposure to a low dose of DU.