Seasonal variations of macrozoobenthic community trophic structure in the waters adjacent to the seaweed beds of Dalian Island in the North Yellow Sea.

To investigate the effects of algal detritus export on the trophic structure of macrozoobenthic community in the adjacent benthic habitat during the bloom and decline of macroalgae, we collected macrozoobenthos from the adjacent sea area of Dalian Island in the North Yellow Sea in May (the algal bloom period) and August (the algal decay period) of 2020. We quantifyied the seasonal changes in the trophic structure of macrozoobenthic community by using carbon and nitrogen stable isotope techniques. Results showed that δ13C and δ15N values of macrozoo-benthos in May ranged from -23.14‰ to -14.24‰, 6.21‰ to 12.90‰, respectively, and -22.36‰ to -14.13‰, 5.33‰ to 12.00‰, respectively in August. Results of PERMANOVA analysis showed that δ13C values of macrozoobenthos differed significantly between the two months, while δ15N values were not significantly different. Based on the Euclidean distance, the macrozoobenthic communities in both months could be classified into five trophic functional groups. The trophic levels of macrozoobenthos ranged from 2.00 (Nitidotellina minuta) to 3.97 (Glycera onomichiensis) in May and from 2.00 (N. minuta) to 3.96 (G. onomichiensis) in August. The δ13C range, δ15N range, mean centroid distance, total area and corrected standard ellipse areas which represented community trophic structure indices in August were higher than those in May. Our results indicated that the trophic diversity level and trophic niche width of the macrozoobenthic community in the adjacent sea area of the seaweed bed were higher in the algal decline season.

Short- and Long-Term Outcomes in Laparoscopic Versus Open Hepatectomy for Hepatocellular Carcinoma in Elderly Patients: A Systematic Review and Meta-Analysis.

Background: Laparoscopic hepatectomy (LH) is considered a safe and feasible treatment for patients with hepatocellular carcinoma (HCC) in recent studies. However, in elderly patients, application of LH still remains controversial, and the outcomes of LH versus open hepatectomy (OH) have not been fully evaluated. Our objective is to compare the short- and long-term outcomes of LH with OH in elderly patients with HCC. Materials and Methods: All studies comparing LH and OH in elderly patients with HCC were systematically searched in the databases of PubMed, EmBase, and Web of Science. Statistical analysis was conducted using Review Manager 5.3 (Cochrane Collaboration, 2014). The last search was performed on March 20, 2022. Short-term outcomes include blood loss, operation time, blood transfusion, overall and major postoperative complications, mortality, hospital stay, tumor size, and surgical margin. Long-term outcomes include 1-, 3-, and 5-year overall survival (OS); 1-, 3-, and 5-year disease-free survival (DFS); and 1-, 3-, and 5-year recurrence-free survival (RFS). Results: Fourteen studies involving 1596 patients were included in this meta-analysis. The short-term outcomes of LH were a shorter postoperative hospital stay and fewer overall and major postoperative complications (all P < .00001). However, there were no significant differences in operation time, blood loss, blood transfusion rate, surgical margin, tumor size, and mortality. For the long-term outcomes, LH is comparable with OH in terms of 1-, 3-, and 5-year OS; 1-, 3-, and 5-year DFS; and 1-, 3-, and 5-year RFS. Conclusions: Compared with OH, LH is a safe and feasible treatment for elderly patients with HCC.

Analysis of Network Pharmacology and Molecular Docking on Radix Pseudostellariae for Its Active Components on Gastric Cancer.

Radix Pseudostellariae, a traditional Chinese medicine, functions in modulating human immunity and anti-tumor, but its pharmacological mechanism remained unclear. In this study, 8 active components and 91 targets of Radix Pseudostellariae were obtained from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database, and 225 genes related to gastric cancer (GC) were accessed from MalaCards. On the basis of these targets and GC-related genes, a protein-protein interaction (PPI) network was established. Random walk with restart (RWR) analysis was performed on the PPI network with the intersection of targets and GC-related genes as the seeds. The top 50 target genes with high affinity scores were obtained. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that the enrichment of the top 50 genes was mostly presented in the cancer-related biological functions and signaling pathways, such as cellular response to oxidative stress, regulation of apoptotic signaling pathway, and P53 signaling pathway. A drug-component-target network was established, with the top 50 genes being used as key targets. Acacetin and luteolin were revealed to directly act on the core target TP53 in the network. Thus, SwissDock was used to simulate the molecular docking between TP53 protein and acacetin and luteolin. The results of docking simulation presented small estimated ΔG of two small molecules, which were suggested to be potential targets of TP53 protein. Subsequent cellular and molecular experiments confirmed this bioinformatics result. In conclusion, this study predicted the key anti-GC active components and corresponding targets of Radix Pseudostellariae through bioinformatics analysis. The findings underlie the anti-GC mechanism of Radix Pseudostellariae.

Heterophyllin B inhibits the malignant phenotypes of gastric cancer cells via CXCR4.

Heterophyllin B (HB) is a cyclic lipopeptide that has been shown to have anticancer effects. This study intended to further explore the effects and modulatory mechanism of HB in gastric cancer (GC) cells. The binding relationship between HB and CXCR4 was investigated by network pharmacological analysis, molecular docking, and cellular thermal shift assay (CETSA)-WB assay. Cellular assays revealed that HB could restrain GC cell viability, proliferation, invasion and migration by binding to CXCR4. Further studies presented that HB could suppress PI3K/AKT signaling pathway via binding to CXCR4, thus repressing PD-L1 expression. In vivo experiments in nude mice demonstrated that HB constrained PI3K/AKT signaling pathway to suppress GC cell metastasis and PD-L1 expression. In summary, the key target of HB in GC treatment was CXCR4. Cell experiments were employed for the investigation of the mechanism by which HB repressed GC cells. The results confirmed that HB could constrain the malignant progression of GC by the binding of HB into CXCR4 and suppressed PD-L1 expression via hampering PI3K/AKT signaling pathway.

MicroRNA-501-3p targeting TM4SF1 facilitates tumor-related behaviors of gastric cancer cells via EMT signaling pathway.

BACKGROUND: Increasing evidence shows that Transmembrane 4 L6 family member 1(TM4SF1) exerts a critical role in mediating the progression of various tumors. Nevertheless, the exact mechanism of TM4SF1 in gastric cancer (GC) remains unclear. METHODS: Bioinformatics analysis was utilized to analyze TM4SF1 expression in GC tissues. Also, MiRWalk and starBase databases were used to predict the upstream microRNAs which could regulate TM4SF1 expression. Gene set enrichment analysis (GSEA) for TM4SF1 was conducted to screen the potentially involved pathways. Dysregulation of microRNA-501-3p/TM4SF1 was implemented to investigate the regulatory roles of these genes in GC. qRT-PCR and western blot were employed to measure the expression changes of microRNA-501-3p, TM4SF1, and epithelial-mesenchymal transition (EMT) signaling pathway-associated proteins. CCK-8, colony formation, and transwell assays were introduced to examine the biological functions of GC cell lines. RESULTS: TM4SF1 presented a significantly low level in mRNA and protein in GC cells. MicroRNA-501-3p could target TM4SF1 and reduce its expression. Cell function experiments revealed that microRNA-501-3p facilitated cell proliferation, migration, and invasion, while inhibiting cell apoptosis in GC by targeting TM4SF1. EMT-associated proteins were altered by changing microRNA-501-3p/TM4SF1 axis. CONCLUSION: MicroRNA-501-3p regulated EMT signaling pathway by down-regulating TM4SF1 expression and therefore facilitated the malignant progression of GC, which may provide a new potential therapeutic target for the treatment of GC patients.

[Trophic structure of pelagic fishery organism assemblage in the central and western South China Sea in spring revealed by carbon and nitrogen stable isotope analysis]. / åŸºäºŽç¢³æ°®ç¨³å®šåŒä½ç´ çš„å—æµ·ä¸­è¥¿éƒ¨æµ·åŸŸæ˜¥å­£ä¸­ä¸Šå±‚æ¸”ä¸šç”Ÿç‰©ç¾¤è½è¥å »ç»“æž„.

Carbon and nitrogen stable isotope analysis was carried out on pelagic fishery organisms caught in light traps and falling nets in the central and western South China Sea in the spring of 2018. The stable isotope values of the sampled individuals were used to elucidate the isotopic variations for the pelagic fishery organisms, to classify species into trophic functional groups, and to compare the differences of trophic structure among the classified trophic functional groups. The results showed that among 23 fishery species the mean δ13C value of Coryphaena hippurus was the lowest (-17.58‰±0.21‰), and that of Grammistes sexlineatus was the highest (-19.86‰±0.33‰). The mean δ15N values ranged from 8.31‰ in Psenes cyanophrys to (12.46±0.74)‰ in Chirocentrus dorab. The continuous trophic spectrum indicated that the trophic level (TL) for the sampled pela-gic fishery organisms ranged from 3.01 to 4.23, of which 19 species (83% of the total) fell between TL 3.0 and 4.0. The 23 species of fishery organisms were classified into three trophic functional groups, i.e., plankton feeding functional group (PFFG), nekton feeding functional group (NFFG), and mixed feeding functional group (MFFG). The analysis of standard ellipse area (SEA) showed that the PFFG occupied the largest trophic niche width (SEA=1.56‰2), followed by the MFFG (SEA=0.99‰2) and NFFG (SEA=0.31‰2). The MFFG overlapped with PFFG and NFFG in the trophic niche, with a relative percentage of 17% and 26%, respectively. There was no overlap between PFFG and NFFG.

Chronic exposure to electronic cigarettes results in impaired cardiovascular function in mice.

Proponents for electronic cigarettes (E-cigs) claim that they are a safe alternative to tobacco-based cigarettes; however, little is known about the long-term effects of exposure to E-cig vapor on vascular function. The purpose of this study was to determine the cardiovascular consequences of chronic E-cig exposure. Female mice (C57BL/6 background strain) were randomly assigned to chronic daily exposure to E-cig vapor, standard (3R4F reference) cigarette smoke, or filtered air ( n = 15/group). Respective whole body exposures consisted of four 1-h-exposure time blocks, separated by 30-min intervals of fresh air breaks, resulting in intermittent daily exposure for a total of 4 h/day, 5 days/wk for 8 mo. Noninvasive ultrasonography was used to assess cardiac function and aortic arterial stiffness (AS), measured as pulse wave velocity, at three times points (before, during, and after chronic exposure). Upon completion of the 8-mo exposure, ex vivo wire tension myography and force transduction were used to measure changes in thoracic aortic tension in response to vasoactive-inducing compounds. AS increased 2.5- and 2.8-fold in E-cig- and 3R4F-exposed mice, respectively, compared with air-exposed control mice ( P < 0.05). The maximal aortic relaxation to methacholine was 24% and 33% lower in E-cig- and 3R4F-exposed mice, respectively, than in controls ( P < 0.05). No differences were noted in sodium nitroprusside dilation between the groups. 3R4F exposure altered cardiac function by reducing fractional shortening and ejection fraction after 8 mo ( P < 0.05). A similar, although not statistically significant, tendency was also observed with E-cig exposure ( P < 0.10). Histological and respiratory function data support emphysema-associated changes in 3R4F-exposed, but not E-cig-exposed, mice. Chronic exposure to E-cig vapor accelerates AS, significantly impairs aortic endothelial function, and may lead to impaired cardiac function. The clinical implication from this study is that chronic use of E-cigs, even at relatively low exposure levels, induces cardiovascular dysfunction. NEW & NOTEWORTHY Electronic cigarettes (E-cigs) are marketed as safe, but there has been insufficient long-term exposure to humans to justify these claims. This is the first study to report the long-term in vivo vascular consequences of 8 mo of exposure to E-cig vapor in mice (equivalent to ~25 yr of exposure in humans). We report that E-cig exposure increases arterial stiffness and impairs normal vascular reactivity responses, similar to other risk factors, including cigarette smoking, which contribute to the development of cardiovascular disease.

Prenatal and Early Postnatal Exposure to Cigarette Smoke Decreases BDNF/TrkB Signaling and Increases Abnormal Behaviors Later in Life.

BACKGROUND: Cigarette smoke exposure during prenatal and early postnatal periods increases the incidence of a variety of abnormal behaviors later in life. The purpose of this study was to identify the possible critical period of susceptibility to cigarette smoke exposure and evaluate the possibe effects of cigarette smoke during early life on brain-derived neurotrophic factor/neurotrophic tyrosine kinase receptor B signaling in the brain. METHODS: Three different age of imprinting control region mice were exposed to cigarette smoke or filtered air for 10 consecutive days beginning on either gestational day 7 by maternal exposure, or postnatal days 2 or 21 by direct inhalation. A series of behavioral profiles and neurotrophins in brain were measured 24 hours after mice received acute restraint stress for 1 hour on postnatal day 59. RESULTS: Cigarette smoke exposure in gestational day 7 and postnatal day 2 produced depression-like behaviors as evidenced by significantly increased immobility in both tail suspension and forced-swim test. Increased entry latencies, but not ambulation in the open field test, were also observed in the gestational day 7 and postnatal day 2 cigarette smoke exposure groups. Genetic analysis showed that gestational day 7 cigarette smoke exposure significantly altered mRNA level of brain-derived neurotrophic factor/tyrosine kinase receptor B in the hippocampus. However, behavioral profiles and brain-derived neurotrophic factor/tyrosine kinase receptor B signaling were not significantly changed in PND21 cigarette smoke exposure group compared with FA group. CONCLUSIONS: These results suggest that a critical period of susceptibility to cigarette smoke exposure exists in the prenatal and early postnatal period, which results a downregulation in brain-derived neurotrophic factor/tyrosine kinase receptor B signaling in the hippocampus and enhances depression-like behaviors later in life.

Ozone exposure initiates a sequential signaling cascade in airways involving interleukin-1beta release, nerve growth factor secretion, and substance P upregulation.

Previous studies demonstrated that interleukin-1ß (IL-1ß) and nerve growth factor (NGF) increase synthesis of substance P (SP) in airway neurons both after ozone (O3) exposure and by direct application. It was postulated that NGF mediates O3-induced IL-1ß effects on SP. The current study specifically focused on the influence of O3 on IL-1ß, NGF, and SP levels in mice bronchoalveolar lavage fluid (BALF) and whether these mediators may be linked in an inflammatory-neuronal cascade in vivo. The findings showed that in vivo O3 exposure induced an increase of all three proteins in mouse BALF and that O3-induced elevations in both NGF and SP are mediated by the inflammatory cytokine IL-1ß. Further, inhibition of NGF reduced O3 induced increases of SP in both the lung BALF and lung tissue, demonstrating NGF serves as a mediator of IL-1ß effects on SP. These data indicate that IL-1ß is an early mediator of O3-induced rise in NGF and subsequent SP release in mice in vivo.

The role of nodose ganglia in the regulation of cardiovascular function following pulmonary exposure to ultrafine titanium dioxide.

The inhalation of nanosized air pollutant particles is a recognised risk factor for cardiovascular disease; however, the link between occupational exposure to engineered nanoparticles and adverse cardiovascular events remains unclear. In the present study, the authors demonstrated that pulmonary exposure of rats to ultrafine titanium dioxide (UFTiO2) significantly increased heart rate and depressed diastolic function of the heart in response to isoproterenol. Moreover, pulmonary inhalation of UFTiO2 elevated mean and diastolic blood pressure in response to norepinephrine. Pretreatment of the rats ip with the transient receptor potential (TRP) channel blocker ruthenium red inhibited substance P synthesis in nodose ganglia and associated functional and biological changes in the cardiovascular system. In conclusion, the effects of pulmonary inhalation of UFTiO2 on cardiovascular function are most likely triggered by a lung-nodose ganglia-regulated pathway via the activation of TRP channels in the lung.

Substance p regulates environmental tobacco smoke-enhanced tracheal smooth muscle responsiveness in mice.

Environmental tobacco smoke (ETS) is an environmental trigger that leads to airway inflammation and airway hyperresponsiveness (AHR) in susceptible individuals and animals, but the underlying mechanism is not fully understood. Substance P (SP) release from sensory nerve fibers has been linked to AHR. The present experiments characterize the role of SP in tracheal smooth muscle on ETS-increased airway responses. The mice were exposed to either sidestream tobacco smoke (SS), a surrogate to ETS, or filtered air (FA) for 1 day or 5 consecutive days. Contractions of tracheal smooth muscle to SP and electrical field stimulation (EFS) were not significantly altered in 1 of day SS-exposed mice. However, 5 of days SS exposure significantly increased airway smooth muscle contractions to SP and EFS. Administration of CP-99994, an antagonist of the neurokinin (NK)1 receptor, attenuates the SS exposure-enhanced tracheal smooth muscle responses to EFS. Furthermore, the immunohistochemistry showed that SP nerve fibers were increased in tracheal smooth muscle after 5 of days SS exposure. These results suggest that the increased SP production may contribute to SS-enhanced smooth muscle responsiveness in mice trachea.

[Structure and function of Lidao artificial reef ecosystem in Rongcheng of Shandong Province, East China: an evaluation based on Ecopath model].

Based on the annual investigation data of biological resources in Lidao artificial reef zone in 2009, an Ecopath model of the Lidao artificial reef ecosystem was constructed to analyze the energy flow pattern and the system attributes of the ecosystem. The model was consisted of 19 functional groups, basically covering the main processes of the energy flow in the Lidao artificial reef ecosystem. The functional groups were divided according to the relationships of the corresponding positions between appeared fishes and artificial reefs, and the planktonic heterotrophic bacteria were included into the model as a functional group. The fishes appeared in the investigation zone were divided into seven functional groups, and the trophic levels of the functional groups varied from 1.00 to 3.72. The type I fishes had the highest trophic level. The total system throughput was estimated to be 10786.68 t x km(-2) x a(-1), 27% of which flowed to detritus, and 17% flowed out the ecosystem in the forms of fishing and sediment. The total net primary productivity of the system was 4131.97 t x km(-2) x a(-1) and the total energy transfer efficiency was 10.5%. The proportion of the total flow originated from detritus was 39%, and that from primary producers was 61%, indicating that the energy flow was dominated by food web rather than detritus. The ratio of total primary productivity to total respiration of the system was 1.84, the connectivity index was 0.20, and the Finn's cycling index and the mean path length of the energy flow were 4.5% and 2.62, respectively. This study showed that the Lidao artificial reef ecosystem had a relatively low maturity and stability, was at a developing stage, and had weak resistance against outside interference. The ecological environment and the output of fisheries in the artificial reef zone would have inter-annual fluctuations, and thus, the eco-environment restoration of the artificial reef ecosystem could only be realized by the sustainable maintaining of the ecosystem.

Pulmonary exposure of rats to ultrafine titanium dioxide enhances cardiac protein phosphorylation and substance P synthesis in nodose ganglia.

The inhalation of engineered nanoparticles stimulates the development of atherosclerosis and impairs vascular function. However, the cardiac effects of inhaled engineered nanoparticles are unknown. Here, we investigate the effects of ultrafine titanium dioxide (UFTiO(2)) on the heart, and we define the possible mechanisms underlying the measured effects. Pulmonary exposure of rats to UFTiO(2) increased the phosphorylation levels of p38 mitogen-activated protein kinase and cardiac troponin I, but not Akt, in the heart and substance P synthesis in nodose ganglia. Circulatory levels of pro-inflammatory cytokines, and blood cell counts and differentials were not significantly changed after pulmonary exposure. Separately, the incubation of cardiac myocytes isolated from naïve adult rat hearts in vitro with UFTiO(2) did not alter the phosphorylation status of the same cardiac proteins. In conclusion, the inhalation of UFTiO(2) enhanced the phosphorylation levels of cardiac proteins. Such responses are likely independent of systemic inflammation, but may involve a lung-neuron-regulated pathway.

Sensory neural responses to ozone exposure during early postnatal development in rat airways.

Airway infections or irritant exposures during early postnatal periods may contribute to the onset of childhood asthma. The purpose of this study was to examine critical periods of postnatal airway development during which ozone (O(3)) exposure leads to heightened neural responses. Rats were exposed to O(3) (2 ppm) or filtered air for 1 hour on specific postnatal days (PDs) between PD1 and PD29, and killed 24 hours after exposure. In a second experiment, rats were exposed to O(3) on PD2-PD6, inside a proposed critical period of development, or on PD19-PD23, outside the critical period. Both groups were re-exposed to O(3) on PD28, and killed 24 hours later. Airways were removed, fixed, and prepared for substance P (SP) immunocytochemistry. SP nerve fiber density (NFD) in control extrapulmonary (EXP) epithelium/lamina propria (EPLP) increased threefold, from 1% to 3.3% from PD1-PD3 through PD13-PD15, and maintained through PD29. Upon O(3) exposure, SP-NFD in EXP-smooth muscle (SM) and intrapulmonary (INT)-SM increased at least twofold at PD1-PD3 through PD13-PD15 in comparison to air exposure. No change was observed at PD21-PD22 or PD28-PD29. In critical period studies, SP-NFD in the INT-SM and EXP-SM of the PD2-PD6 O(3) group re-exposed to O(3) on PD28 was significantly higher than that of the group exposed at PD19-PD23 and re-exposed at PD28. These findings suggest that O(3)-mediated changes in sensory innervation of SM are more responsive during earlier postnatal development. Enhanced responsiveness of airway sensory nerves may be a contributing mechanism of increased susceptibility to environmental exposures observed in human infants and children.

Prenatal and early, but not late, postnatal exposure of mice to sidestream tobacco smoke increases airway hyperresponsiveness later in life.

BACKGROUND: Cigarette smoke exposure in utero and during early postnatal development increases the incidence of asthma and airway hyperresponsiveness (AHR) later in life, suggesting that a possible critical period of developmental sensitivity exists in the prenatal and early postnatal periods. OBJECTIVE: We investigated mechanisms of susceptibility during critical developmental periods to sidestream smoke (SS) exposure and evaluated the possible effects of SS on neural responses. METHODS: We exposed three different age groups of mice to either SS or filtered air (FA) for 10 consecutive days beginning on gestation day (GD) 7 by maternal exposure or beginning on postnatal day (PND) 2 or PND21 by direct inhalation. Lung function, airway substance P (SP) innervation, and nerve growth factor (NGF) levels in broncho alveolar lavage fluid were measured after a single SS exposure on PND59. RESULTS: Methacholine (MCh) dose response for lung resistance (R(L)) was significantly elevated, and dynamic pulmonary compliance (C(dyn)) was significantly decreased, in the GD7 and PND2 SS exposure groups compared with the FA groups after SS exposure on PND59. At the same time points, the percent area of SP nerve fibers in tracheal smooth muscle and the levels of NGF were significantly elevated. MCh dose-response curves for R(L) and C(dyn), SP nerve fiber density, and the level of NGF were not significantly changed in the PND21 exposure group after SS exposure on PND59. CONCLUSIONS: These results suggest that a critical period of susceptibility to SS exposure exists in the prenatal and early postnatal period of development in mice that results in increased SP innervation, increased NGF levels in the airway, and enhanced MCh AHR later in life.

[Experimental study progress on tribendimidine, artemether and artesunate against Clonorchis sinensis and other trematodes].

Currently praziquantel is one of the major drugs used in treatment of schistosomiasis and other trematode infections. Recent experimental studies indicate that a new anthelmintic, tribendimidine, is used in the treatment of intestinal nematodes, also possesses effect against several species of trematodes including Clonorchis sinensis, Opisthorchis viverrini and Echinostoma caproni. Tribendimidine is even more effective against C. sinensis in rats that a single 300 mg/kg oral dose cures almost all of the animals treated, a lower cure dose than praziquantel (375-500 mg/kg). The anti-malarial drugs artemether and artesunate are not only effective in the prevention of schistosomiasis, but also effective against several species of trematodes, especially C. sinensis. The single oral dose of both drugs to cure or achieve high efficacy in infected rats is 75 mg/kg. This review summarized research progress on tribendimidine, artesunate, and artemether in experimental animals infected with C. sinensis and other species of trematodes.

Effect of diesel exhaust particles on allergic reactions and airway responsiveness in ovalbumin-sensitized brown Norway rats.

We have previously demonstrated that exposure to diesel exhaust particles (DEP) prior to ovalbumin (OVA) sensitization in rats reduced OVA-induced airway inflammation. In the present study, Brown Norway rats were first sensitized to OVA (42.3 +/- 5.7 mg/m3) for 30 min on days 1, 8, and 15, then exposed to filtered air or DEP (22.7 +/- 2.5 mg/m3) for 4 h/day on days 24-28, and challenged with OVA on day 29. Airway responsiveness was examined on day 30, and animals were sacrificed on day 31. Ovalbumin sensitization and challenge resulted in a significant infiltration of neutrophils, lymphocytes, and eosinophils into the lung, elevated presence of CD4+ and CD8+ T lymphocytes in lung draining lymph nodes, and increased production of serum OVA-specific immunoglobulin (Ig)E and IgG. Diesel exhaust particles pre-exposure augmented OVA-induced production of allergen-specific IgE and IgG and pulmonary inflammation characterized by marked increases in T lymphocytes and infiltration of eosinophils after OVA challenge, whereas DEP alone did not have these effects. Although OVA-sensitized rats showed modest response to methacholine challenge, it was the combined DEP and OVA exposure that produced significant airway hyperresponsiveness in this animal model. The effect of DEP pre-exposure on OVA-induced immune responses correlated with an interactive effect of DEP with OVA on increased production of reactive oxygen species (ROS) and nitric oxide (NO) by alveolar macrophages (AM) and alveolar type II (ATII) cells, NO levels in bronchoalveolar lavage fluid, the induction of inducible NO synthase expression in AM and ATII cells, and a depletion of total intracellular glutathione (GSH) in AM and lymphocytes. These results show that DEP pre-exposure exacerbates the allergic responses to the subsequent challenge with OVA in OVA-sensitized rats. This DEP effect may be, at least partially, attributed to the elevated generation of ROS in AM and ATII cells, a depletion of GSH in AM and lymphocytes, and an increase in AM and ATII cell production of NO.

Substance P released from intrinsic airway neurons contributes to ozone-enhanced airway hyperresponsiveness in ferret trachea.

Exposure to ozone (O3) induces airway hyperresponsiveness mediated partly through the release of substance P (SP) from nerve terminals in the airway wall. Although substantial evidence suggests that SP is released by sensory nerves, SP is also present in neurons of airway ganglia. The purpose of this study was to investigate the role of intrinsic airway neurons in O3-enhanced airway responsiveness in ferret trachea. To remove the effects of sensory innervation, segments of ferret trachea were maintained in culture conditions for 24 h before in vitro exposure to 2 parts/million of O3 or air for 1 h. Sensory nerve depletion was confirmed by showing that capsaicin did not affect tracheal smooth muscle responsiveness to cholinergic agonist or contractility responses to electrical field stimulation (EFS). Contractions of isolated tracheal smooth muscle to EFS were significantly increased after in vitro O3 exposure, but the constrictor response to cholinergic agonist was not altered. Pretreatment with CP-99994, an antagonist of the neurokinin 1 receptor, attenuated the increased contraction to EFS after O3 exposure but had no effect in the air exposure group. The number of SP-positive neurons in longitudinal trunk ganglia, the extent of SP innervation to superficial muscular plexus nerve cell bodies, and SP nerve fiber density in tracheal smooth muscle all increased significantly after O3 exposure. The results show that release of SP from intrinsic airway neurons contributes to O3-enhanced tracheal smooth muscle responsiveness by facilitating acetylcholine release from cholinergic nerve terminals.