PRDX1 exerts a photoprotection effect by inhibiting oxidative stress and regulating MAPK signaling on retinal pigment epithelium.

BACKGROUND: The purpose of this study was to investigate the photoprotection effect of peroxiredoxin 1 (PRDX1) protein in ultraviolet B (UVB) irradiation-induced damage of retinal pigment epithelium (RPE) and its possible molecular mechanism. METHODS: ARPE-19 cell viability and apoptosis were assessed by MTT assay and flow cytometry, respectively. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the PRDX1 expression. The corresponding kits were employed to measure the levels or activities of lactate dehydrogenase (LDH), 8-hydroxy-2-deoxyguanosine (8-OHdG), reactive oxygen species (ROS), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD). Western blotting was applied to examine PRDX1 expression and mitogen-activated protein kinase (MAPK) signaling pathway-related proteins. RESULTS: After exposure to 20 mJ/cm2 intensity of UVB irradiation for 24 h, ARPE-19 cells viability was decreased, the leakage degree of LDH and 8-OHdG were increased, and cell apoptosis was elevated. The expression of PRDX1 was significantly down-regulated in UVB-induced ARPE-19 cells. The low expression of PRDX1 was involved in high irradiation intensity. Overexpression of PRDX1 increased cell activity, decreased cell apoptosis, and LDH as well as 8-OHdG leakage in UVB-induced ARPE-19 cells. In addition to alleviating UVB-induced cell damage, PRDX1 overexpression also inhibited UVB-induced oxidative stress (down-regulation of ROS and MDA levels, up-regulation of GSH-Px and SOD activities) and the activation of MAPK signaling pathway in ARPE-19 cells. CONCLUSION: PRDX1 exerts a photoprotection effect on RPE by attenuating UVB-induced cell damage and inhibiting oxidative stress, which can be attributed to the inhibition of MAPK signaling pathway activation.

[Efficacy and safety of Xiyanping injection combined with azithromycin in treating mycoplasma pneumonia of children: Meta-analysis].

To systemically evaluate the safety and efficacy of Xiyanping injection combined with azithromycin in the treatment of mycoplasmal pneumonia in children. PubMed, Wanfang Data, CNKI, VIP and CBM were used to search for the clinical randomized controlled trials on Xiyanping injection combined with azithromycin in the treatment of mycoplasmal pneumonia in children from database establishment to July, 2017. The papers were screened according to the established inclusion and exclusion criteria, and then the quality of the included studies was evaluated to extract valid data for Meta-analysis by using Revman 5.3 software. A total of 31 clinical randomized controlled trials were included, involving 2 881 patients. Meta-analysis showed that as compared with azithromycin alone, the combination of azithromycin with azithromycin had obvious advantages in the total effective rate（OR=5.42,95%CI[3.98,7.38],P<0.000 01）, fever clearance time（MD=-1.29,95%CI[-1.51,-1.08],P<0.000 01）, cough disappearance time （MD=-1.72,95%CI[-1.99,-1.46],P<0.000 01）, lung wet rales disappearance time（MD=-1.51,95%CI[-1.88,-1.14],P<0.000 01）, chest X-ray recovery time（MD=-2.72,95%CI[-3.82,-1.63],P<0.000 01）, shortening the hospital stay（MD=-1.88,95%CI[-2.26,-1.50],P<0.000 01）, reducing the incidence of adverse reactions（MD=0.51,95%CI[0.33,0.79],P=0.002）, and other aspects, with statistically significant difference. Based on the existing evidences, Xiyanping injection combined with azithromycin in the treatment of mycoplasmal pneumonia in children can significantly improve the overall clinical efficiency, shorten the hospital stay and reduce the incidence of adverse reactions. However, the clinical trials of existing small randomized controlled trials have low quality of methodology and require a large sample of high quality clinical trials for further validation.

Differential distribution patterns of ammonia-oxidizing archaea and bacteria in acidic soils of Nanling National Nature Reserve forests in subtropical China.

In addition to ammonia-oxidizing bacteria (AOB) the more recently discovered ammonia-oxidizing archaea (AOA) can also oxidize ammonia, but little is known about AOA community structure and abundance in subtropical forest soils. In this study, both AOA and AOB were investigated with molecular techniques in eight types of forests at surface soils (0-2 cm) and deep layers (18-20 cm) in Nanling National Nature Reserve in subtropical China. The results showed that the forest soils, all acidic (pH 4.24-5.10), harbored a wide range of AOA phylotypes, including the genera Nitrosotalea, Nitrososphaera, and another 6 clusters, one of which was reported for the first time. For AOB, only members of Nitrosospira were retrieved. Moreover, the abundance of the ammonia monooxygenase gene (amoA) from AOA dominated over AOB in most soil samples (13/16). Soil depth, rather than forest type, was an important factor shaping the community structure of AOA and AOB. The distribution patterns of AOA and AOB in soil layers were reversed: AOA diversity and abundances in the deep layers were higher than those in the surface layers; on the contrary, AOB diversity and abundances in the deep layers were lower than those in the surface layers. Interestingly, the diversity of AOA was positively correlated with pH, but negatively correlated with organic carbon, total nitrogen and total phosphorus, and the abundance of AOA was negatively correlated with available phosphorus. Our results demonstrated that AOA and AOB were differentially distributed in acidic soils in subtropical forests and affected differently by soil characteristics.