Improvement of rat hepatocellular carcinoma model induced by diethylnitrosamine.

OBJECTIVE: To construct a new diethylnitrosamine (DEN)-induced rat hepatocellular carcinoma (HCC) model with short induction time, high incidence, and survival rate. METHODS: 60 male Sprague-Dawley rats were randomly divided into 4 groups: the control group, the model A (MA) group, the model B (MB) group, and the model C (MC) group. The control group was intraperitoneally injected with 0.9% saline for 6 weeks. The MA group was injected with the DEN solution at 30 mg/kg three times a week for 6 weeks. The MB group was injected with the DEN solution at 30 mg/kg three times a week for 6 weeks, and discontinued the induction for 2 weeks. The MC group was injected with the DEN solution at 30 mg/kg three times a week for 8 weeks. The levels of albumin (ALB), alanine transaminase (ALT), and aspartate aminotransferase (AST) in serum were assayed. Meanwhile, the pathological conditions, apoptosis of hepatocytes, expression of NF-κBp65, and the reactive oxygen species level were detected. RESULTS: All rats in the control group and the MA group survived, and none of the rats occurred HCC. HCC occurred in rats of the MB group and the MC group. The serum ALB level in the MB group was higher than that in the MC group. The serum ALT and AST levels and the number of proliferating and apoptotic hepatocyte cells in the MB group were lower than those in the MC group. The expression of ROS- and NF-κBp6- positive cells in the MA group, MB group, and MC group were significantly higher than that of the control group. CONCLUSION: This study developed a new DEN-induced rat HCC model with short induction time, high incidence, and survival rate. NF-κB pathway may be one of the main pathways involved in the development of this model.

Intravenous Immunoglobulin Inhibits Liver Cancer Progression by Promoting p38MAPK-Associated Apoptosis.

Objective: The aim of this study is to explore the effect of intravenous immunoglobulin (IVIG) on the development of rat hepatocellular carcinoma and its possible molecular mechanism. Methods: Sixty adult male Sprague-Dawley (SD) rats were randomly divided into three groups: control, diethylnitrosamine(DEN) + normal saline(NS), and DEN + IVIG groups, with 20 rats in each group. The rats in the DEN + NS group and DEN + IVIG group were given DEN 0.2 g/kg intraperitoneal injection once on day 1 and then 0.05% DEN aqueous solution in drinking water to establish a rat liver cancer model. Immunoglobulin (IgG) was injected intraperitoneally into the DEN + IVIG group twice a week at the dose of 100 mg/kg, and saline was administered intraperitoneally into the control group at a 50 mg/kg dosage. The body weight of each group of rats was recorded twice a week. All treatments were maintained continuously for 12 weeks. After the intervention, the liver function indexes of rats were measured by a fully automated biochemical analysis instrument. The liver histopathology was observed by hematoxylin-eosin(HE) staining. Immunohistochemistry was used to detect c-myc protein expression, and Western blotting was used to determine p38MAPK and p-p38MAPK protein expressions, as well as apoptosis-related proteins such as Bcl-2, Bax, and cleaved caspase-3. Results: Compared with the rats in the DEN + NS group, rats in the DEN + IVIG group showed substantially higher body mass (P < 0.05), higher survival rate (P < 0.05), and lower liver function indexes (P < 0.05). Few focal necrosis of cancer cells and few nuclear division were observed in the rats in the DEN + IVIG group. The rats in the DEN + NS group showed lamellar necrosis of cancer foci, destruction of normal liver lobular structure, and hepatocellular carcinoma cells. Immunohistochemical analysis results revealed that the expression of c-myc was reduced in the DEN + IVIG group (P < 0.05), and Western blotting confirmed that the Bcl-2 expression was decreased (P < 0.05), while Bax, p38 MAPK, p-p38 MAPK, and cleaved caspase-3 protein expressions were increased (P < 0.05). Conclusion: IVIG prophylactic injection can delay tumor development and induce apoptosis in primary hepatocellular carcinoma in rats. The mechanism is connected to the activation of the p38MAPK signaling pathway by upregulating the level of cleaved caspase-3 and Bax proteins while downregulating the level of Bcl-2 and c-myc proteins.

Intravenous immunoglobulin is effective in alleviating hepatic ischemia-reperfusion injury: a rat model study.

BACKGROUND: Hepatic ischemia-reperfusion injury (I/R) is an important factor affecting the prognosis of patients undergoing liver surgery. This study aimed to explore the value of intravenous immunoglobulin (IVIG) in hepatic I/R and its mechanism in a rat model. MATERIALS AND METHODS: Forty eight adult male Sprague-Dawley (SD) rats were divided into six groups randomly: (1-2) treated with normal saline (NS) without ischemia or reperfusion; (3-4) treated with NS + 30 min ischemia; (5-6) treated with IVIG + 30 min ischemia. Rats of group 1/3/5 were euthanized at 12 h after operation (sham + NS + 12 h, I/R + NS + 12 h, I/R + IVIG + 12 h group) while group 2/4/6 were euthanized at 24 h (sham + NS + 24 h, I/R + NS + 24 h, I/R + IVIG + 24 h group). Interleukin 10 (IL-10), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) were quantified as well as serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Hepatic pathological changes were observed while nuclear factor kappa B p65 (NF-κB p65), Inhibitory Subunit of NF Kappa B Alpha (IKB-alpha) and cleaved caspase-3 were detected. CONCLUSION: ALT, AST, IL-6, TNF-alpha, NF-κB p65 and cleaved caspase-3 were increased by I/R whereas IL-10 and IKB-alpha were decreased. However, IVIG pretreatment reduced ALT, AST, IL-6, TNF-alpha, NF-κB p65 and cleaved caspase-3, but increased IL-10 and IKB-alpha. IVIG treatment attenuates the infiltration of inflammatory cell and cell apoptosis which were observed in I/R groups. IVIG may alleviate hepatic I/R in rats by inhibiting the classical NF-κB signaling pathway, reducing IL-6, TNF-alpha, promoting IL-10, and inhibiting cell apoptosis.

Synthesis, characterization and antibacterial study on the chitosan-functionalized Ag nanoparticles.

This study provided a facile, one-step hydrothermal method to synthesize stable Ag colloid in aqueous solution by utilizing chitosan as both reductant and stabilizer. The formation of chitosan-functionalized Ag nanoparticles was verified by UV-Vis, FTIR, TEM, AFM and XRD measurements. FTIR results revealed that the primary amine groups and amide groups of chitosan have specific interactions with the surface of Ag nanoparticles. The average diameter of the Ag nanoparticles is 10.0±5.4nm as determined by TEM. Ag nanoparticles are highly crystalline as revealed by HR-TEM and XRD measurements. The size and shape of Ag nanoparticles are also found to depend on the pH condition in the synthesis. Ag nanoparticles were the main products at pH5.0 whereas large Ag nanotriangle and truncated triangular nanoplate were dominant at pH4.0 in the synthesis. Due to its monodispersity and good stability, the chitosan-functionalized Ag colloid synthesized at pH5.0 was further tested for its antibacterial activities against gram-positive bacteria, gram-negative bacteria and fungus. The results of zone of inhibition, inhibition ratio and SEM characterization revealed that chitosan-functionalized Ag nanoparticles have great bactericidal efficiency against both bacteria and fungus.

Structural study on the interactions of oxaliplatin and linear DNA.

Damage to cellular DNA is believed to determine the cytotoxicity of oxaliplatin. However, high resolution structures formed by oxaliplatin and different linear DNA remain unclear. This study characterized, the key structures of different linear DNA in the platination process by UV absorption spectra and atomic force microscopy (AFM). Bathochromic shift and hyperchromicity in UV spectra after addition of oxaliplatin revealed that it can disrupt base stacking of DNA in the platination process. AFM results of different linear DNA indicated that, the platination process can induce DNA change from an extended conformation to the network structure with many kinks and finally to the compact particles, or toroids with increasing the incubation time. All AFM results confirmed that, platination of different linear DNA by oxaliplatin is a time depended process. The present AFM results provide, structural evidence about the interactions between oxaliplatin and different linear DNA containing multiple targets. SCANNING 38:880-888, 2016. © 2016 Wiley Periodicals, Inc.

Study on water-dispersible colloids in saline-alkali soils by atomic force microscopy and spectrometric methods.

Recent studies have revealed that water-dispersible colloids play an important role in the transport of nutrients and contaminants in soils. In this study, water-dispersible colloids extracted from saline-alkali soils have been characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV absorption spectra. AFM observation indicated that the water-dispersible colloids contain some large plates and many small spherical particles. XRD, XPS, and UV absorption measurement revealed that the water-dispersible colloids are composed of kaolinite, illite, calcite, quartz and humic acid. In addition, UV absorption measurement demonstrated that the humic acids are associated with clay minerals. Water-dispersible colloids in the saline-alkali soils after hydrolyzed polymaleic anhydride treatment and an agricultural soil (nonsaline-alkali soil) were also investigated for comparison. The obtained results implied that the saline-alkali condition facilitates the formation of a large quantity of colloids. The use of AFM combined with spectrometric methods in the present study provides new knowledge on the colloid characteristics of saline-alkali soils. Microsc. Res. Tech. 79:525-531, 2016. © 2016 Wiley Periodicals, Inc.

Study on the interactions between anti-cancer drug oxaliplatin and DNA by atomic force microscopy.

Oxaliplatin is one of the most important anticancer drugs at present. However, the mechanism of action of oxaliplatin is still controversial. In this study, the interactions between oxaliplatin and a plasmid DNA have been studied so as to reveal the structural basis of its activity. The structural characteristic of pUC19 DNA (2ng/µL) incubated with 100µmol/L and 1000µmol/L of oxaliplatin for the different time on a freshly cleaved highly ordered pyrolytic graphite (HOPG) surface was investigated by atomic force microscopy (AFM). High resolution AFM observation indicated that oxaliplatin can induce pUC19 DNA molecules change from the extended conformation to the entangled structures with many nodes, and finally to the compact particles. The present AFM results provide structural evidence about the interactions between oxaliplatin and circular duplex DNA containing multiple targets.

Adsorption of human serum albumin onto highly orientated pyrolytic graphite surface studied by atomic force microscopy.

It is important to know the adsorption behavior and assembly structure of human serum albumin (HSA) molecules onto a carbonaceous substrate for further application of carbon nanomaterials in biomedical field. Individual HSA molecules and oligmers (dimer and trimer) adsorbed onto HOPG surface have been imaged by atomic force microscopy (AFM). Individual HSA molecule appeared as an ellipsoid on HOPG surface with average length of 12.6, width of 6.5, and height of 1.9 nm when they were incubated at the physiological condition (pH 7.4). HSA molecules also can form the interconnected chains, uniform network, and monolayer by tuning the initial concentrations and adsorption time. Furthermore, HSA molecules can assemble into quite different network structures and irregular chains at pH of 2, 5, and 10. This study could expand our knowledge of the interactions between protein and carbonaceous surfaces.

Structural changes of linear DNA molecules induced by cisplatin.

Interaction between long DNA molecules and activated cisplatin is believed to be crucial to anticancer activity. However, the exact structural changes of long DNA molecules induced by cisplatin are still not very clear. In this study, structural changes of long linear double-stranded DNA (dsDNA) and short single-stranded DNA (ssDNA) induced by activated cisplatin have been investigated by atomic force microscopy (AFM). The results indicated that long DNA molecules gradually formed network structures, beads-on-string structures and their large aggregates. Electrostatic and coordination interactions were considered as the main driving forces producing these novel structures. An interesting finding in this study is the beads-on-string structures. Moreover, it is worth noting that the beads-on-string structures were linked into the networks, which can be ascribed to the strong DNA-DNA interactions. This study expands our knowledge of the interactions between DNA molecules and cisplatin.

[Niche analysis of phytoplankton's dominant species in Dianshan Lake of East China].

By using modified Levins and Petraitis formulae, this paper determined the niche breadth and niche overlap of the phytoplankton's dominant species in Dianshan Lake of East China, and analyzed the relationships between the niche breadth and niche overlap and the density and dominance of the dominant species. The niche breadth and niche overlap of the dominant species differed in different periods, and different dominant species had different adaptive capacity to the environmental factors. Based on their niche breadth in different seasons, the dominant species in the Lake could be classified into four groups, among which, Chroomonas acuta and Chlorella vulgaris had broader niche, more quantity, wider distribution, and better use of environmental resources. During cyanobacterial blooms, the niche overlap among Cyanophyta species was comparatively higher, Microcystis aeruginosa had broader niche breadth, but other species showed lower niche breadth. Correlation analysis showed that the dominance of the dominant species in different seasons had significant correlation with their niche breadth, and the dominant species density had significant correlation with their niche overlap.

[Biological synthesis of L-ascorbyl palmitate].

Biological synthesis of L-Ascorbyl Palmitate in organic system were studied in this text. The contradiction between conversion of vitamin C and concentration of L-Ascorbyl Palmitate were resolved. High conversion of vitamin C and concentration of L-Ascorbyl Palmitate were obtained by Novo435. A series of solvents(log P from -0.24 to 3.5 )were investigated for the reaction,and acetone was found to be the most suitable from the standpoint of the enzyme activity and solubility of L-ascorbic. And the equilibrium of the reaction was affected by the addition of the molecular sieves and temperature. Reaction carried out at 60 degrees C and with 20% 0.4nm molecular sieves is good for the enzyme to keep its activity and for making the equilibrium go to the product. With 1.094 g palmitic acid, 0.107 g vitamin C and 0.020 g Novo435, rotate rate of 200 r/min, the conversion of ascorbic reached 80% and the concentration of L-ascorbyl palmitate is 20 g/L after 48 h. Furthermore, reaction batch of Novo435 and substrates recycle were observed, the result indicated that Novo435 may used 4-5 times continuously with high conversion. And 6-O-unsaturated acyl L-ascorbates were synthesized through Novo435 condensation of ascorbic acid and various unsaturated fatty acids with high conversion in this text.