Kinetics of nickel binding in hepatic and renal cytosol of63NiCl2-treated rats

Elution profiles of nickel-binding protein were investigated in hepatic and renal cytosol of rats at various time intervals (6, 16, 24, and 48 h) after intraperitoneal administration of⁶³Ni (1 mg Ni/kg. B. Wt. = 400 µCi as⁶³NiCl₂). The nickel-binding proteins were characterized in terms of absorbance at 254 nm, sulfhydryl content, and⁶³Ni counts. The results demonstrated that in liver it was bound to both high as well as low mol wt sulfhydryl proteins and glutathione-like moiety with a maximum incorporation at 16 h, after which it declined and by 48 h, very little⁶³Ni was associated with the bioligands. In kidney the incorporation of⁶³Ni was approximately 400-fold higher than liver and most of⁶³Ni was associated with the low mol. wt. sulfhydryl moiety. Kidney also exhibited maximum incorporation of⁶³Ni at 16 h that was metabolized by 48 h.     

Distribution of nickel,zinc, and copper in rat organs after oral administration of nickel(II) chloride

The distribution of Ni administered as NiCl₂ · 6H₂O in the drinking water (300 and 1200 ppm Ni for 90 d) was studied using male Wistar rats. Next, the effect of Ni on the concentration of zinc (Zn) and copper (Cu) in selected organs and serum was measured. The metals were analyzed in the liver, kidney, lung, spleen, brain, and serum by electrothermal (Ni) or flame (Zn, Cu) atomic absorption spectrophotometry. The results indicate that exposed rats drank less nickel solutions than the volume of water drunk by controls, but there was no mortality of animals. In comparison to control animals, a very high increase in Ni levels was found in the kidney and then lung and serum of all exposed rats. In the liver, spleen, and brain, the metal accumulation was lower. A directly proportional relation between the nickel intake and its deposition was observed in the collected organs and in the serum. The metal level did not change significantly in the course of exposure (the first analysis was after 30 d). The administration of 300 ppm Ni did not affect the zinc and copper concentration in studied organs, except the serum, where zinc content was significantly reduced. At a dose of 1200 ppm Ni, these metals were found to be depressed in the liver, kidney, serum (zinc), and copper in the kidney.     

Acorus calamus extracts and nickel chloride: prevention of oxidative damage and hyperproliferation response in rat kidney

Nickel, a major environmental pollutant, is known for its clastogenic, toxic, and carcinogenic potential. In this article, we report the effect of Acorus calamus on nickel chloride (NiCl2)-induced renal oxidative stress, toxicity, and cell proliferation response in male Wistar rats. NiCl2 (250 micromol/kg body weight/mL) enhanced reduced renal glutathione content (GSH), glutathione- S-transferase (GST), glutathione reductase (GR), lipid peroxidation (LPO), H2O2 generation, blood urea nitrogen (BUN), and serum creatinine with a concomitant decrease in the activity of glutathione peroxidase (GPx) (p < 0.001). NiCl2 administration also dose-dependently induced the renal ornithine decarboxylase (ODC) activity several-fold as compared to salinetreated control rats. Similarly, renal DNA synthesis, which is measured in terms of [3H] thymidine incorporation in DNA, was elevated following NiCl2 treatment. Prophylactic treatment of rats with A. calamus (100 and 200 mg/kg body weight po) daily for 1 wk resulted in the diminution of NiCl2- mediated damage, as evident from the downregulation of glutathione content, GST, GR, LPO, H2O2 generation, BUN, serum creatinine, DNA synthesis (p < 0.001), and ODC activity (p < 0.01) with concomitant restoration of GPx activity. These results clearly demonstrate the role of oxidative stress and its relation to renal disfunctioning and suggest a protective effect of A. calamus on NiCl2-induced nephrotoxicity in a rat experimental model.     

Acorus calamus extracts and nickel chloride

Nickel, a major environmental pollutant, is known for its clastogenic, toxic, and carcinogenic potential. In this article, we report the effect of Acorus calamus on nickel chloride (NiCl₂)-induced renal oxidative stress, toxicity, and cell proliferation response in male Wistar rats. NiCl₂ (250 μmol/kg body weight/mL) enhanced reduced renal glutathione content (GSH) glutathione-S-transferase (GST), glutathione reductase (GR), lipid peroxidation (LPO), H₂O₂ generation, blood urea nitrogen (BUN), and serum creatinine with a concomitant decrease in the activity of glutathione peroxidase (GPx) (p<0.001). NiCl₂ administration also dose-dependently induced the renal ornithine decarboxylase (ODC) activity several-fold as compared to salinetreated control rats. Similarly, renal DNA synthesis, which is measured in terms of [³H] thymidine incorporation in DNA, was elevated following NiCl₂ treatment. Prophylactic treatment of rats with A. calamus (100 and 200 mg/kg body weight po) daily for 1 wk resulted in the diminution of NiCl₂-mediated damage, as evident from the downregulation of glutathione content, GST, GR, LPO, H₂O₂ generation, BUN, serum creatinine, DNA synthesis (p<0.001), and ODC activity (p<0.01) with concomitant restoration of GPx activity. These results clearly demonstrate the role of oxidative stress and its relation to renal disfunctioning and suggest a protective effect of A. calamus on NiCl₂-induced nephrotoxicity in a rat experimental model.     

Allergic contact dermatitis induced by intratracheal administration of hapten

It is known that the skin is the natural route for induction of allergic contact dermatitis (ACD). Because the lung is another potential portal of entry for sensitizing chemicals, studies were performed to evaluate immune responses to haptens deposited in the lung. As a result, a new method for inducing ACD was developed. Intratracheal (IT) inoculation of 2,4,6-trinitrobenzene sulfonic acid (TNBS) led to maximal ear swelling 24 hr after challenge on the ear with 2,4,6-trinitrochlorobenzene (TNCB) in carrier. This response was specific for immunizing hapten. Furthermore, it was equally possible to induce ACD by intratracheal inoculation of trinitrophenyl- (TNP) modified bronchoalveolar cells (BAC) or haptenated spleen cells. Adoptive transfer studies demonstrated that the hypersensitivity that resulted from IT inoculation of TNBS or TNP BAC could be transferred with cells. With a monoclonal anti-hamster Ia reagent, it was demonstrated that, like Langerhans cells, 80 to 90% of cells in the bronchial lavage fluid expressed Ia determinants on their membrane. These cells were morphologically indistinguishable from macrophages. Because an individual is capable of being sensitized when hapten is introduced by the pulmonary or epicutaneous routes, the possibility is raised that the alveolar macrophages in the lung possess a similar capability for antigen presentation of hapten in the induction of ACD as does the Langerhans cell.     

Effects of intratracheal instillation of TNF-alpha on surfactant metabolism.

Tumor necrosis factor-alpha (TNF-alpha) has been shown to play an integral role in the pathogenesis of the acute respiratory distress syndrome. This disorder is characterized by a deficiency of alveolar surfactant, a surface-active material that is composed of key hydrophobic proteins and the major lipid disaturated phosphatidylcholine (DSPC). We investigated how TNF-alpha might alter DSPC content in rat lungs by instilling the cytokine (2.5 microg) intratracheally for 10 min and then assaying parameters of DSPC synthesis and degradation in alveolar type II epithelial cells, which produce surfactant. Cells isolated from rats given TNF-alpha had 26% lower levels of phosphatidylcholine compared with control. TNF-alpha treatment also decreased the ability of these cells to incorporate [(3)H]choline into DSPC by 45% compared with control isolates. There were no significant differences in the levels of choline substrate or choline transport between the groups. However, TNF-alpha produced a 64% decrease in the activity of cytidylyltransferase, the rate-regulatory enzyme required for DSPC synthesis. TNF-alpha administration in vivo also tended to stimulate phospholipase A(2) activity, but it did not alter other parameters for DSPC degradation such as activities for phosphatidylcholine-specific phospholipase C or phospholipase D. These observations indicate that TNF-alpha decreases the levels of surfactant lipid by decreasing the activity of a key enzyme involved in surfactant lipid synthesis. The results do not exclude stimulatory effects of the cytokine on phosphatidylcholine breakdown.     

Effect of nickel(II) chloride on iron content in rat organs after oral administration

The effect of oral administration of nickel(II) chloride on iron content in serum and certain body organs of rats was investigated. The male adult rats were given 300 and 1200 ppm Ni in drinking water for 90 d. The iron content in serum, liver, kidney, lung, spleen, and brain was analyzed 30 and 90 d postexposure. The hemoglobin, hematocrit, and body and organ weights were also measured. Nickel given in drinking water led to a pronounced increase in iron content in serum and the liver, as compared to control rats. This effect was related to Ni concentration in the water. There was not great time-dependent difference in the iron content as a response to continuous nickel treatment, except the lung of 1200-ppm Ni-treated rats. In relation to hematological parameters, Ni supplementation did not affect any of them. Body weight significantly decreased, and lung weight was significantly increased in 1200-ppm Ni-treated rats. The results of this study indicate that nickel ingestion (300 and 1200 ppm in the drinking water) induces the iron uptake by serum and some organs of rats. The highest amount of iron was found in the liver of all exposed animals, and the time-dependent difference in iron content was observed in the lung of 1200-ppm Ni-treated rats.     

Acute effects of intratracheal administration of platelet-activating factor in baboons

The bronchomotor effect of intratracheal administration of PAF-acether (60 micrograms X kg -1) was investigated in 37 curarized baboons mechanically ventilated with constant volume and frequency. PAF-acether caused an immediate bronchoconstriction as assessed by a marked increase in peak inspiratory pressure with no change in static pulmonary compliance and chest X-rays. There was a concomitant fall in arterial PO2 and a significant increase in ventilated unperfused lung zones. A decrease of circulating platelets and leucocytes was also observed. Local anesthesia with lidocaine and atropine did not prevent PAF-acether-induced bronchoconstriction although both markedly reduced the bronchial response to histamine. Albuterol significantly reduced the bronchial response to PAF-acether. Pretreatment with aspirin (80 mg X kg -1 iv) did not prevent the bronchoconstriction caused by PAF-acether, and intravenous or intratracheal arachidonic acid caused no bronchial response. Thus the role of cyclooxygenase metabolites of arachidonic acid in PAF-acether-induced bronchoconstriction is unlikely. In conclusion, an acute bronchoconstriction probably not triggered by stimulation of irritant receptors of the airways and associated with aggregation of platelet takes place subsequent to intratracheal administration of PAF-acether. These data suggest that PAF-acether might play a role in the pathogenesis of human asthma.     

Effects of intratracheal administration of nuclear factor-kappaB decoy oligodeoxynucleotides on long-term cigarette smoke-induced lung inflammation and pathology in mice

Background

Sildenafil, a potent phosphodiesterase type 5 (PDE5) inhibitor, has been proposed as a treatment for pulmonary arterial hypertension (PAH). The mechanism of its anti-proliferative effect on pulmonary artery smooth muscle cells (PASMC) is unclear. Nuclear translocation of nuclear factor of activated T-cells (NFAT) is thought to be involved in PASMC proliferation and PAH. Increase in cytosolic free [Ca²⁺] ([Ca²⁺]_i) is a prerequisite for NFAT nuclear translocation. Elevated [Ca²⁺]_i in PASMC of PAH patients has been demonstrated through up-regulation of store-operated Ca²⁺ channels (SOC) which is encoded by the transient receptor potential (TRP) channel protein. Thus we investigated if: 1) up-regulation of TRPC1 channel expression which induces enhancement of SOC-mediated Ca²⁺ influx and increase in [Ca²⁺]_i is involved in hypoxia-induced PASMC proliferation; 2) hypoxia-induced promotion of [Ca²⁺]_i leads to nuclear translocation of NFAT and regulates PASMC proliferation and TRPC1 expression; 3) the anti-proliferative effect of sildenafil is mediated by inhibition of this SOC/Ca²⁺/NFAT pathway.

Methods

Human PASMC were cultured under hypoxia (3% O₂) with or without sildenafil treatment for 72 h. Cell number and cell viability were determined with a hemocytometer and MTT assay respectively. [Ca²⁺]_i was measured with a dynamic digital Ca²⁺ imaging system by loading PASMC with fura 2-AM. TRPC1 mRNA and protein level were detected by RT-PCR and Western blotting respectively. Nuclear translocation of NFAT was determined by immunofluoresence microscopy.

Results

Hypoxia induced PASMC proliferation with increases in basal [Ca²⁺]_i and Ca²⁺ entry via SOC (SOCE). These were accompanied by up-regulation of TRPC1 gene and protein expression in PASMC. NFAT nuclear translocation was significantly enhanced by hypoxia, which was dependent on SOCE and sensitive to SOC inhibitor SKF96365 (SKF), as well as cGMP analogue, 8-brom-cGMP. Hypoxia-induced PASMC proliferation and TRPC1 up-regulation were inhibited by SKF and NFAT blocker (VIVIT and Cyclosporin A). Sildenafil treatment ameliorated hypoxia-induced PASMC proliferation and attenuated hypoxia-induced enhancement of basal [Ca²⁺]_i, SOCE, up-regulation of TRPC1 expression, and NFAT nuclear translocation.

Conclusion

The SOC/Ca²⁺/NFAT pathway is, at least in part, a downstream mediator for the anti-proliferative effect of sildenafil, and may have therapeutic potential for PAH treatment.     

Mechanism of prolonged hypocoagulation appearing after intratracheal administration of heparin]

The comparative study of intratracheal and intravenous effect of administration of heparin on blood clotting and mast cell population condition was carried out in experiments. Unlike intravenous bolus injection of heparin, which induced fast short-time inactivation of all enzyme clotting factors, a single intratracheal injection inactivated "internal" rout of thrombin production. It was shown, that long-term hypocoagulability effect and inhibition of factors of blood coagulation after intratracheal administration of heparin correlated with accumulation of heparin in mast cell.     

Quantitative patterns of a model of intratracheal administration in an experiment

The distribution of 239PuO2 (241Am) and BeO (7BeO) within the lungs of rats and dogs after the intratracheal administration was found to follow a normal law. The amplitude of deposition variations reached 98 per cent of the amount administered. It is recommended to group the experimental animals by individual deposition estimates.     

一种有效的小鼠气道内siRNA给药方式模型建立

目的建立一种有效的哮喘小鼠气道内siRNA给药方式。方法雌性BALB／c小鼠以卵蛋白致敏法建立哮喘小鼠模型后,以NF-κB（p50）基因为靶基因,通过自制雾化器分别将NF-κB siRNA（20μmol／L,100μL／只）溶液及相同浓度的非干扰siRNA溶液分别雾化注射入实验组和对照组小鼠气道内。给药后,处死小鼠取肺组织,通过荧光定量PCR检测NF-κB基因表达变化,确定该给药方式的有效性。结果通过直接气道内雾化给药的方式能显著降低NF—KB基因表达水平（NF-κB下调1．743倍,P=0．0035）。结论采用气道直接雾化给药的方法能有效降低靶基因的表达。     

Reflex responses to capsaicin: intravenous, aerosol, and intratracheal administration

Intravenous capsaicin elicits the "pulmonary chemoreflex" (apnea, bradycardia, and hypotension) presumably through the stimulation of "pulmonary C-fibers." The present study was designed to ascertain whether tracheobronchial C-fibers play a role in the above reflex response. We compared the effects of capsaicin injected intravenously, administered as an aerosol, and administered topically into the intrathoracic trachea in anesthetized dogs (n = 17) and rats (n = 17). We measured esophageal, subglottic, and arterial pressures together with abdominal muscle electromyogram. Changes in expiratory duration [(TE), measured as the ratio TEtest to TEcontrol, mean +/- SD] due to capsaicin were similar with all three routes of administration in both dogs (intravenous, 7.9 +/- 4.6; aerosol, 5.5 +/- 3.1; topically into intrathoracic trachea, 7.1 +/- 4.8) and rats (intravenous, 22.6 +/- 10.3; aerosol, 11.1 +/- 8.2; topically into intrathoracic trachea, 21.6 +/- 4.6). An increase in laryngeal resistance was a constant finding in the rat, but it was less frequent in the dog. Cardiovascular responses consisting of bradycardia and hypotension occurred with all three routes of administration but had longer delays than the respiratory responses. Capsaicin instillation into the extrathoracic trachea in dogs (n = 7) also induced qualitatively similar cardiorespiratory responses. We conclude that 1) capsaicin-sensitive receptors are accessible from both the pulmonary circulation and the airway lumen and 2) afferents, even in the extrapulmonary portion of the tracheobronchial tree, can play a role in the reflex responses to intraluminal capsaicin.