Involvement of Akt/GSK3ß/CREB signaling pathway on chronic omethoate induced depressive-like behavior and improvement effects of combined lithium chloride and astaxanthin treatment.

Chronic organophosphorus pesticides (OP) exposure is associated with an increased risk of depression, and there is an urgent need to find an effective treatment for the depressive-like symptoms caused by OP. The main purpose of this study was to investigate whether combined lithium chloride (LiCl) and astaxanthin (AST) treatment would manifest synergetic antidepressant effects on mice with chronic OP exposure, and to determine the role of the Akt/GSK3ß/CREB signaling pathway. Our results showed that chronic omethoate exposure significantly increased immobility time in behavioral tests and induced neuron damage in HE staining. The expression of p-GSK3ß, p-CREB, p-PI3K and p-Akt in hippocampus after OP exposure were significantly down-regulated, while the influences were reversed by LiCl and AST treatment. Moreover, the combined application of AST and LiCl had synergistic therapeutic effects compared to LiCl and AST treatment alone, the expression of p-GSK3ß, p-CREB, p-PI3K and p-Akt after combined LiCl-AST treatment were significantly higher than that with single drug application. These results showed that the combination of LiCl and AST could efficiently ameliorate depressive-like behavior induced by omethoate, and Akt/GSK3ß/CREB signaling pathway might be responsible for the neuroprotective effect.

Neuregulin1ß improves cognitive dysfunction and up-regulates expression of p-ERK1/2 in rats with chronic omethoate poisoning.

OBJECTIVE: To observe the effects of neuregulin1ß (NRG1ß) on the level of phosphorylated ERK1/2 (p-ERK1/2), and explore the therapeutic mechanism of NRG1ß on the cognitive dysfunction in rats with chronic omethoate poisoning. METHODS: Rats with strong learning and memory ability, 50 in total, were selected by Y-electric maze test. Among which, 15 rats were randomly selected into control group, and the rest 35 rats were used to establish experimental cognitive impairment models by being injected with omethoate subcutaneously. The 30 cases of successful cognitive impairment models were randomly divided into model group and treated group consisting of 15 rats, respectively. Then rats in treated group were injected with NRG1ß into their lateral ventricles, while rats in control and model groups were given equal volume of PBS simultaneously. The cognitive capacity of rats was evaluated with Y-electric maze. The morphology and ultrastructure of hippocampus were observed by hematoxylin eosin (HE) staining and transmission electron microscopy (TEM) respectively. The expression of p-ERK1/2 was determined by immunohistochemical (IHC) staining and Western blotting. RESULTS: Compared with rats in model group, the cognitive ability of rats with omethoate exposed (model and treated groups) reduced significantly, along with the obvious damage of hippocampal neurons and the expression of p-ERK1/2 decreased significantly (P < 0.05). And after treatment with NRG1ß, the cognitive activity of treated rats was improved obviously, and the injury of hippocampal neurons was milder and the expression of p-ERK1/2 increased significantly more than those in model rats (P < 0.05). CONCLUSION: In chronic omethoate poisoning rats, NRG1ß can promote the phosphorylation level of ERK1/2 in hippocampal neurons, and play an important role in the improvement of cognitive function.

Banded structures in collagen vitrigels for corneal injury repair.

There is a growing interest in using collagen vitrigels for corneal injury repair. We recently reported the synthesis and thermal denaturation behavior of these gels. In this paper, the banded structure in these vitrified gels is studied by small-angle X-ray scattering (SAXS) one-dimensional (1-D) correlation function analysis and transmission electron microscopy (TEM). Results demonstrate that the collagen vitrigel possess banded structures similar to those of the starting type I collagen, with an average D-spacing of 64nm (by SAXS) or 57nm (by TEM). A combination of SAXS 1-D correlation function analyses and TEM show that overlap and gap distances ranged from 30 to 33nm and from 23 to 25nm, respectively. Changing the vitrification condition does not impact on the banded structure significantly.

Effects of molecular geometry on the self-assembly of giant polymer-dendron conjugates in condensed state.

A series of giant polymer-dendron conjugates with a dendron head and a linear polymer tail were synthesized via"click" chemistry between azide-functionalized polystyrene (PS(N), N: degree-of-polymerization) and t-butyl protected, alkyne-functionalized second generation dendron (tD), followed by a deprotection process to generate a dendron termini possessing nine carboxylic acid groups. The molecular structures were confirmed by nuclear magnetic resonance, size-exclusion chromatographic analyses, and matrix-assisted laser desorption ionization time-of-flight mass spectra. These well-defined conjugates can serve as a model system to study the effects of the molecular geometries on the self-assembly behaviour, as compared with their linear analogues. Four phase morphologies found in flexible linear diblock copolymer systems, including lamellae, bicontinuous double gyroids, hexagonal packed cylinders, and body-centred cubic packed spheres, were observed in this series of conjugates based on the results of small angle X-ray scattering and transmission electron microscopy. All of the domain sizes in these phase separated structures were around or less than 10 nm. A 'half' phase diagram was constructed based on the experimental results. The geometrical effect was found not only to enhance the immiscibility between the PS(N) tail and dendron head, but also systematically shift all of the phase boundaries towards higher volume fractions of the PS(N) tails, resulting in an asymmetrical phase diagram. This study may provide a pathway to the construction of ordered patterns of sub-10 nm feature size using polymer-dendron conjugates.

Design and Synthesis of Network-Forming Triblock Copolymers Using Tapered Block Interfaces.

We report a strategy for generating novel dual-tapered poly(isoprene-b-isoprene/styrene-b-styrene-b-styrene/methyl methacrylate-b-methyl methacrylate) [P(I-IS-S-SM-M)] triblock copolymers that combines anionic polymerization, atom transfer radical polymerization (ATRP), and Huisgen 1,3-dipolar cycloaddition click chemistry. The tapered interfaces between blocks were synthesized via a semi-batch feed using programmable syringe pumps. This strategy allows us to manipulate the transition region between copolymer blocks in triblock copolymers providing control over the interfacial interactions in our nanoscale phase-separated materials independent of molecular weight and block constituents. Additionally, we show the ability to retain a desirous and complex multiply-continuous network structure (alternating gyroid) in our dual-tapered triblock material.

Competition between liquid crystallinity and block copolymerself-assembly in core-shell rod-coil block copolymers.

Core-shell type of architecture revealed the subtle competition between liquid-crystalline ordering and block copolymer (BCP) self-assembly in a rod-coil BCP system.

Structure study of cellulose fibers wet-spun from environmentally friendly NaOH/urea aqueous solutions.

In this study, structure changes of regenerated cellulose fibers wet-spun from a cotton linter pulp (degree of polymerization approximately 620) solution in an NaOH/urea solvent under different conditions were investigated by simultaneous synchrotron wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS). WAXD results indicated that the increase in flow rate during spinning produced a better crystal orientation and a higher degree of crystallinity, whereas a 2-fold increase in draw ratio only affected the crystal orientation. When coagulated in a H2SO4/Na2SO4 aqueous solution at 15 degrees C, the regenerated fibers exhibited the highest crystallinity and a crystal orientation comparable to that of commercial rayon fibers by the viscose method. SAXS patterns exhibited a pair of meridional maxima in all regenerated cellulose fibers, indicating the existence of a lamellar structure. A fibrillar superstructure was observed only at higher flow rates (>20 m/min). The conformation of cellulose molecules in NaOH/urea aqueous solution was also investigated by static and dynamic light scattering. It was found that cellulose chains formed aggregates with a radius of gyration, Rg, of about 232 nm and an apparent hydrodynamic radius, Rh, of about 172 nm. The NaOH/urea solvent system is low-cost and environmentally friendly, which may offer an alternative route to replace more hazardous existing methods for the production of regenerated cellulose fibers.