Heterostructured Co-Doped-Cu2O/Cu Synergistically Promotes Water Dissociation for Improved Electrochemical Nitrate Reduction to Ammonia.

Electrochemical nitrate reduction reaction (NO3RR) has recently emerged as a promising approach for sustainable ammonia synthesis and wastewater treatment, while the activity and selectivity for ammonia production have remained low. Herein, rational design and controllable synthesis of heterostructured Co-doped Cu2O/Cu nanoparticles embedded in carbon framework (Co-Cu2O/Cu@C) is reported for NO3RR. The Co-Cu2O/Cu@C exhibits a high ammonia yield rate of 37.86 mg h-1 mg-1 cat. with 98.1% Faraday efficiency, which is higher than those obtained for most of the Cu-based catalysts under similar conditions. Density functional theory calculations indicated that the strong electronic interactions at Cu/Co-Cu2O interface facilitate the N species deoxygenation process and doping of Co promotes water dissociation to generate *H for the N species hydrogenation process, leading to enhanced NO3RR performance. This work provides a new design strategy toward high-performance catalysts toward NO3RR for ammonia generation.

Spatial scale effects of integrated landscape indicators on river water quality in Chaohu Lake basin, China.

Climate change and rapid urbanization have changed the characteristics of basin landscapes. Non-point-source (NPS) pollution affects river water quality. Exploring the impact of landscapes on river water quality is crucial for the control of water pollution in a basin. Current researchers focus on the impact of landscape pattern change on NPS pollution in the basin, but few consider climate, terrain, soil, and other geographical factors. In this study, we selected a subtropical agricultural basin in China named Chaohu Lake basin as the study area, added precipitation, soil erosion resistance, and slope to the original landscape pattern indicators. We quantified the spatial scale effect and seasonal dependence of integrated landscape indicators on water quality and comprehensively analyzed the optimal spatial scale and key landscape indicators. According to the nonlinear relationship between the key landscape indicators and river nutrients, we also determined the Type-1 threshold values of key landscape indicators for water quality protection in the basin. The results showed that the rivers in Chaohu Lake basin were mainly polluted by nitrogen and phosphorus. The strength of interpretation of the integrated landscape indicators of river water quality increased with riparian zone width. We determined the subbasin scale to be the optimal spatial scale. The key landscape indicators affecting water quality in the wet season at the optimal scale were precipitation and aggregation index of construction land (AIbul), whereas those in the dry season were AIbul and COHESION. The interpretation of the key landscape indicators in the wet season was slightly higher than that in the dry season. The above conclusions provide a scientific reference for NPS pollution control and water quality protection in subtropical agricultural basins.

Interfacially Engineered Nanoporous Cu/MnOx Hybrids for Highly Efficient Electrochemical Ammonia Synthesis via Nitrate Reduction.

Electrochemical reduction of nitrate to ammonia (NH3 ) not only offers a promising strategy for green NH3 synthesis, but also addresses the environmental issues and balances the perturbed nitrogen cycle. However, current electrocatalytic nitrate reduction processes are still inefficient due to the lack of effective electrocatalysts. Here 3D nanoporous Cu/MnOx hybrids are reported as efficient and durable electrocatalysts for nitrate reduction reaction, achieving the NH3 yield rates of 5.53 and 29.3 mg h-1 mgcat. -1 with 98.2% and 86.2% Faradic efficiency in 0.1 m Na2 SO4 solution with 10 and 100 mm KNO3 , respectively, which are higher than those obtained for most of the reported catalysts under similar conditions. Both the experimental results and density functional theory calculations reveal that the interface effect between Cu/MnOx interface could reduce the free energy of rate determining step and suppress the hydrogen evolution reaction, leading to the enhanced catalytic activity and selectivity. This work provides an approach to design advanced materials for NH3 production via electrochemical nitrate reduction.

Quantitative analysis of lake-cooling effect in Hefei City, China, based on multispectral remote sensing and its response to urban expansion.

Urban expansion has intensified the heat-island effect, and the negative impact on the natural environment has gradually become considerable. However, urban lakes can significantly alleviate the heat-island effect caused by urbanization. Based on four-phase multispectral remote-sensing images during 2005-2020, 17 lakes in the main and surrounding urban areas of Hefei, China, were selected as the objects of our research. Each lake's cooling intensity and distance were calculated; cooling-efficiency data for different lakes were compared and analyzed considering lake areas and regional differences. The following conclusions were drawn: (1) The mean temperature of the lake had a strong positive correlation with the cooling-intensity efficiency and the cooling-distance efficiency, and it was the leading influencing factor of the cooling-intensity efficiency and the cooling-distance efficiency. The mean explanation degree was as high as 63.33% and 51.70%, respectively. (2) The lake area and the distance from the lake to the city center had a negative correlation with the cooling-intensity efficiency and cooling-distance efficiency and were the secondary factors that affect the cooling-intensity efficiency and cooling-distance efficiency. (3) The lakes around the urban area were far away from the main urban area where the heat-island effect was most concentrated, the ability of absorbing the high surface temperature caused by the heat-island effect was limited, and the cooling-intensity efficiency and cooling-distance efficiency were reduced by ~ 6.6 °C/km2 and ~ 607.47 m/km2, respectively, compared with the lakes in the main urban area. (4) With urban expansion and the intensified urban heat-island effect, the cooling-intensity efficiency of lakes in the main urban area gradually increased, whereas the cooling-distance efficiency of lakes decreased.

The development of catalysts for electrochemical nitrogen reduction toward ammonia: theoretical and experimental advances.

Ammonia (NH3) is essential for the industrial production of fertilizers, pharmaceuticals, plastics, synthetic fibers, resins, and chemicals, and it is also a promising carbon-free energy carrier. The electrocatalytic nitrogen reduction reaction (eNRR) driven by renewable energy sources at ambient temperature and atmospheric pressure is an alternative approach to the Haber-Bosch process for NH3 synthesis. However, the efficient electrocatalytic reduction of nitrogen (N2) to NH3 is challenging due to the lack of effective electrocatalysts. Tremendous effort has been made to develop high-performance electrocatalysts for the eNRR in the past few years. In this review, we summarize recent progress relating to electrocatalysts for the eNRR from both theoretical and experimental aspects. Remaining challenges and perspectives for promoting the eNRR to generate NH3 are also discussed. This review hopes to guide the design and development of efficient electrocatalysts for the eNRR for NH3 synthesis.

Fraxetin protects rat brains from the cerebral stroke via promoting angiogenesis and activating PI3K/Akt pathway.

OBJECTIVE: Fraxetin has antioxidant, anti-inflammation and neuroprotective functions, however, its role in ischemic stroke is still vague. Herein, this study delves into the underlying mechanism. METHODS: Ischemia and reperfusion operation were performed to establish the cerebral stroke rat models. The brain functions were evaluated with neurological score. The brain infarcted volume in fraxetin group was measured by 2,3,5-triphenyltetrazolium chloride staining. The blood-brain barrier permeability, CD34 enrichment, and the brain water content were measured by Evans blue staining, immunofluorescence staining, and wet-dry method, respectively. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot (WB) were applied to examine the levels of angiogenesis- and PI3K/Akt pathway-related factors. MTT and tube formation assays were used to measure the viability and tube formation of HUVECs. RESULTS: Fraxetin decreased the brain injury-related neurological score, brain infarction, and cerebral edema and maintained blood-brain barrier permeability, whereas it promoted the angiogenesis in ischemia-damaged brain via enhancing CD34 enrichment, the expressions of VEGF, Ang-1, Tie-2, and CD-31, viability of HUVECs, as well as activating the phosphorylation of PI3K and Akt. Importantly, wortmannin (a specific PI3K inhibitor) impeded the fraxetin-induced cell viability, angiogenesis, and phosphorylation of Akt and PI3K in HUVECs. CONCLUSIONS: Fraxetin has protective effects on the brain ischemia-reperfusion injury and promotes angiogenesis for cerebral repair via phosphorylation of PI3K and Akt.

Deep learning-based remote sensing estimation of water transparency in shallow lakes by combining Landsat 8 and Sentinel 2 images.

Water transparency is a key indicator of water quality as it reflects the turbidity and eutrophication in lakes and reservoirs. To carry out remote sensing monitoring of water transparency rapidly and intelligently, deep learning technology was used to construct a new retrieval model, namely, point-centered regression convolutional neural network (PSRCNN) suitable for Sentinel 2 and Landsat 8 images. The impact of input feature variables on the accuracy of the inversion model was examined, and the performance of an optimized PSRCNN model was also assessed. This model was applied to remote sensing images of three shallow lakes in the eastern China plain acquired in summer. The PSRCNN model, constructed using five identical bands from Landsat 8 and Sentinel 2 images and 20 band combinations as the input variables, the input window size of 5 × 5 pixels, proves a good predictive ability, with a verification accuracy of R2 = 0.85, the root mean squared error (RMSE) = 13.0 cm, and the relative predictive deviation (RPD) = 2.58. After the sensitive spectral analysis of water transparency, the band combinations that had correlation coefficients higher than 0.6 were selected as the new input feature variables to construct an optimized PSRCNN model (PSRCNNopt) for water transparency. The PSRCNNopt model has an excellent predictive ability, with a verification accuracy of R2 = 0.89, RMSE = 11.48 cm, and RPD =3.0. It outperforms the commonly retrieval models (band ratios, random forest, support vector machine, etc.), with higher accuracy and robustness. Spatial variations in water transparency of three lakes from the retrieval results by PSRCNNopt model are consistent with the field observations.

Efficient Electrocatalytic Nitrogen Reduction to Ammonia on Ultrafine Sn Nanoparticles.

Electrocatalytic nitrogen reduction reaction (NRR) at ambient conditions is a promising route for ammonia (NH3) synthesis but still suffers from low activity and selectivity. Here, ultrafine Sn nanoparticles (NPs) grown on carbon blacks (SnSC/C) have been synthesized through a wet-chemical method using sodium citrate dehydrate as a stabilizing agent. Benefiting from the small sizes of Sn NPs, the SnSC/C catalyst exhibits excellent electrocatalytic performance for NRR with a high Faradaic efficiency of 22.76% and an NH3 yield rate of 17.28 µg h-1 mg-1 in the 0.1 M Na2SO4 electrolyte, outperforming many reported electrocatalysts for NRR under similar conditions. Density functional theory calculation results reveal that the potential-determining step on Sn NPs is the generation of NHNH* through simultaneous hydrogenation of N2* by a H* and a H+/e- pair via Langmuir-Hinshelwood plus Eley-Rideal mechanisms.

Segmentation Scale Effect Analysis in the Object-Oriented Method of High-Spatial-Resolution Image Classification.

High-spatial-resolution images play an important role in land cover classification, and object-based image analysis (OBIA) presents a good method of processing high-spatial-resolution images. Segmentation, as the most important premise of OBIA, significantly affects the image classification and target recognition results. However, scale selection for image segmentation is difficult and complicated for OBIA. The main challenge in image segmentation is the selection of the optimal segmentation parameters and an algorithm that can effectively extract the image information. This paper presents an approach that can effectively select an optimal segmentation scale based on land object average areas. First, 20 different segmentation scales were used for image segmentation. Next, the classification and regression tree model (CART) was used for image classification based on 20 different segmentation results, where four types of features were calculated and used, including image spectral bands value, texture value, vegetation indices, and spatial feature indices, respectively. WorldView-3 images were used as the experimental data to verify the validity of the proposed method for the selection of the optimal segmentation scale parameter. In order to decide the effect of the segmentation scale on the object area level, the average areas of different land objects were estimated based on the classification results. Experiments based on the multi-scale segmentation scale testify to the validity of the land object's average area-based method for the selection of optimal segmentation scale parameters. The study results indicated that segmentation scales are strongly correlated with an object's average area, and thus, the optimal segmentation scale of every land object can be obtained. In this regard, we conclude that the area-based segmentation scale selection method is suitable to determine optimal segmentation parameters for different land objects. We hope the segmentation scale selection method used in this study can be further extended and used for different image segmentation algorithms.

Interface Engineering of CoP3/Ni2P for Boosting the Wide pH Range Water-Splitting Activity.

Developing electrocatalysts with low price, high energy efficiency, and universal pH value for hydrogen/oxygen evolution reaction (HER and OER) is very important for the wide application of electrochemical water splitting in hydrogen production. The results of density functional theory show that the interface region of CoP3/Ni2P heterostructures can significantly boost all of the catalytic performances. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were used to confirm the abundant structural defects and the corresponding adjustment of the electronic state, thus ameliorating the activation energy, conductivity, and active area of the catalyst. Benefiting from these, CoP3/Ni2P heterostructures exhibit superior performance of both HER and OER in a wide pH range. CoP3/Ni2P can also be used for water splitting (1.557 V at 10 mA cm-2) more than 40 h, superior to benchmark pairs of Pt/C and RuO2 on Ni foam.

Spatial variability of nitrate pollution and its sources in a hilly basin of the Yangtze River based on clustering.

Nitrate (NO3-) pollution is a serious global problem, and the quantitative analysis of its sources contributions is essential for devising effective water-related environmental-protection policies. The Shengjin Lake basin, located in the middle to lower reaches of the Yangtze River in China was selected as the research area in our study. We first grouped 29 surface water samples and 33 groundwater samples using cluster analysis, and then analyzed potential nitrate sources for each dataset of δ15N-NO3- and δ18O-NO3- isotope values by applying a Bayesian isotope-mixing model. Our results show that the nitrogen pollution in the surface-ground water in the study area seriously exceeded to class V of the Environmental Quality Standard of Surface Water of China. The NO3- in surface water from the mid-upper reaches of the drainage basin mainly originates from soil nitrogen (SN) and chemical fertilizer (CF), with contribution rates of 48% and 32%, respectively, and the NO3- in downstream areas mainly originates from CF and manure and sewage (MS), with contribution rates of 48% and 33%, respectively. For the groundwater samples, NO3- mainly originates from MS, CF, and SN in the mid-upper reaches of the drainage basin and the northside of Dadukou near the Yangtze River, with contribution rates of 34%, 31%, and 29%, respectively, whereas NO3- in the lower reaches and the middle part of Dadukou mainly originates from MS, with a contribution rate of 83%. The nitrogen conversion of surface water in lakes and in the mid-upper reaches is mainly affected by water mixing, while the groundwater and surface water in the lower plains are mainly affected by denitrification. The method proposed in this study can expand the ideas for tracking nitrate pollution in areas with complex terrain, and the relevant conclusions can provide a theoretical basis for surface and groundwater pollution control in the hilly basin of Yangtze River.

[Hydro-chemical Characteristics and Ion Origin Analysis of Surface Groundwater at the Shengjin Lake and Yangtze River Interface].

The interface between Shengjin Lake and Yangtze River was selected as the study area. The water chemical composition and hydrogen and oxygen isotope values of different types of water bodies were tested, and their seasonal variation characteristics were analyzed to explore the sources of chemical ions in the surface and groundwater. Finally, the contribution of mixed water sources to chemical ions in groundwater was estimated. The results show the following ① The concentration of chemical ions in the surface and groundwater of the study area is higher than that of atmospheric precipitation, and the physical and chemical parameters exhibit seasonal variation. ② Surface water mainly belongs to the Ca-HCO3 type, but the proportion of the Ca-SO4 type in summer is significantly lower than that in other seasons; Groundwater primarily belongs to Ca-HCO3 and Ca-SO4 types, with proportions of 46% and 27%, respectively, and the seasonal difference is not significant. ③ Ca2+ and Mg2+ in the surface and groundwater mainly come from the dissolution of carbonate rocks, carbonic acid and sulfate ions participate in the dissolving process of carbonate minerals. Na+and Cl- are partly derived from atmospheric precipitation and partly sourced from agricultural fertilization and manure sewage. ④ Mixed water sources is also an important source of chemical ions in groundwater, with the average contribution 28% to Cl-, showing a seasonal trend.

Land use and land cover change detection and spatial distribution on the Tibetan Plateau.

Regarded as the third pole of the Earth, the Tibetan Plateau (TP) is a region with complex terrain. Vegetation is widely distributed in the southeastern part of the plateau. However, the land use and land cover changes (LULCC) on the TP have not been sufficiently studied. In this study, we propose a method of studying the dynamic changes in the land cover on the TP. Landsat OLI images (2013 and 2015) were selected to extract the LULCC information of Nyingchi County, the DEM was used to extract objects' land curved surface area and analyze their three-dimensional dynamic change information, which realized a four-dimensional monitoring of the forestry information on time and spatial level. The results showed that the forest area in 2015 decreased by 7.25%, of which the coniferous forest areas decreased by 25.14%, broad-leaved forest areas increased by 12.65%, and shrubbery areas increased by 14.62%. Compared with traditional LULCC detection methods, the change detection is no longer focused on the two-dimensional space, which helps determine the three-dimensional land use and land cover changes and their distribution. Thus, dynamic spatial changes can be observed. This study provides scientific support for the vegetation restoration and natural resource management on the TP.

Consistency of Suspended Particulate Matter Concentration in Turbid Water Retrieved from Sentinel-2 MSI and Landsat-8 OLI Sensors.

Research on the consistency of suspended particulate matter (SPM) concentration retrieved from multisource satellite sensors can serve as long-time monitoring of water quality. To explore the influence of the atmospheric correction (AC) algorithm and the retrieval model on the consistency of the SPM concentration values, Landsat 8 Operational Land Imager (OLI) and Sentinel 2 MultiSpectral Imager (MSI) images acquired on the same day are used to compare the remote sensing reflectance (Rrs) SPM retrieval values in two high-turbidity lakes. An SPM retrieval model for Shengjin Lake is established based on field measurements and applied to OLI and MSI images: two SPM concentration products are highly consistent (R2 = 0.93, Root Mean Squared Error (RMSE) = 20.67 mg/L, Mean Absolute Percentage Error (MAPE) = 6.59%), and the desired results are also obtained in Chaohu Lake. Among the four AC algorithms (Management Unit of the North Seas Mathematical Models (MUMM), Atmospheric Correction for OLI'lite'(ACOLITE), Second Simulation of Satellite Signal in the Solar Spectrum (6S), Landsat 8 Surface Reflectance Code & Sen2cor (LaSRC & Sen2cor)), the two Rrs products, as well as the final SPM concentration products retrieved from OLI and MSI images, have the best consistency when using the MUMM algorithm in SeaWIFS Data Analyst System (SeaDAS) software. The consistency of SPM concentration values retrieved from OLI and MSI images using the same model or same form of models is significantly better than that retrieved by applying the optimal models with different forms.

A classifier-combined method based on D-S evidence theory for the land cover classification of the Tibetan Plateau.

The Tibetan Plateau (TP) is a region with high altitudes and complicated terrain conditions. Due to the special conditions of this region, it is also regarded as the third pole of the Earth. The land cover and vegetation in this region have not been extensively studied, so this study investigated the possibility of using a combined classifier that was established based on D-S evidence theory to extract the land cover of the TP. Multiple feature images were obtained based on a single classification rule, and the feature images were normalized to obtain the basic probability assignment (BPA). The BPA was used as the evidence source to represent the belief level of each type of land cover. The information for the different belief levels was combined based on the D-S evidence theory. The maximum belief level of the combination results was used to identify the land cover types on the TP. The results of this study indicate that based on the D-S evidence theory, multiple classifiers can effectively be combined to improve the classification results. This study has also revealed that more classifiers fused together to make a combined classifier did not result in the combined classifier's accuracy being higher than those of the original classifiers. Higher accuracies were only obtained when more high accuracy evidence theory was used in the classifier combination, in which case, the combined classifier's classification accuracy was also high.

[Remote Sensing Monitoring on Spatial Differentiation of Suspended Sediment Concentration in a River-Lake System Based on Sentinel-2 MSI Imaging:A Case for Shengjin Lake and Connected Yangtze River Section in Anhui Province].

Carrying out monitoring of suspended sediment concentration in river and lake systems is of great significance for understanding the laws of sediment transport in water and formulating policies on water environmental control. Taking Shengjin Lake and the connected Yangtze river section in Anhui province as the study area, band reflectance of a Sentinel-2 MSI sensor is simulated according to field spectral datasets, and the retrieval model is established by statistical regression from the synchronized suspended sediment concentration measurements. Then, the retrieved results from 28 scene MSI images during 2017-2019 are used to analyze the spatiotemporal variation of suspended sediment concentration in rivers and lakes, and the influence of water level variation on their spatial differentiation is also discussed. The results show that:① The retrieval model established by the ratio of the sixth band to the third band of the MSI sensor is suitable for high-turbidity water type, with high accuracy (R2=0.863, RMSE=22.211 mg·L-1). ② Spatially, the suspended sediment concentration near the lake entrances, northwestern parts of the upper and middle lake areas, and the lower lake is relatively higher, and that of Shengjin Lake is lower than that of the Yangtze River overall except for in summer. Temporally, the suspended sediment concentration in Shengjin Lake is relatively lower in summer and higher in other seasons, while the connected Yangtze River section exhibits the opposite intra-annual variation. ③ The water level, which is caused by the connectivity of rivers and lakes under the influence of the sluice, is the key factor affecting the spatial differentiation of suspended sediment concentration in the river and lake system. The suspended sediment concentration in Shengjin Lake contributes to the Yangtze River in dry and normal water periods, and that in the normal water period is more significant. In contrast, during the flood period, the correlation between suspended sediment concentration in the Yangtze River and that in Shengjin Lake is not obvious.

Correction to: Study on habitat suitability of overwintering cranes based on landscape pattern change-a case study of typical lake wetlands in the middle and lower reaches of the Yangtze River.

The correct corresponding Author of this paper is Bin Dong.

Vitexin protects against ischemia/reperfusion-induced brain endothelial permeability.

Brain endothelial permeability plays a crucial role in blood-brain barrier (BBB), but the permeability enhancement in cerebral ischemia reperfusion (I/R). Vitexin has certain neuroprotective effects, but the effect brain endothelial permeability in I/R injury was unknown. In this study, the effects of Vitexin on endothelial permeability and the underlying mechanisms in human brain microvascular endothelial cells (HBMEc) I/R injury model were investigated. Cell viability, lactate dehydrogenase (LDH), inflammation and apoptosis were detected. The effects of Vitexin on BBB integrity tight junction, matrix metalloproteinases (MMP) were also investigated. The mechanism was confirmed by PI3K inhibitor and NOS inhibitor in normal or eNOS siRNA transfection HBMEc. Vitexin significantly reduced LDH, Caspase 3 level, alleviated inflammation, also could maintain BBB integrity, increased tight junction proteins expression and inhibited MMP. The mechanism is related to reduction of intracellular NO and ONOO-, regulated eNOS, iNOS activity. Vitexin significantly preserved eNOS phosphorylation in response to the activated Akt. Moreover, combined with PI3K inhibitor or low dosage of NOS inhibitor, totally abolished Vitexin-induced eNOS phosphorylation, the protected effect was also attenuated, but still significantly between model cells. However, combined with high dosage NOS inhibitor which both inhibited the eNOS phosphorylation and iNOS, the protected effect of Vitexin was abrogated. In addition, eNOS silencing cells were used to further clarify the regulatory role of Vitexin on iNOS. Our findings showed that Vitexin could play a protective role in I/R-induced brain endothelial permeability by simultaneously increase eNOS phosphorylation and inhibit iNOS.

Study on habitat suitability of overwintering cranes based on landscape pattern change-a case study of typical lake wetlands in the middle and lower reaches of the Yangtze River.

Shengjin Lake wetland is located in the middle and lower reaches of the Yangtze River in China. It is a typical lake-type wetland and is also an ideal place for rare cranes to overwintering. The changes of wetland landscape are closely related to the habitat quality of wintering cranes. It is of great significance to study the habitat change of wintering cranes in wetland for wetland ecological restoration and restoration. In this paper, we analyze four kinds of winter cranes and wetland landscape pattern types from the years 1986 to 2015. Also, we adopted the Pearson correlation analysis method to analyze the relationship between wetland landscape types and crane population, and the main landscape types of cranes habitat were obtained. We selected disturbance degree, food richness, vegetation cover, and hydrological condition as the main factors affecting wintering habitat of cranes. We established a habitat suitability index model for wintering cranes and generated habitat suitability assessment maps by ArcGIS. The results show that the change of landscape pattern in Shengjin Lake protected area was obvious, the number of wetland patches increased, the fragmentation degree of landscape increased, the landscape patch difference became smaller, and the diversity index and evenness index increased gradually. From 1986 to 2015, the number of wintering cranes decreased and the habitat suitability index of wintering cranes decreased from 0.845 to 0.465, and the habitat suitability of wintering cranes fell from 13,577.11 to 7424.42 ha, which showed the overall habitat deteriorated significantly and had a positive correlation between the crane population and habitat suitability.

[Effects of butylphthalide on the apoptosis of PC-12 cells under the induction of ß-amyloid peptide].

OBJECTIVE: To study the protective effects of butylphthalide (NBP) on the Aß(25-35)-induced apoptosis in PC-12 cells. METHODS: The apoptosis of PC-12 cell was analyzed by MTT assay, transmission electron microscope and PI method at different concentrations of NBP (0.1, 1.0, 10, 100 µmol/L) with the addition of Aß or not. The expressions of Bcl-2 and cytochrome C (Cyt-C) were detected by Western blot. RESULTS: As demonstrated by the MTT assay, the values of cell viability were 76.5% ± 1.1%, 84.2% ± 1.3%, 89.5% ± 1.3% and 81.9% ± 1.9% at various concentration (0.1, 1.0, 10, 100 µmol/L) of NBP respectively. The model group was 71.7% ± 1.4%. It was revealed that the former could significantly prevent the cell viability under the induction of Aß(25-35) (P < 0.05). A pretreatment with 10 µmol/L NBP could significantly inhibit the decrease of viability under the induction of Aß(25-35) (P < 0.05). PI showed that the apoptosis rate of the 10 µmol/L NBP treatment group was significantly lower than that of the model group. Under electron microscope, the characteristics of cell apoptosis were significant in the model group. And the cell morphology of the 10 µmol/L NBP treatment group was normal. The expression rate of Bcl-2 protein in the 10 µmol/L NBP treatment group was obviously higher than that in the model group. Cyt-C was weakly expressed in nerve cells of the normal and the 10 µmol/L NBP groups. But it had a strong expression in the model group. CONCLUSION: NBP prevents the injury of PC12 cells by Aß. And the mechanism may be related to the elevated level of Bcl-2 and the inhibited mitochondrial release of Cyt-C.