Remote sensing identification of urban water pollution source types using hyperspectral data.

Owing to accelerated urbanisation, increased pollutants have degraded urban water quality. Timely identification and control of pollution sources enable relevant departments to effectively perform water treatment and restoration. To achieve this goal, a remote sensing identification method for urban water pollution sources applicable to unmanned aerial vehicle (UAV) hyperspectral images was established. First, seven fluorescent components were obtained through three-dimensional excitation-emission matrix fluorescence spectroscopy of dissolved organic matter (DOM) combined with parallel factor analysis. Based on the hierarchical cluster analysis of the seven fluorescence components and three spectral indices, four pollution source (PS) types were determined, namely, domestic sewage, terrestrial input, agricultural and algal, and industrial wastewater sources. Second, several water colour and optical parameters, including the absorption coefficient of chromophoric DOM at 254 nm, humification index, chlorophyll-a concentration, and hue angle, were utilised to develop an identification method with a recognition accuracy exceeding 70% for the four PSs that is suitable for UAV hyperspectral data. This study demonstrated the potential of identifying PSs by combining the fluorescence characteristics of DOM with the optical properties of water, thus expanding the application of remote sensing technologies and providing more comprehensive and reliable information for urban water quality management.

Contributions of meteorology and nutrient to the surface cyanobacterial blooms at different timescales in the shallow eutrophic Lake Taihu.

Quantitative assessments of the contributions of various environmental factors to cyanobacterial blooms at different timescales are lacking. Here, the hourly cyanobacterial bloom intensity (CBI) index, a proxy for the intensity of surface cyanobacterial biomass, was obtained from the geostationary satellite sensor Geostationary Ocean Color Imager (GOCI) over the years 2011-2018. Generalized additive model was applied to determine the responses of monthly and hourly CBI to the perturbations of meteorological factors, water stability and nutrients, with variation partitioning analysis used to analyze the relative importance of the three groups of variables to the inter-monthly variation of diurnal CBI in each season. The effects of environmental factors on surface cyanobacterial blooms varied at different timescales. Hourly CBI increased with increasing air temperature up to 18 °C but decreased sharply above 18 °C, whereas monthly CBI increased with increasing air temperature up to 30 °C and stabilized thereafter. Among all the environmental factors, air temperature had the largest contribution to the intra-daily variation in CBI; water stability had the highest explanation rate for the inter-monthly variation of diurnal CBI during summer (42.3 %) and autumn (56.9 %); total phosphorus explained the most variation in monthly CBI (18.5 %). Compared with cyanobacterial biomass (CB) in the water column, high light and low wind speed caused significantly lower CBI in July and higher CBI in November respectively. Interestingly, cyanobacterial blooms at the hourly scale were aggravated by climate warming during winter and spring but inhibited during summer and autumn. Collectively, this study reveals the effects of environmental factors on surface cyanobacterial blooms at different timescales and suggests the consideration of the hourly effect of air temperature in short-term predictions of cyanobacterial blooms.

A hybrid remote sensing approach for estimating chemical oxygen demand concentration in optically complex waters: A case study in inland lake waters in eastern China.

Chemical oxygen demand concentration (CCOD) is widely used to indicate the degree of organic pollution of lakes, reservoirs and rivers. Mastering the spatiotemporal distribution of CCOD is imperative for understanding the variation mechanism and controlling of organic pollution in water. In this study, a hybrid approach suitable for Sentinel 3A/Ocean and Land Colour Instrument (OLCI) data was developed to estimate CCOD in inland optically complex waters embedding the interaction between CCOD and the absorption coefficients of optically active constituents (OACs). Based on in-situ sampling in different waters, the independent validations of the proposed model performed satisfactorily in Lake Taihu (MAPE = 23.52 %, RMSE = 0.95 mg/L, and R2 = 0.81), Lake Qiandaohu (MAPE = 21.63 %, RMSE = 0.50 mg/L and R2 = 0.69), and Yangtze River (MAPE = 29.34 %, RMSE = 0.83 mg/L, and R2 = 0.64). In addition, the approach not only showed significant superiority compared with previous algorithms, but also was suitable for other common satellite sensors equipped same or similar bands. The hybrid approach was applied to OLCI images to retrieve CCOD of Lake Taihu from 2016 to 2020 and reveals substantial interannual and seasonal variations. The above results indicate that the proposed approach is effective and stable for studying spatiotemporal dynamic of CCOD in optically complex waters, and that satellite-derived products can provide reliable information for lake water quality management.

Long-term monitoring particulate composition change in the Great Lakes using MODIS data.

Particulate composition provides important information for understanding the changes in underwater light fields and primary productivity. In this study, a semianalytical algorithm, based on Rayleigh-corrected reflectance at 678 nm and 748 nm on Moderate Resolution Imaging Spectroradiometer (MODIS) images was used to estimate the ratio of chlorophyll a to total suspended solids (Chla/TSS), which characterizes the particulate composition of the Great Lakes. The long-term spatial and temporal characteristics of Chla/TSS in the Great Lakes from 2000 to 2020 were obtained. The results demonstrated that Lake Superior had the highest average Chla/TSS values (5.79±0.76 µg/mg), while Lake Erie had the lowest average Chla/TSS values (2.93±0.76 µg/mg). The Mann-Kendall test showed that the Chla/TSS of the Great Lakes all showed an increasing trend, notably in Lake Michigan, with 88.23% pixels showing significant increasing trend. Climatic and hydrological factors dominated the intra-annual variation of Chla/TSS, with contribution rates ranging from 71.47% to 92.54%. Through the annual Chla/TSS change pattern analysis, it was found that the contribution of wind speed to the annual variation in Chla/TSS was slight. Changes in temperature played a major role in the interannual variability of Chla/TSS in Lake Superior and Ontario; runoff and settlement were the major contributors in Lake Huron and Michigan, while cropland dominated the Chla/TSS interannual variability in Lake Erie. Furthermore, the significantly low values of Chla/TSS in spring had the potential to predict the occurrence of blooms in western Lake Erie, and the spatial distribution of Chla/TSS could help predict the location of blooms in the next few days.

Analysis and Countermeasures of related factors of mental health and physical exercise of College Students

This paper examines the relationship between college students' mental health and physical exercise, analyzes the beneficial effect of physical exercise on mental health, enhances school physical education and health education, and provides a theoretical foundation for further enhancing college students' mental health. The SCL-90 was used to evaluate "the last week's" mental health condition. There are 90 possibilities on the scale, comprising 10 factors (depression, hostility, psychosis, somatization, anxiety, obsessive-compulsive symptoms, paranoia, terror, interpersonal sensitivity and others). 93% of students in certain colleges have a positive psychological experience of participating in physical activity. According to the t-test, the mental health level of college students who regularly participate in physical activity is much better than that of college students who occasionally and never participate in physical activity (P <0.01). The impact of physical activity on the mental health of college students of different genders varies. Exercise significantly improves college students' mental health; factors such as duration of physical activity, frequency of exercise, and variety of sports significantly impact mental health development.(AU)

Monitoring the particulate phosphorus concentration of inland waters on the Yangtze Plain and understanding its relationship with driving factors based on OLCI data.

Tracking the spatiotemporal dynamics of particulate phosphorus concentration (CPP) and understanding its regulating factors is essential to improve our understanding of its impact on inland water eutrophication. However, few studies have assessed this in eutrophic inland lakes, owing to a lack of suitable bio-optical algorithms allowing the use of remote sensing data. Herein, a novel semi-analytical algorithm of CPP was developed to estimate CPP in lakes on the Yangtze Plain, China. The independent validations of the proposed algorithm showed a satisfying performance with the mean absolute percentage error and root mean square error less than 27% and 27 µg/L, respectively. The Ocean and Land Color Instrument observations revealed a remarkable spatiotemporal heterogeneity of CPP in 23 lakes on the Yangtze Plain from 2016 to 2020, with the lowest value in December (62.91 ± 34.59 µg/L) and the highest CPP in August (114.9 ± 51.69 µg/L). Among the 23 examined lakes, the highest mean CPP was found in Lake Poyang (124.58 ± 44.71 µg/L), while the lowest value was found in Lake Qiandao (33.51 ± 4.71 µg/L). Additionally, 13 lakes demonstrated significant decreasing or increasing trends (P < 0.05) of annual mean CPP during the observation period. The driving factor analysis revealed that four natural factors (wind speed, air temperature, precipitation, and sunshine duration) and two anthropogenic factors (the normalized difference vegetation index and nighttime light) combined explained more than 91% of the variation in CPP, while the impacts of these factors on CPP showed considerable differences among lakes. This study offered a novel and scalable algorithm for the study of the spatiotemporal variation of CPP in inland waters and provided new insights into the regulating factors in water eutrophication.

Preliminary research on total nitrogen content prediction of sandalwood using the error-in-variable models based on digital image processing.

This paper presents a method for predicting the total nitrogen content in sandalwood using digital image processing. The goal of this study is to provide a real-time, efficient, and highly automated nutritional diagnosis system for producers by analyzing images obtained in forests. Using images acquired from field servers, which were installed in six forest farms of different cities located in northern Hainan Province, we propose a new segmentation algorithm and define a new indicator named "growth status" (GS), which includes two varieties: GSMER (the ratio of sandalwood pixels to the minimum enclosing rectangle pixels) and GSMCC (the ratio of sandalwood pixels to minimum circumscribed circle pixels). We used the error-in-variable model by considering the errors that exist in independent variables. After comparison and analysis, the obtained results show that (1) The b and L channels in the Lab color system have complementary advantages. By combining this system with the Otsu method, median filtering and a morphological operation, sandalwood can be separated from the background. (2) The fitting degree of the models improves after adding the GS indicator and shows that GSMCC performs better than GSMER. (3) After using the error-in-variable model to estimate the parameters, the accuracy and precision of the model improved compared to the results obtained using the least squares method. The optimal model for predicting the total nitrogen content is [Formula: see text]. This study demonstrates the use of Internet of Things technology in forestry and provides guidance for the nutritional diagnosis of the important sandalwood tree species.

Different responses of galanin and calcitonin gene-related peptide to capsaicin stimulation on dorsal root ganglion neurons in vitro.

Both galanin (Gal) and calcitonin gene-related peptide (CGRP) are sensory neuropeptides which expressed in dorsal root ganglion (DRG) neurons and are involved in nociceptive processing. Capsaicin (CAP) influences nociceptive processing via influencing the expression of sensory neuropeptides in primary sensory neurons. However, little is known about the alterations of Gal and CGRP expression at the same condition stimulated by CAP. In the present study, primary cultured DRG neurons were used to determine the different responses of Gal and CGRP to CAP stimulation. DRG neurons were cultured for 48 hours and then exposed to CAP (2 µmol/L), capsazepine (CPZ) (2 µmol/L) plus CAP (2 µmol/L), or extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor PD98059 (10 µmol/L) plus CAP (2 µmol/L) for an additional 24hours. The DRG neurons were continuously exposed to culture media as a control. After that, the levels of Gal mRNA and CGRP mRNA of DRG neurons were determined using real time-PCR analysis. Gal and CGRP expression in situ was detected by an immunofluorescent labeling technique. The levels of phosphorylated-ERK1/2 (pERK1/2) protein were detected using a Western blot assay. The results showed that CAP evoked increases of Gal and its mRNA and decreases of CGRP and its mRNA in DRG neurons. Administration of either CPZ or PD98059 blocked the effects of CAP. These data indicate that Gal and CGRP shared different responses to CAP stimulation. Gal and CGRP may have different effects in nociceptive processing during neurogenic inflammation.

Formation of neuromuscular junction-like structure between primary sensory terminals and skeletal muscle cells in vitro.

Sensory nerve cross-anastomosis provides a modified trophic environment by modulating neurotrophic factor synthesis in muscle. Target tissues contribute to the phenotype and function of sensory neurons. Whether formation of neuromuscular junction (NMJ)-like structure between sensory neurons and skeletal muscle (SKM) cells in vitro remains unknown. In this study, a neuromuscular coculture model of dissociated dorsal root ganglion (DRG) neurons and SKM cells was established. The relationship between DRG neurons and SKM cells was observed by light microscopy and scanning electron microscopy (SEM). The results showed that: (1) DRG neuronal axons frequently terminated on or adhered to the SKM cells; (2) the crossing axons adhered to each other, hence displacement of the terminal axons on the contracting SKM cells would also oscillate the proximally crossing axonal network; (3) the configurations of the axon terminal observed by SEM were variable in different culture conditions; (4) the enlarged nerve endings terminated on the surface of SKM cells which formed NMJ-like structure. These results offered new clues for a better understanding of the relationship between sensory neurons and SKM cells.

Nerve growth factor regulates galanin and neuropeptide Y expression in primary cultured superior cervical ganglion neurons.

Both galanin and neuropeptide Y (NPY) are expressed in superior cervical ganglion (SCG) neurons. Following nerve transection or axotomy galanin is strongly upregulated and NPY is downregulated in SCG neurons because target-derived nerve growth factor (NGF) content decreased. It is not known whether or to what extent NGF affects both galanin and NPY expression in primary cultured SCG neurons. In the present study we examine whether exogenous NGF affects expression of neuropeptides for galanin and NPY in primary cultured SCG neurons. In addition, we explore whether mRNAs for galanin and NPY are affected by administration of exogenous NGF in SCG cultures. The significance of expression of galanin and NPY and their mRNAs was revealed by performing experiments without and with administration of exogenous NGF. Galanin and its mRNA expression was attenuated by administration of exogenous NGF in SCG cultures. The enhancement of NPY and its mRNA expression by administration of exogenous NGF in SCG cultures was dose-dependent. The physiological or pathophysiological mechanisms of the alterations of galanin and NPY expression affected by NGF in primary cultured SCG neurons are still unknown. The present data provide basic knowledge about the expression of galanin and NPY in primary cultured SCG neurons of rats, which may further improve our understanding of the functional significance of galanin and NPY expression affected by NGF.

Regulatory effects of insulin-like growth factor-1 on the expression of sensory neuropeptide mRNAs in cultured dorsal root ganglion neurons with excitotoxicity induced by glutamate.

OBJECTIVE: To determine the effects of insulin-like growth factor-1 (IGF-1) on the expression of preprotachykinin (PPT) mRNA encoding substance P (SP) and calcitonin gene-related peptide (CGRP) mRNA in cultured dorsal root ganglion (DRG) neurons with excitotoxicity induced by glutamate (Glu). METHODS: DRGs were dissected from embryonic day 15 Wistar rats. DRG neurons were dissociated and cultured for 48 h and then exposed to Glu (0.2 mmol/L) or Glu (0.2 mmol/L) plus IGF-1 (5 nmol/L, 10 nmol/L and 20 nmol/L) for 12 h. The DRG neurons in control group were exposed to only growth media throughout the experiment. After that, the living DRG neurons were observed under inverted phase contrast microscope and microphotographs were taken. The expression levels of PPT and CGRP mRNAs were detected by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: IGF-1 could inhibit Glu-induced shortening of neurite. Besides, IGF-1 could significantly increase the levels of PPT mRNA and CGRP mRNA in primary cultured DRG neurons with Glu-induced excitotoxicity, in a dose-dependent manner. CONCLUSION: IGF-1 may exert neuroprotective effects on DRG neurons against Glu-induced excitotoxicity, probably through regulating the expression levels of PPT and CGRP mRNAs.

Insulin-like growth factor-1 modulates Ca2+ homeostasis and apoptosis of cultured dorsal root ganglion neurons with excitotoxicity induced by glutamate.

Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor and a potent anti-apoptotic factor. IGF-1 plays an important role in promoting axonal growth from dorsal root ganglion (DRG) neurons and prevents apoptosis in DRG neurons. Whether IGF-1 could modulate Ca2+ homeostasis and apoptosis of sensory DRG neurons with excitotoxicity induced by glutamate (Glu) is still unknown. In the present study, primary cultured DRG neurons were used to determine the effects of IGF-1 on Ca2+ homeostasis and apoptosis of sensory DRG neurons with excitotoxicity induced by Glu. Intracellular Ca2+ concentration ([Ca2+]i) in isolated DRG neurons using the fluorescent Ca2+ indicator fura-3 was measured by confocal laser scanning microscope (CLSM). Procaspase-3 expression was detected by Western blot analysis. Application of 0.2 mmol/L Glu evoked an increase in [Ca2+]i, confirming the excitatory effect of Glu at this stage. The decrease of procaspase-3 expression levels after application of 0.2 mmol/L Glu suggested the apoptotic effects of Glu. These effects could be inhibited by the presence of IGF-1. In conclusion, we demonstrated that IGF-1 could modulate Ca2+ homeostasis and apoptosis of sensory DRG neurons with excitotoxicity induced by Glu. Both Ca2+ homeostasis and caspase-3 processing were implicated as the underlying neuroprotective mechanisms of IGF-1.

Co-administration of monosialoganglioside and skeletal muscle cells on dorsal root ganglion neuronal phenotypes in vitro.

The neuropeptide-immunoreactive (IR) and neurofilament-IR neurons are two major phenotypical classes in dorsal root ganglion (DRG). Targets of neuronal innervation play a vital role in regulating the survival and differentiation of innervating neurotrophin-responsive neurons. Monosialoganglioside (GM1) has been considered to have a neurotrophic factor-like activity. Both GM1 and target skeletal muscle (SKM) cells are essential for the maintenance of the function of neurons. However, whether target SKM cells and GM1, alone or associated, generate neuropeptide or neurofilament expression remains unclear. The aim of the present study is to investigate the effects of GM1 or/and SKM on DRG neuronal phenotypes. DRG neurons containing the neuropeptide substance P (SP) and neurofilament 200 (NF-200) were quantified using immunofluorescent labeling in cultures of DRG, which was dissected out at times before (at embryonic days 12.5, E12.5) and after (at E19.5) sensory neurons contact peripheral targets in vivo. DRG neurons were cultured in absence or presence of GM1 or/and SKM cells. In this experiment, we found that: (1) GM1 promoted expression of SP and NF-200 in E12.5 DRG cultures; (2) SKM cells promoted expression of NF-200 but not SP in E12.5 DRG cultures; (3) GM1 and target SKM cells had additive effects on expression of SP and NF-200 in E12.5 DRG cultures; and (4) SKM or/and GM1 did not have effects on expression of SP and NF-200 in E19.5 DRG cultures. These results suggested that GM1 could influence DRG, two major neuronal phenotypes, before sensory neurons contact peripheral targets in vivo. Target SKM cells could only influence neurofilament-expressed neuronal phenotype before sensory neurons contact peripheral targets in vivo. GM1 and SKM cells had the additive effects on two major DRG neuronal classes, which express neuropeptide or neurofilament when DRG cells were harvested before sensory neurons contact peripheral targets in vivo. These results offered new clues for a better understanding of the association of GM1 or/and SKM with neuronal phenotypes.

Neuronal phenotype and tyrosine kinase receptor expression in cocultures of dorsal root ganglion and skeletal muscle cells.

The neuropeptide-immunoreactive (IR) and neurofilament-IR neurons are two major phenotypical classes in dorsal root ganglion (DRG). Tyrosine kinase receptor (Trk)A, TrkB, and TrkC are three members of the Trk family which may be relevant to neuronal phenotypes. Whether target skeletal muscle cells generate their expression remains unclear. Neurons containing substance P (SP), calcitonin gene-related peptide (CGRP), neurofilament 200 (NF-200), TrkA, TrkB, and TrkC were quantified using immunohistochemistry in rat DRG neuronal cultures and cocultures of DRG neurons and skeletal muscle cells. The percentage of NF-200 and TrkC-expressing neurons in cocultures of DRG neurons and skeletal muscle cells was significantly higher, 26.86% +/- 3.17% (NF-200) and 27.74% +/- 3.63% (TrkC) compared with 20.92% +/- 1.98% (NF-200) and 16.70% +/- 3.68% (TrkC) in DRG cultures; whereas the percentage of SP, CGRP, TrkA, and TrkB-expressing neurons was not changed significantly by the addition of target skeletal muscle cells. Thus, target skeletal muscle cells may influence neurofilament-phenotype and TrkC receptor but not neuropeptide-phenotype and TrkA and TrkB receptors. Anat Rec, 2009. (c) 2008 Wiley-Liss, Inc.

Exogenous galanin regulates capsaicin-evoked substance P release from primary cultured dorsal root ganglion neurons.

OBJECTIVES: To determine the effect of exogenous galanin on capsaicin-evoked substance P (SP) release from primary cultured embryonic rat dorsal root ganglion (DRG) neurons. METHODS: DRG was dissected out from embryonic 15-day-old Wistar rat and cultured as dissociated cells for 2 days then exposed to galanin (1 nmol/L, 10 nmol/L, 100 nmol/L). After 4 days incubation with exogenous galanin, the levels of mRNAs for SP and vanilloid receptor 1 (VR1) and protein for VR1 were estimated by RT-PCR and Western blot, respectively. Basal SP release and capsaicin-evoked SP release levels were measured by radioimmunoassay (RIA). RESULTS: The amount of VR1 mRNA and VR1 protein expression and capsaicin-evoked SP release in cultured DRG neurons increased significantly after incubation with exogenous galanin compared with control DRG neurons at the same time point, whereas the amount of SP mRNA and basal SP release were not affected after incubation with exogenous galanin. DISCUSSION: Exogenous galanin may promote capsaicin-evoked SP release from primary cultured DRG neurons. The elevation of the levels of VR1 mRNA and VR1 protein induced by exogenous galanin implicated that VR1 may be involved in the mechanisms of SP release evoked by capsaicin.

GM1 and NGF modulate Ca2+ homeostasis and GAP43 mRNA expression in cultured dorsal root ganglion neurons with excitotoxicity induced by glutamate.

Monosialoganglioside (GM1) has been considered to have a neurotrophic factor-like activity. Nerve growth factor (NGF), a member of the neurotrophin family, is essential for neuronal survival, differentiation and maturation. The aim of the present study was to investigate whether co-administration of GM1 and NGF reverses glutamate (Glu) neurotoxicity in primary cultured rat embryonic dorsal root ganglion (DRG) neurons. DRG neurons were exposed to Glu (2 mmol/1), Glu (2 mmol/1) plus GM1 (10 microg/ml), Glu (2 mmol/l) plus NGF (10 ng/ml), Glu (2 mmol/l) plus GM1 (5 microg/ml) and NGF (5 ng/ml) and then processed for detecting intracellular concentrations of Ca2+ ([Ca2+] i) by confocal laser scanning microscopy and growth-associated protein 43 (GAP43) mRNA by RT-PCR. The fluorescent intensity in Glu plus GM1 and NGF incubated neurons was the lowest as compared with that in other groups. The expression of GAP43 mRNA in Glu plus GM1 and NGF incubated neurons was the highest as compared with that in other groups. These results implicated that GM1 and NGF have synergistic neuroprotective effects on DRG neurons with excitotoxicity induced by Glu in vitro.

Pioglitazone inhibits hypertrophy induced by high glucose and insulin in cultured neonatal rat cardiomyocytes.

The aim of the present study was to determine whether the antidiabetic agent pioglitazone has a direct inhibiting effect on myocardial hypertrophy induced by high glucose and insulin in primary cultured neonatal rat cardiomyocytes. Culture preparations of ventricular muscle cells newborn rats were utilized. At 72 h of culture age, the cardiomyocytes were incubated for another 48 h with 25.5 mmol/L glucose plus 0.1 micromol/L insulin (group 2), 25.5 mmol/L glucose and 0.1 micromol/L insulin plus 10 micromol/L pioglitazone (group 3), 10 micromol norepinephrine (group 4), respectively. Cells cultured continuously in medium served as control (group 1). Cellular surface area, protein content, atrial natriuretic factor (ANF) mRNA, and cardiotrophin-1 (CT-1) mRNA were assessed after treatment with different agents. All those parameters increased significantly after treatment with high glucose and insulin as compared with control (P < 0.01). These effects were inhibited markedly by pioglitazone. The cellular surface area and ANF mRNA in group 3 were decreased as compared with group 2 (P < 0.01). The protein content and CT-1 mRNA in group 3 were also decreased as compared with group 2 (P < 0.05). We concluded that a the cellular level myocardial hypertrophy induced by high glucose and insulin was inhibited directly by pioglitazone in primary cultured cardiac myocytes. CT-1 may be involved in myocardial hypertrophy induced by high glucose andinsulin and inhibiting effects of pioglitazone on myocardial hypertrophy.

Butyrate sensitizes the release of substance P and calcitonin gene-related peptide evoked by capsaicin from primary cultured rat dorsal root ganglion neurons.

OBJECTIVES: To investigate whether butyrate increases substance P (SP) and calcitonin gene-related peptide (CGRP) release evoked by capsaicin from primary cultured dorsal root ganglion (DRG) neurons. METHODS: DRG was dissected out from embryonic 15-day-old Wistar rat and cultured as dissociate cells for 24 h then exposed to butyrate (0.01 mmol/L, 0.1 mmol/L, 1 mmol/L, 10 mmol/L, respectively) for another 48 h. The neurons cultured continuously in media served as normal control. All above cultured samples were processed for detecting expression of mRNA for SP, CGRP and vanilloid receptor 1 (VR1) of DRG neurons by RT-PCR, and VR1 protein expression by Western blot. SP and CGRP basal release levels were measured by radioimmunoassay (RIA). After that, the DRG cells for RIA were stimulated by capsaicin (300 nmol/L) for 5 min and the culture media were harvested for detecting SP and CGRP release levels by RIA. The neurons exposed to vehicle solution served as vehicle controls. RESULTS: Exposure of butyrate on DRG neurons at higher concentrations (1 mmol/L, 10 mmol/L) for 48 h increased expression mRNA for SP and CGRP than that at lower concentrations (0.01 mmol/L, 0.1 mmol/L) and normal control (P<0.001). VR1 mRNA and VR1 protein expression increased in a dose-dependent manner after exposure of different concentrations of butyrate. Butyrate did not alter the basal release, significantly enhanced neuropeptide release evoked by capsaicin. SP and CGRP release levels in the culture media exposed by butyrate at higher concentrations (1 mmol/L, 10 mmol/L) for 48 h and then stimulated by capsaicin were higher than that at lower concentrations (0.01 mmol/L, 0.1 mmol/L) (P<0.001). The exposure of vehicle solution did not produce any increase of SP and CGRP release from primary cultured DRG neurons. DISCUSSION: Butyrate may promote the expression of mRNA for SP, CGRP and increase sensitivity of capsaicin on SP and CGRP release from primary cultured rat dorsal root ganglion neurons. The promotion of VR1 mRNA and VR1 protein expression by butyrate implicated that VR1 may be involved in the mechanisms of sensory neuropeptide release evoked by capsaicin.

A role for cysteinyl leukotrienes in airway remodeling in a mouse asthma model.

Airway inflammation and remodeling in chronic asthma are characterized by airway eosinophilia, hyperplasia of goblet cells and smooth muscle, and subepithelial fibrosis. We examined the role of leukotrienes in a mouse model of allergen-induced chronic lung inflammation and fibrosis. BALB/c mice, after intraperitoneal ovalbumin (OVA) sensitization on Days 0 and 14, received intranasal OVA periodically Days 14-75. The OVA-treated mice developed an extensive eosinophil and mononuclear cell inflammatory response, goblet cell hyperplasia, and mucus occlusion of the airways. A striking feature of this inflammatory response was the widespread deposition of collagen beneath the airway epithelial cell layer and also in the lung interstitium in the sites of leukocytic infiltration that was not observed in the saline-treated controls. The cysteinyl leukotriene(1) (CysLT(1)) receptor antagonist montelukast significantly reduced the airway eosinophil infiltration, mucus plugging, smooth muscle hyperplasia, and subepithelial fibrosis in the OVA-sensitized/challenged mice. The presence of Charcot-Leyden-like crystals in airway macrophages and the increased interleukin (IL)-4 and IL-13 mRNA expression in lung tissue and protein in BAL fluid seen in OVA-treated mice were also inhibited by CysLT(1) receptor blockade. These data suggest an important role for cysteinyl leukotrienes in the pathogenesis of chronic allergic airway inflammation with fibrosis.