Histological changes, lipid metabolism, and oxidative and endoplasmic reticulum stress in the liver of laying hens exposed to cadmium concentrations

The objective of this study was to determine the effects of cadmium (Cd) on histological changes, lipid metabolism, and oxidative and endoplasmic reticulum (ER) stress in the liver of layers. A total of 480 hens at 38 wk of age were randomly assigned in 5 groups that were fed a basal diet or basal diet supplemented with CdCl₂ 2.5H₂O at 7.5, 15, 30, and 60 mg Cd/kg feed for 9 wk. The results showed that accumulation of Cd was the greatest in the kidney, followed by the liver, pancreas, and lung. Diet contaminated with 30 mg Cd/kg induced antioxidant defenses accompanied by the increase of the activities of antioxidant enzymes in the liver, while dietary supplementation with 60 mg Cd/kg decreased the antioxidant levels significantly (P < 0.05). Immunofluorescence assay showed Cd induced reactive oxygen species production and endoplasmic reticulum stress in hepatocytes. Exposure to 60 mg Cd/kg significantly upregulated the expression of cytochrome C, caspase 3, caspase 9, caspase 7, Grp78, and Chop (P < 0.05). Histopathology and quantitative real-time PCR results presented periportal fibrosis, bile duct hyperplasia, and periportal inflammatory cell infiltration in the liver accompanied by upregulating the expression of tumor necrosis factor-α, IL-6 and IL-10 in the 30- or 60-mg Cd/kg groups. Oil Red O staining and RT-qPCR results showed dietary supplementation with 7.5, 15, and 30 mg Cd/kg promoted the synthesis of lipid droplets and upregulated the expression of fatty acid synthase, while dietary supplementation with 60 mg Cd/kg attenuated the synthesis of lipid droplets and downregulated the expression of acyl-CoA oxidase 1, carnitine palmitoyltransferase-1, and perixisome proliferation-activated receptor α (P < 0.05). Besides, the expression of vitellogenin (VTG) II and microsomal triglyceride transfer protein were upregulated in the 7.5-mg Cd/kg group, and the expressions of apolipoprotein B, vitellogenin II, and apolipoprotein very-low-density lipoprotein-II were downregulated in the 30- and/or 60-mg Cd/kg groups (P < 0.05). Conclusively, although low-dose Cd exposure promoted the synthesis of lipids and lipoproteins in the liver, the increase of Cd exposure could trigger liver injury through inducing oxidative and endoplasmic reticulum stress and negatively affect lipid metabolism and yolk formation in laying hens.

Antitumour activity of 3-nitropropionic acid from Phomopsis sp. and optimization of fermentation conditions

In this study, 3-nitropropionic acid (3-NPA) was separated and purified from endophytic fungi belonging to Phomopsis sp. and its cytotoxicity was determined by MTT assay. Treatment with 3-NPA for 24 h resulted in a dose-dependent apoptosis in MCF-7 cells. Through quantitative detection of the genes that are closely related to the Bcl-2 signalling pathway, there was an increased expression of p53 and Bax and a decreased expression of Bcl-2, which indicated apoptosis in these cells. Meanwhile, the overexpression of PARA (poly ADP-ribose polymerase) and apoptosis inducing factor (AIF) also suggested that 3-NPA induced cellular apoptosis through a caspase-3-independent pathway in caspase-3-deficient MCF-7 cells. The fermentation condition was also improved to produce more 3-NPA: glucose as a carbon source and yeast extract as a nitrogen source, fermentation for 8 days at 32°C and a solution environment of pH 5·0. Under these conditions, the yield of 3-NPA was increased to 529 mg l(-1) compared with 410 mg l(-1) under traditional fermentation conditions.

SIGNIFICANCE AND IMPACT OF THE STUDY

3-Nitropropionic acid is a mitochondrial inhibitor and has some useful bioactivities such as antibacterial activity. In this paper we found that 3-NPA also has obvious cytotoxicity, so we studied its antitumour activity and tried to determine the antitumour molecular mechanism, opening a new perspective for potential antitumour prodrug development. As 3-NPA is often obtained from natural products with a low yield, in order to overcome the disadvantage of an endophytic fungi source of 3-NPA, we optimized the fermentation conditions for 3-NPA in Phomopsis sp. to obtain the maximum production of 3-NPA.

Inelastic x-ray scattering study of exciton properties in an organic molecular crystal

Excitons in a complex organic molecular crystal were studied by inelastic x-ray scattering (IXS) for the first time. The dynamic dielectric response function is measured over a large momentum transfer region, from which an exciton dispersion of 130 meV is observed. Semiempirical quantum chemical calculations reproduce well the momentum dependence of the measured dynamic dielectric responses, and thus unambiguously indicate that the lowest Frenkel exciton is confined within a fraction of the complex molecule. Our results demonstrate that IXS is a powerful tool for studying excitons in complex organic molecular systems. Besides the energy position, the IXS spectra provide a stringent test on the validity of the theoretically calculated exciton wave functions.

[Experimental study on application of allogeneic bone matrix gelatin in the intervertebral fusion]

OBJECTIVE

To testify the inductive osteogenesis of allogeneic bone matrix gelatin (BMG) in promoting intervertebral fusion.

METHODS

The gelatin sponge, allogeneic BMG, decalcified bone matrix (DBM) and alcohol conserved bone were implanted respectively into the intervertebral space of rabbit, whose intervertebral discs were removed before implantation. The intervertebral spaces were evaluated by X-ray and histological examination at 4, 8, and 12 weeks after operation.

RESULTS

No obvious immune rejection was observed. Amounts of new bone were formed in the intervertebral spaces at 4 and 8 weeks. And complete infusion of the intervertebral spaces were appeared at 12 weeks.

CONCLUSION

Allogeneic BMG can promote bone fusion of intervertebral spaces through osteoinduction, which suggests that allogeneic BMP is an ideal substitute for bone replacement.