Protectin DX promotes epithelial injury repair and inhibits fibroproliferation partly via ALX/PI3K signalling pathway.

Acute respiratory distress syndrome/acute lung injury (ARDS/ALI) is histologically characterized by extensive alveolar barrier disruption and excessive fibroproliferation responses. Protectin DX (PDX) displays anti-inflammatory and potent inflammation pro-resolving actions. We sought to investigate whether PDX attenuates LPS (lipopolysaccharide)-induced lung injury via modulating epithelial cell injury repair, apoptosis and fibroblasts activation. In vivo, PDX was administered intraperitoneally (IP) with 200 ng/per mouse after intratracheal injection of LPS, which remarkedly stimulated proliferation of type II alveolar epithelial cells (AT II cells), reduced the apoptosis of AT II cells, which attenuated lung injury induced by LPS. Moreover, primary type II alveolar cells were isolated and cultured to assess the effects of PDX on wound repair, apoptosis, proliferation and transdifferentiation in vitro. We also investigated the effects of PDX on primary rat lung fibroblast proliferation and myofibroblast differentiation. Our result suggests PDX promotes primary AT II cells wound closure by inducing the proliferation of AT II cells and reducing the apoptosis of AT II cells induced by LPS, and promotes AT II cells transdifferentiation. Furthermore, PDX inhibits transforming growth factor-ß1 (TGF-ß1 ) induced fibroproliferation, fibroblast collagen production and myofibroblast transformation. Furthermore, the effects of PDX on epithelial wound healing and proliferation, fibroblast proliferation and activation partly via the ALX/ PI3K signalling pathway. These data present identify a new mechanism of PDX which targets the airway epithelial cell and fibroproliferation are potential for treatment of ARDS/ALI.

[Spectroscopy research on cholesterol in hypercholesterolemia serum].

The cholesterol with different concentration in hypercholesterolemia serum was studied by the method of spectroscopy technology. The absorption and fluorescence spectra of normal human serum and hypercholesterolemia serum were obtained respectively; the spectral characteristic of each sample and the difference between two kinds of samples were discussed too. The results indicate that the absorption and fluorescence spectra of hypercholesterolemia serum are different from those of normal human serum. The absorptivity and the fluorescence intensity of hypercholesterolemia serum are both higher than those of normal human serum. Besides, there are new absorptive peaks and new fluorescence peaks in the spectrogram. Thus, the abnormalism of cholesterol in serum can be judged by comparing the absorption and fluorescence spectra. The researches in the present paper provide an experimental foundation for the diagnosis of cholesterol in blood.

[Changes of thioredoxin mRNA level in neurons with mitochondrial dysfunction insulted by H2O2].

Oxidative stress and mitochondrial deficiency have been considered to be associated with the mechanisms of many neurodegenerative diseases. Sodium azide (NaN3) is a special inhibitor of mitochondrion cytochrome c oxidase (COX), which can be used to mimic neuronal damage induced by mitochondrial deficiency. In this experiment, the neurotoxic effects of H2O2 on primary cultured neurons and NaN3-induced mitochondrial dysfunctional neurons were detected by means of cell viability measurement (MTT) and analyzed through morphological observation. Furthermore, the changes of thioredoxin mRNA level in both normal and abnormal cultured neurons insulted by H2O2 were analyzed by semiquantitative RT-PCR in order to explore the role of Trx, an important redox regulatory protein, in modulating the process of neuronal injury. It was found that mitochondrial dysfunctional neurons could be damaged by H2O2 in a dose- and time-dependent manner and the expression of Trx decreased during certain dose (0-200 mumol/L) and time (0-4 h) of H2O2 treatment. But in normal neurons the effects of H2O2 treatment seemed to be less evident. It suggests that in neurons with mitochondrial dysfunction, the redox modulation of thioredox seems to be more prominent.

[Construction and identification of recombinant adenovirus vector containing thioredoxin reductase gene].

AIM: To construct recombinant adenovirus vector containing human thioredoxin reductase (TR) gene and to explore the correlation between antioxidant activity of TR and the degenerative neuropathy. METHODS: Full length TR cDNA was obtained from recombinant plasmid pGEM-TR via digestion with Apa I and Not I and was cloned into pShuttle vector and pShuttle-TR was recut with I-Ceu I and PI-Sce I. Fragment containing TR gene and CMV promoter was inserted into E1 and E3 deficient adeno-X virus DNA, and then the recombinant adenovirus vector was transfected into HEK 293 cells through lipofectamine and identified by PCR. The TR expression on and in cell lysate of CV1 cells infected with recombinant adenovirus was by immuno fluorescence assay and Western blot analysis. RESULTS: After replication of recombinant adenovirus Adeno-TR, the virus titer was about 4.4x10(11) pfu/L. The TR expression on CV1 cells was proved by fluorescent microscopy. Western blot analysis showed a band with relative molecular mass (M(r)) of 55,000. CONCLUSION: A recombinant adenovirus vector has been successfully constructed and TR is expressed on CV1 cells. This result lays the foundation for further study on function of TR and its correlation with degenerative neuropathy.

[Changes of thioredoxin mRNA level in neurons insulted by sodium azide].

Oxidative stress has been considered to be associated with many neurodegenerative diseases, while mitochondrial damage is one of the important reasons that aggravate oxidative stress. Sodium azide (NaN3) is a specific inhibitor of mitochondrial cytochrome c oxidase (COX), which can be used to mimic neuronal damage induced by mitochondrial deficiency. In this experiment, the neurotoxic effects of NaN3 on cultured primary neurons were detected by means of cell viability measurement (MTT assay) and morphological observation, and an in vitro model of neuronal injury induced by NaN3 were established. Further the changes of thioredoxin mRNA level in cultured neurons insulted by NaN3 were analyzed by semiquantitative RT-PCR in order to explore the role of Trx, an important redox regulatory protein, in the process of neuronal injury. It was found that cultured neurons could be damaged by NaN3 in a dose- and time-dependent manner and the expression of Trx decreased during certain dose (0-32mmol/L) and time (0-4hr) of NaN3 treatment. The above data suggest that decreased the expression of Trx may be associated with oxidative stress induced by neuronal respiratory chain injury, which could impair neuronal protective mechanism.