Establishment and application of activity determining methods for different subtypes of xanthine oxidoreductase / 药学学报

Xanthine oxidoreductase (XOR), the key enzyme catalyzing purine to produce uric acid, including two subtypes, xanthine dehydrogenase (XDH) and xanthine oxidase (XO), respectively, in vivo. Usually, XDH and XO can transform to each other. In this study, based on the principle that the subtype XO or XDH uses different electron acceptors, the methods for the measuring the activities of bovine milk XOR (pure enzyme) and its subtypes were established. The optimal concentrations of substrate xanthine (50 μmol·L-1) and electron acceptor NAD+ (50 μmol·L-1), pH value (7.80) were investigated. The ranges of the XOR, XO, XDH activity which could be determined were 0.97-17.5 U·L-1, 1-9 U·L-1, and 66-1 191 mU·L-1, respectively. Furthermore, the methods for determining the activities of XOR and its subtypes in mouse liver were established. The preparation of liver samples, the optimal concentrations of xanthine (100 μmol·L-1) and NAD+ (100 μmol·L-1) were researched. And the activity ranges of XOR, XO and XDH in mouse liver which could be determined were 0.67-3.98, 0.19-1.08, and 0.52-3.55 U·gprot-1, respectively. With the methods above, the effects of classic XOR inhibitor allopurinal (Allo) on XOR, XO and XDH from both milk and mouse liver were determined. All animal experiments have been approved by the Animal Experimental Center, Institute of Materia Medica, Chinese Academy of Medical Science and Peking Union Medical College (00003346). This study established new methods for the determination of XOR and its subtypes activity in pure enzyme system and in mouse liver, respectively, which were accurate and convenient. It laid the experimental foundation for exploring the different pathophysiological effects of XOR in the body and developing new XOR inhibitors.

Ecological quality and its relationships with human activities in China-Laos railway economic belt.

Regional ecological quality is largely affected by human activities, which restricts the sustainable development of regional economy. Taking the China-Laos railway economic belt as an example, we investigated the effects of human activities on ecological quality. The remote sensing images of 1999, 2009 and 2019 were selected to calculate remote sensing ecological index (RSEI). Spatial autocorrelation statistics and local G statistics were used to explore the spatial-temporal variations of ecological quality in the study area. Combined with the population density in the same period, a geographically weighted regression model was constructed to quantitatively analyze the ecological effects of different human activity intensities in the study area. The results showed that the ecological quality in the study area presented a trend of increasing firstly and then decreasing later from 1999 to 2019, and that the mean value of RSEI varied from 0.645 (1999) to 0.738 (2009) and then decreasing to 0.721 in 2019. Specially, the ecological quality fluctuated more apparently in the midlands. The results of fitting population density and ecological quality based on geographical weighted regression model (GWR) were significantly better than that of least square method. R2 of different periods based on GWR was higher than 0.7 and the fitting effect was stable. The fitting degree of GWR in 2019 was the best (R2 was 0.785), and R2 in 1999 and 2009 were 0.726 and 0.754, respectively. The ecological quality along the China-Laos railway south area (such as Vientiane) was more sensitive to human activities, with most of these places belonged to moderately sensitive regions. For the highly, moderately and lowly ecological sensitive regions, every 10, 100, 1000-fold increases in population density would lead to a decrease of 0.2, 0.4 and 0.6 to the mean value of RSEI in turn. The development of economic belt would increase population density. During the planning and layout of economic belt, human activities should be controlled to avoid the deterioration of ecological quality in the potential and current sensitive regions.

The anti-hyperuricemic effects of compound CC18022 targeting xanthine oxidase / 药学学报

Hyperuricemia is not only the biochemical basis of gout, but also closely related to the development of metabolic syndrome, cardiovascular diseases, chronic kidney disease, etc. Xanthine oxidase (XOD) is the key catalytic enzyme for uric acid biosynthesis, therefore the vital target for anti-hyperuricemic drugs. In this study, compound CC18022 was designed and synthesized specifically targeting to XOD. Molecular docking analysis indicated a fairly tight binding between CC18022 and XOD. In the in vitro study, CC18022 significantly inhibited XOD activity with a half maximal inhibitory concentration (IC50) value in the order of nmol·L-1, which is relative to the XOD inhibitor febuxostat. By using both acute and chronic hyperuricemic mice model, compound CC18022 was found to have serum uric acid-lowering effect in a dose-dependent manner in vivo. The animal welfare and experimental processes were in accordance with the provisions of the Animal Ethics Committee of the Institute of Materia Medica, Chinese Academy of Medical Sciences. In the acute hyperuricemic mice, CC18022 significantly inhibited serum XOD activity, and also the XOD activity in intestine and liver, which were related to purine absorption and metabolism. Therefore, the novel compound CC18022 exhibited significant inhibition on XOD activity and anti-hyperuricemic effects, making it a favorable candidate for further research.

[Investigation on the Emission Difference of Air Pollutants from Common Residential Coal Stoves and Suggestions for Emission Reduction].

To explore the difference in the emission of air pollutants from coal stoves, five new and common residential coal stoves (square briquette, baffled heat exchange, heating and cooking integrated gasification positive burning, and gasification reverse burning stove) were selected. The emission level of major air pollutants was determined using simulated combustion in the laboratory for quantitatively evaluating the environmental effects of different coal stoves. Moreover, the factors and reasons for the differences were identified, and suggestions for the reduction of emission were proposed. The results showed that: ① the emissions of air pollutants from different coal stoves were significantly different; the heating and cooking integrated stove had the largest emission intensity (2.9 kg ·t-1) of air pollutants (SO2, NOx, and TSP), which was 1.6 times of the average value, and the square briquette stove had the lowest emission level, which was 65% of the average value. ② The emissions of gaseous pollutants from the coal stoves in different combustion stages also showed evident differences. In the high-fire stage, the NOx emission concentration of the square briquette stove was 0.49 mg ·m-3, which was 45%-72% lower than that of the other stoves; the SO2 emission concentration of the gasification reverse burning stove was 1.38 mg ·m-3, which was 28% lower than that of the other stoves. ③ The application technology and combustion type were the main factors affecting the emission levels of the coal stoves. The stove with square briquette technology and gasification reverse burning technology could have great environmental benefit. However, the cost of the two stoves was 20 and 18 thousand yuan, respectively, which was clearly higher than that of the other types of stoves. ④ Considering the difference in the emission of air pollutants from the different stoves, it was suggested to adopt differentiated economic policy and strict emission and product standards, promoting the use of energy-saving and environment-friendly coal stoves to reduce the emission of air pollutants from coal-fired stoves.

Experimental study of bicyclol for type 2 diabetic treatment using KKAy mice / 药学学报

To investigate the effects of small molecule compound bicyclol on type 2 diabetes mellitus (T2DM) and its mechanism of action, KKAy mice were treated with various doses of bicyclol (100, 200, and 400 mg·kg-1·d-1) with metformin (200 mg·kg-1·d-1) as a positive control, respectively. Age-matched C57BL/6J mice were used as the non-diabetic control (Con). The effect on hyperglycemia was evaluated by the levels of no-fasting blood glucose, fasting blood glucose (FPG), and glucose tolerance. Whole body insulin sensitivity was evaluated by fasting plasma insulin (FPI) and homeostasis model assessment-insulin resistance (HOMA-IR). The hepatic response to insulin was evaluated by insulin-induced activation of insulin signaling pathway. Western blot was performed to detect hepatic protein expressions. All animal experimental procedures were approved by the Animal Ethics Committee of Chinese Academy of Medical Sciences. KKAy mice showed T2DM characteristics such as hyperglycemia and insulin resistance, including attenuated response to insulin in the liver. A 28-day treatment of bicyclol suppressed both FPG and no-fasting blood glucose, in a dose- and time-dependent manner. Moreover, FPI and HOMA-IR values were both significantly decreased, and hepatic insulin-induced-phosphorylation of IRβ and Akt were up-regulated in KKAy mice after bicyclol treatment. Phosphorylation of FoxO1, the key transcription factor for regulating gluconeogenesis, was also significantly elevated by bicyclol treatment. These results suggested that bicyclol has some therapeutic effects on hyperglycemia in a time- and dose-dependent manner in KKAy mice. Its mechanism might be attributed to improving insulin resistance, enhancing hepatic insulin signaling pathway, and inhibiting gluconeogenesis. No significant interference on the hypoglycemic effect of metformin by bicyclol was observed in this study.