Biotransformation of cyclosporin in primary rat,porcine and human liver cell co-cultures

The purpose of this study was to investigate the species-specific cyclosporin biotransformation in primary rat, human, and porcine liver cell cultures, and to investigate the suitability of a modified sandwich culture technique with non-purified liver cell co-cultures for drug metabolism studies. A sandwich culture was found to enhance hepatocellular metabolic activity and improve cellular morphology and ultrastructure. The cyclosporin metabolites AM9 and AM1 were formed in porcine and human liver cell sandwich co-cultures at levels corresponding to the respective in vivo situations. In contrast, metabolite profiles in rat hepatocytes were at variance with the in vivo situation. However, for all cell types, the overall metabolic activity was positively influenced by sandwich co-culture. The initial levels of albumin synthesis were higher in sandwich cultures than in those without matrix overlay. It is hypothesized that the sandwich culture system provides an improved microenvironment and is, therefore, an advantageous tool for in vitro studies of drug metabolism.     

The pulmonary deposition and retention of indium-111 labeled ultrafine carbon particles in healthy individuals

Context: Particulate air pollution, for example, from ultrafine (UF) particles, has negative health effects. However, there is still limited knowledge regarding the fate of inhaled particles in the human body.

Objectives: To describe the normal lung deposition and 1 week particle retention of indium-111 labeled UF carbon particles in healthy subjects. Additionally, the possibility to extend the follow-up period to 4 weeks was also investigated for one of the subjects.

Results: The cumulative pulmonary particle clearance 1 week post-administration, corrected for activity leaching and mucocilliary transport of activity deposited in the central airways, was 4.3?±?8.5% (average ± standard deviation at group level), with marginal translocation of particles from lungs to blood, 0.3%. There was no observable elimination of particles from the body via urine. Seven days after exposure, the cumulated activity leaching was 3% (group level), which indicates a stable bonding between the particles and Indium-111. The volunteer followed for a total of 4 weeks, showed a cumulative decrease of activity retention in the lungs of 10.5%. After correction for activity leaching and clearance from central airway deposition, the estimated particle clearance was about 2%.

Conclusions: No evidence for particle translocation from the lungs could be proven 7 days after exposure. It is possible to follow-up Indium-111 labeled UF carbon particles at least 1 month post-administration without increasing the administered activity.     

Diesel exhaust particles in blood trigger systemic and pulmonary morphological alterations

Short-term exposure to elevated levels of particulate matter is associated with increased respiratory and cardiovascular mortality and morbidity. However, the mechanisms underlying these effects are still unclear. Recent studies have suggested that inhaled ultrafine particles are able to translocate into the bloodstream. To gain more insight into this potential mechanism, we studied the effect of diesel exhaust particles (DEP, 0.02 and 0.1mg/kg), 48h following their intravenous administration, on systemic inflammation and both pulmonary and cardiac morphological alterations in rats. The intravenous administration of DEP (0.1mg/kg) triggered systemic inflammation characterized by an increase of monocyte and granulocyte numbers. Both doses of DEP caused a reduction of the number of red blood cells (RBC) and haemoglobin concentration. Transmission electron microscopy analysis of RBC after in vitro incubation (5microg/ml) or in vivo administration of DEP, revealed the presence of ultrafine-sized aggregates of DEP within the RBC. Larger aggregates were also taken up by the RBC. Moreover, while the myocardial morphology and capillary bed were not affected by DEP exposure, the lungs of rats exposed to DEP (0.02 and 0.1mg/kg) showed clear evidence of inflammation, characterized by neutrophils infiltration. Stereological analysis revealed an increase in interalveolar wall thickness and a decrease in numbers of alveolar sacs per unit area of lung parenchyma of rat exposed to DEP. We conclude that 48h after their systemic administration, DEP cause systemic and pulmonary morphological alterations.     

Quantification of extrapulmonary translocation of intratracheal-instilled particles in vivo in rats: effect of lipopolysaccharide

Particulate air pollution is associated with respiratory and cardiovascular morbidity and mortality. However, important uncertainties remain in the quantification of extrapulmonary translocation of ultrafine particles into blood circulation. Therefore, the widely used radioiodinated technique was applied to radiolabel polystyrene particles with an average diameter of 56.4 and 202 nm, respectively. The extrapulmonary distribution of these particles (3.7 x 10(5) Bq/rat) was quantified at 0.5, 2, 24 and 120 h after intratracheal instillation in rats. Moreover, we have taken into account the possible involvement of pulmonary inflammation in this process. Rats which received a single intratracheal instillation of free 125I or a single intravenous injection of labeled ultrafine particles served as control. The results indicated that the pulmonary deposition of radioactivity was almost unchanged for both sizes. Only small amounts of radioactivity (1.64-2.49%) were recovered in blood shortly after administration of both types of particle, in healthy rats. However, the extent of particle translocation into the blood of the ultrafine size following the pretreatment with lipopolysaccharides was significantly higher (from 1.96 +/- 0.67 to 4.73 +/- 0.31%) compared to larger particles (from 2.19 +/- 0.77 to 2.21 +/- 0.64%). In conclusion, our findings suggest that only a small fraction of intratracheal-instilled ultrafine particles can pass rapidly into systemic circulation, but this translocation is markedly increased following LPS pretreatment. Thus, pulmonary inflammation seems to play a major role in enhancing the extrapulmonary translocation of particles.     

Size effect of intratracheally instilled particles on pulmonary inflammation and vascular thrombosis

Particulate air pollution is associated with cardiorespiratory effects and ultrafine particles (UFPs, diameter < 100 nm) are believed to play an important role. We studied the acute (1 h) effect of intratracheally instilled unmodified (60 nm), negatively charged carboxylate-modified (60 nm), or positively charged amine-modified (60 or 400 nm) polystyrene particles on bronchoalveolar lavage (BAL) indices and on peripheral thrombosis in hamster. The latter was assessed by measuring the extent of photochemically induced thrombosis in a femoral vein via transillumination. Unmodified and negative UFPs did not modify thrombosis and BAL indices. Positive UFPs increased thrombosis at 500 microg per animal (+ 341 +/- 96%) and at 50 microg per animal (+ 533 +/- 122%), but not at 5 microg per animal. Neutrophils, lactate dehydrogenase, and histamine were increased in BAL at all these doses but protein concentration was increased only at 500 microg per animal. Positive 400-nm particles (500 microg per animal) did not affect thrombosis, although they led to a neutrophil influx and an increase in BAL proteins and histamine. Using the Platelet Function Analyser (PFA-100), the platelets of hamsters were activated by the in vitro addition of positive UFPs and 400-nm particles to blood. We conclude that intratracheally administered positive ultrafine and 400-nm particles induce pulmonary inflammation within 1 h. Positive UFPs, but not the 400-nm particles enhance thrombosis. Hence, particle-induced lung inflammation and thrombogenesis can be partially uncoupled.     

Effects of combustion-derived ultrafine particles and manufactured nanoparticles on heart cells in vitro

Evidence from epidemiological studies indicates that acute exposure to airborne pollutants is associated with an increased risk of morbidity and mortality attributed to cardiovascular diseases. The present study investigated the effects of combustion-derived ultrafine particles (diesel exhaust particles) as well as engineered nanoparticles (titanium dioxide and single-walled carbon nanotubes) on impulse conduction characteristics, myofibrillar structure and the formation of reactive oxygen species in patterned growth strands of neonatal rat ventricular cardiomyocytes in vitro. Diesel exhaust particles as well as titanium dioxide nanoparticles showed the most pronounced effects. We observed a dose-dependent change in heart cell function, an increase in reactive oxygen species and, for titanium dioxide, we also found a less organized myofibrillar structure. The mildest effects were observed for single-walled carbon nanotubes, for which no clear dose-dependent alterations of theta and dV/dt(max) could be determined. In addition, there was no increase in oxidative stress and no change in the myofibrillar structure. These results suggest that diesel exhaust as well as titanium dioxide particles and to a lesser extent also single-walled carbon nanotubes can directly induce cardiac cell damage and can affect the function of the cells.     

Effects of methylmercury on primary brain cells in mono- and co-culture.

We report on the uptake of MeHg in astrocytes and neurons, as well as specific indicators of neurotoxicity. Cerebellar granule neurons and astrocytes separately and in co-culture were cultured in the presence of MeHg and changes in 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyltetrazolium bromide (MTT)-reduction, lactate dehydrogenase (LDH) leakage, and cellular content of glutathione and amino acids were used as indicators of MeHg toxicity. Mitochondria in cortical astrocytes were slightly more sensitive than those in cerebellar astrocytes to the toxic effects of MeHg; furthermore, cellular integrity was better preserved in cerebellar astrocytes. When neurons and astrocytes from cerebellum were incubated in separable co-cultures using inserts, the astrocytes showed cellular damage at lower exposure to MeHg while neurons showed less changes compared to respective cell types in mono-cultures. Mercury uptake studies at 25 microM MeHg (10% serum present) showed that for neurons in co-culture the uptake was 1/3 compared to mono-cultures. In contrast, for astrocytes in co-culture, uptake was increased by 75%. A MeHg concentration-dependent increase of glutamate content in mono-cultures was noted. When MeHg concentration was increased to 10, 25, or 50 microM, neurons in co-cultures decreased their glutamate content, whereas astrocytes showed an increase. Other amino acids, such as glutamine, serine, valine, isoleucine, taurine, and phenylalanine were unaffected by MeHg. Glutathione content showed MeHg concentration-dependent changes in astrocytes and was increased in neurons in co-culture incubated with 5 microM MeHg. In conclusion, astrocytes appear to increase neuronal resistance, indicating a possible protective role for astrocytes in MeHg neurotoxicity.     

Synergistic effects of exposure to concentrated ambient fine pollution particles and nitrogen dioxide in humans

Context: Exposure to single pollutants e.g. particulate matter (PM) is associated with adverse health effects, but it does not represent a real world scenario that usually involves multiple pollutants.

Objectives: Determine if simultaneous exposure to PM and NO₂ results in synergistic interactions.

Materials and methods: Healthy young volunteers were exposed to clean air, nitrogen dioxide (NO₂, 0.5 ppm), concentrated fine particles from Chapel Hill air (PM_2.5CAPs, 89.5?±?10.7 µg/m³), or NO₂+PM_2.5CAPs for 2?h. Each subject performed intermittent exercise during the exposure. Parameters of heart rate variability (HRV), changes in repolarization, peripheral blood endpoints and lung function were measured before and 1 and 18?h after exposure. Bronchoalveolar lavage (BAL) was performed 18?h after exposure.

Results: NO₂ exposure alone increased cholesterol and HDL 18?h after exposure, decreased high frequency component of HRV one and 18?h after exposure, decreased QT variability index 1?h after exposure, and increased LDH in BAL fluid. The only significant change with PM_2.5CAPs was an increase in HDL 1?h after exposure, likely due to the low concentrations of PM_2.5CAPs in the exposure chamber. Exposure to both NO₂ and PM_2.5CAPs increased BAL α1-antitrypsin, mean t wave amplitude, the low frequency components of HRV and the LF/HF ratio. These changes were not observed following exposure to NO₂ or PM_2.5CAPs alone, suggesting possible interactions between the two pollutants.

Discussion and conclusions: NO₂ exposure may produce and enhance acute cardiovascular effects of PM_2.5CAPs. Assessment of health effects by ambient PM should consider its interactions with gaseous copollutants.     

Enhanced insulin resistance in diet-induced obese rats exposed to fine particles by instillation

Context: Epidemiological studies indicate that diabetes is a sub-population at risk for particulate matter (PM)-associated cardiovascular disease (CVD). Recent animal studies suggested PM might impair glucose tolerance, which may lead to CVD. However, the mechanism remains unclear.

Objective: To investigate further the PM effect on insulin resistance (IR) in obese and healthy rats.

Materials and methods: Male Sprague–Dawley rats were fed with either a high fat diet (HFD) or normal chow diet (NCD) for 6 weeks. Both groups were then further assigned to receive PM₁₀, PM_2.5 or normal saline (n?=?6 per group) by intratracheal instillation (IT) once per week for 3 weeks. Fasting glucose and insulin were measured and homeostasis model assessment-insulin resistance (HOMA-IR) was used to assess IR. Biochemistry tests and lipids profile were examined at sacrifice. The markers of fibrinogen and [nitrate+nitrite], an indicator of nitric oxide (NO) production, C-reactive protein (CRP) and white blood counts (WBCs) in peripheral blood were also determined.

Results: Body weight, insulin and HOMA-IR of HFD rats were significantly increased compared with a NCD after 6 weeks. In HFD rats, PM_2.5 increased HOMA-IR after first IT and further increased HOMA-IR at the end of exposure. However, this increase was not observed in NCD rats and after PM₁₀ exposure. Increased fibrinogen was also noted after chronic PM_2.5 exposure in both HFD and NCD rats.

Discussion and conclusion: Exposure to PM_2.5 enhanced IR in HFD rats but not in NCD rats. Obese subjects with IR may be a susceptible population to particulate air pollution.     

Air pollution and emergency room visits for cardiac arrhythmia in a subtropical city: Taipei,Taiwan

This study was undertaken to determine whether there was an association between air pollutant levels and emergency room (ER) visits for cardiac arrhythmia in Taipei, Taiwan. ER visits for cardiac arrhythmia and ambient air pollution data for Taipei were obtained for the period 2000–2006. The relative risk of ER visits was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single-pollutant model, on warm days (≥23°C), statistically significant positive associations were found for all pollutants except SO₂. On cool days (<23°C), all pollutants were also significantly associated with the number of ER visits for cardiac arrhythmia, except SO₂. For the two-pollutant model, results for O₃ and NO₂ remained statistically significant on both warm and cool days. This study provides evidence that higher levels of ambient air pollutants increase the risk of ER visits for cardiac arrhythmia.     

Biological effects of desert dust in respiratory epithelial cells and a murine model

Abstract

As a result of the challenge of recent dust storms to public health, we tested the postulate that desert dust collected in the southwestern United States imparts a biological effect in respiratory epithelial cells and an animal model. Two samples of surface sediment were collected from separate dust sources in northeastern Arizona. Analysis of the PM₂₀ fraction demonstrated that the majority of both dust samples were quartz and clay minerals (total SiO₂ of 52 and 57%). Using respiratory epithelial and monocytic cell lines, the two desert dusts increased oxidant generation, measured by Amplex Red fluorescence, along with carbon black (a control particle), silica, and NIST 1649 (an ambient air pollution particle). Cell oxidant generation was greatest following exposures to silica and the desert dusts. Similarly, changes in RNA for superoxide dismutase-1, heme oxygenase-1, and cyclooxygenase-2 were also greatest after silica and the desert dusts supporting an oxidative stress after cell exposure. Silica, desert dusts, and the ambient air pollution particle NIST 1649 demonstrated a capacity to activate the p38 and ERK1/2 pathways and release pro-inflammatory mediators. Mice, instilled with the same particles, showed the greatest lavage concentrations of pro-inflammatory mediators, neutrophils, and lung injury following silica and desert dusts. We conclude that, comparable to other particles, desert dusts have a capacity to (1) influence oxidative stress and release of pro-inflammatory mediators in respiratory epithelial cells and (2) provoke an inflammatory injury in the lower respiratory tract of an animal model. The biological effects of desert dusts approximated those of silica.     

Modeling emissions from CAFO poultry farms in Poland and evaluating potential risk to surrounding populations

The world-wide use of concentrated animal feeding operations (CAFOs) for livestock production demands the need to evaluate the potential impact to public health. We estimated the exposure of various airborne pollutants for populations residing in close proximity to 10 poultry CAFOs located in Central Poland. Ammonia (NH₃), carbon dioxide (CO₂), carbon monoxide (CO), hydrogen sulfide (H₂S), methane (CH₄), nitrogen dioxide (NO₂), nitrous oxide (N₂O), sulfur dioxide (SO₂), and organic dust were the pollutants of interest for this study. Because no monitoring data were available, we used the steady-state Gaussian dispersion model AERMOD to estimate pollutant concentrations for the exposed population in order to calculate the hazard index (HI) for a combined mixture of chemicals. Our results indicate that while the levels of certain pollutants are expected to exceed background levels commonly found in the environment they did not result in calculated hazard indexes which exceeded unity suggesting low potential for adverse health effects for the surrounding community for the mixture of chemicals. The study was conducted through a cooperation between the Agency for Toxic Substances and Disease Registry (ATSDR) in the USA and the Nofer Institute of Occupational Medicine (NIOM) in Poland.     

Vanadium pentoxide-coated ultrafine titanium dioxide particles induce cellular damage and micronucleus formation in V79 cells

Surface-treated titanium dioxide (TiO(2)) particles coated with vanadium pentoxide (V(2)O(5)) are used industrially for selective catalytic reactions such as the removal of nitrous oxide from exhaust gases of combustion power plants (SCR process) and in biomaterials for increasing the strength of implants. In the present study, untreated ultrafine TiO(2) particles (anatase, diameter: 30-50 nm) and vanadium pentoxide (V(2)O(5))-treated anatase particles were tested for their cyto- and genotoxic effects in V79 cells (hamster lung fibroblasts). Cytotoxic effects of the particles were assessed by trypan blue exclusion, while genotoxic effects were investigated by micronucleus (MN) assay. In addition, the generation of reactive oxygen species (ROS) was determined by the acellular method of electron spin resonance technique (ESR) and by the cellular technique of determination of thiobarbituric acid-reactive substances (TBARS). Our results demonstrate that V(2)O(5)-treated TiO(2) particles induce more potent cyto- and genotoxic effects than untreated particles. Further, acellular and cellular radical formation was more pronounced with V(2)O(5)-anatase than untreated anatase. Thus, data indicate that V(2)O(5)-treated TiO(2) particles were more reactive than natural anatase and capable of inducing DNA damage in mammalian cells through production of free radicals.     

Effects of ultrafine diesel exhaust particles on oxidative stress generation and dopamine metabolism in PC-12 cells

A major constituent of urban air pollution is diesel exhaust, a complex mixture of gases, chemicals, and particles. Recent evidence suggests that exposure to air pollution can increase the risk of a fatal stroke, cause cerebrovascular damage, and induce neuroinflammation and oxidative stress that may trigger neurodegenerative diseases, such as Parkinson's disease. The specific aim of this study was to determine whether ultrafine diesel exhaust particles (DEPs), the particle component of exhaust from diesel engines, can induce oxidative stress and effect dopamine metabolism in PC-12 cells. After 24 h exposure to DEPs of 200 nm or smaller, cell viability, ROS and nitric oxide (NO₂) generation, and levels of dopamine (DA) and its metabolites, (dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA)), were evaluated. Results indicated cell viability was not significantly changed by DEP exposure. However, ROS showed dramatic dose-dependent changes after DEP exposure (2.4 fold increase compared to control at 200 μg/mL). NO₂ levels were also dose-dependently increased after DEP exposure. Although not in a dose-dependent manner, upon DEP exposure, intracellular DA levels were increased while DOPAC and HVA levels decreased when compared to control. Results suggest that ultrafine DEPs lead to dopamine accumulation in the cytoplasm of PC-12 cells, possibly contributing to ROS formation. Further studies are warranted to elucidate this mechanism.     

(Anti)estrogenic effects of phytochemicals on human primary mammary fibroblasts, MCF-7 cells and their co-culture

In the public opinion, phytochemicals (PCs) present in the human diet are often considered beneficial (e.g. by preventing breast cancer). Two possible mechanisms that could modulate tumor growth are via interaction with the estrogen receptor (ER) and inhibition of aromatase (CYP19). Multiple in vitro studies confirmed that these compounds act estrogenic, thus potentially induce tumor growth, as well as aromatase inhibitory, thus potentially reduce tumor growth. It is thought that in the in vivo situation breast epithelial (tumor) cells communicate with surrounding connective tissue by means of cytokines, prostaglandins and estradiol forming a complex feedback mechanism. Recently our laboratory developed an in vitro co-culture model of healthy mammary fibroblasts and MCF-7 cells that (at least partly) simulated this feedback mechanism (M. Heneweer et al., TAAP vol. 202(1): 50-58, 2005). In the present study biochanin A, chrysin, naringenin, apigenin, genistein and quercetin were studied for their estrogenic properties (cell proliferation, pS2 mRNA) and aromatase inhibition in MCF-7 breast tumor cells, healthy mammary fibroblasts and their co-culture. The proliferative potency of these compounds in the MCF-7 cells derived from their EC(50)s decreased in the following order: estadiol (4*10(-3) nM)>biochanin A (9 nM)>genistein (32 nM)>testosterone (46 nM)>naringenin (287 nM)>apigenin (440 nM)>chrysin (4 microM). The potency to inhibit aromatase derived from their IC(50)s decreased in the following order: chrysin (1.5 microM)>naringenin (2.2 microM)>genistein (3.6 microM)>apigenin (4.1 microM)>biochanin A (25 microM)>quercetin (30 microM). The results of these studies show that these PCs can induce cell proliferation or inhibit aromatase in the same concentration range (1-10 microM). Results from co-cultures did not elucidate the dominant effect of these compounds. MCF-7 cell proliferation occurs at concentrations that are not uncommon in blood of individuals using food supplements. Results also indicate that estrogenicity of these PCs is quantitatively more sensitive than aromatase inhibition. It is suggested that perhaps a more cautionary approach should be taken for these PCs before taken as food supplements.     

Effects of serotonin in failing cardiac ventricle: signalling mechanisms and potential therapeutic implications

Previously, cardioexcitation by serotonin (5-hydroxytryptamine, 5-HT) was believed to be confined to atria in mammals including man, and mediated through 5-HT₄ receptors in pig and man, but 5-HT_2A receptors in rat. Recent studies, reviewed here, demonstrate that functional 5-HT₄ receptors can be revealed in porcine and human ventricular myocardium during phosphodiesterase inhibition, and that 5-HT₄ receptor mRNA is increased in human heart failure. In rats, functional 5-HT₄ and 5-HT_2A receptors appear in the cardiac ventricle during heart failure and mediate inotropic responses through different mechanisms. 5-HT_2A receptor signalling resembles that from α₁-adrenoceptors and causes inotropic effects through increased myosin light chain phosphorylation, resulting in Ca²⁺ sensitisation. 5-HT₄ receptor signalling resembles that from β-adrenoceptors and causes inotropic effects through a pathway involving cAMP and PKA-mediated phosphorylation of proteins involved in Ca²⁺ handling, resulting in enhanced contractility through increased Ca²⁺ availability. Cyclic AMP generated through 5-HT₄ receptor stimulation seems more efficiently coupled to increased contractility than cAMP generated through β-adrenoceptor stimulation. Increasing contractility through cAMP is considered less energy efficient than Ca²⁺ sensitisation and this may be one reason why β-adrenoceptor antagonism is beneficial in heart failure patients. Treatment of heart failure rats with the 5-HT₄ antagonist SB207266 (piboserod) resulted in potentially beneficial effects, although small. Further studies are needed to clarify if such treatment will be useful for patients with heart failure.     

Morphological changes and viability of primary cultured human ocular trabecular meshwork cells after exposure to air

PurposeTo investigate the possible toxic effect of air exposure for an in vitro model of primary human ocular trabecular meshwork cells (HTM).MethodsHTM were isolated from five donor eyes and cultivated at 37 °C. After reaching confluence the cells were seeded on two well chamber slides. The chamber slides were turned upside down in a Petri culture dish full of culture medium and filled with air using a 5 ml syringe, starting this way the exposure of the cells to the air. Subsequently they were placed in the incubation chamber at 37 °C. Six groups of HTM cultures were set up: group 1 consisted of samples in which HTM were exposed to air for 30 min, group 2 for 1 h, group 3 for 3 h, group 4 for 6 h, group 5 for 12 h and group 6 for 24 h.ResultsAt 3 h after exposure, the morphology of the cells was still intact, at 6 h few cells appeared deformed and exhibited characteristics of more senescent cells. At 12 h after exposure to air the HTM cells started losing their typical morphology and appeared enlarged and compromised. Viability was superior to 94% in groups 1–3 while for groups 4, 5, 6 it was 82.7%, 39.5% and 12.7% respectively.ConclusionThe toxic effect of air exposure for the studied in vitro model of HTM is not significant for the time period of one to three hours. However it starts reducing viability and alternating morphology 6 h after exposure until the time period of 24 h, where the percentage of living cells is drastically decreased. Therefore, we suggest that the use of an air bubble especially in glaucomatous patients should be applied with caution.     

Influence of experimental type 1 diabetes on the pulmonary effects of diesel exhaust particles in mice

Epidemiologically, exposure to particulate air pollution is associated with increases in morbidity and mortality, and diabetics are especially vulnerable to effects of particles. This study was carried out to determine the respiratory effect of diesel exhaust particles (DEP; 0.4 mg/kg) on mice rendered diabetic by the injection of streptozotocin or vehicle (control). Four weeks following induction of diabetes, the animals were intratracheally instilled (i.t.) with DEP (0.4 mg/kg) or saline. 24 h later, the measurement of airway reactivity to methacholine in vivo by a forced oscillation technique showed a significant and dose-dependent increase in airway resistance in non-diabetic mice exposed to DEP versus non-diabetic mice exposed to saline. Similarly, the airway resistance was significantly increased in diabetic mice exposed to DEP versus diabetic mice exposed to saline. Nevertheless, there was no difference in the airway resistance between diabetic and non-diabetic mice after i.t. administration of DEP. Following DEP administration there were neutrophil polymorphs infiltration of pulmonary interalveolar septae and the alveolar spaces with many macrophages containing DEP in both diabetic and non-diabetic mice. Interestingly, apoptotic cells were only found in the examined lung sections from diabetic mice exposed to DEP. Total proteins and albumin concentrations in bronchoalveolar lavage (BAL) fluid, markers for increase of epithelial permeability, were significantly increased in diabetic mice exposed to DEP compared to saline-treated diabetic and DEP-treated non diabetic mice. Superoxide dismutase activity and reduced glutathione concentration in BAL were significantly decreased in diabetic mice exposed to DEP compared to saline-treated diabetic and DEP-treated non diabetic mice. Moreover, tumor necrosis factor α (TNFα) concentrations were significantly increased in diabetic mice exposed to DEP compared to saline-treated diabetic and DEP-treated non diabetic mice. We conclude that, at the dose and time point investigated, DEP equally increased airway resistance and caused infiltration of inflammatory cells in the lung of both diabetic and non-diabetic mice. However, the occurrence of oxidative stress, the presence lung apoptotic cells and the increase of total proteins, albumin and TNFα in BAL fluid were only seen in DEP-exposed diabetic mice suggesting an increased respiratory susceptibility to particulate air pollution.     

MSCs修饰受体胸腺的异种心脏移植中Th2细胞的表达研究

目的研究胸腺修饰对异种移植免疫排斥反应的影响,探讨Th2细胞的作用。方法将供体豚鼠(20只)和受体SD大鼠(20只)随机分成四组,A组(对照组);B组(胸腺修饰IT组);C组(CVF组);D组(IT加CVF组),每组各10只,5只供体豚鼠,5只受体SD大鼠。观测指标:脾脏GATA-3,CCR3变化。结果脾脏GATA-3的表达,测得灰度值分别为:A组:80.718±1.650,B组:81.510±1.890,C组:166.160±7.360,D组:115.074±3.090;D组表达较C组弱,差异有统计学意义(P<0.05)。C组的脾脏GATA-3、CCR3免疫组化较D组表达明显增强。结论 Th2细胞的增殖通过豚鼠MSCs修饰大鼠胸腺被有效抑制,从而使大鼠IgG类诱生异种抗体的产生也受到抑制。