Rat CINC, a member of the interleukin-8 family, is a neutrophil-specific chemoattractant in vivo

Rat cytokine-induced neutrophil chemoattractant (CINC) is a member of the IL-8 family and its human counterpart is MGSA/gro. Rat neutrophil responses in vitro to rat CINC, human IL-8, and human MGSA/gro were studied. CINC concentrations as low as 1 nM induced apparent chemotaxis of rat neutrophils, but human IL-8 and MGSA/gro required concentrations one or two orders higher than that of CINC to attract neutrophils. These data indicate that human IL-8 and MGSA/gro cannot sufficiently substitute for rat counterparts such as CINC in rats. Therefore, the effect of rat CINC on rats was studied. Intradermally injected 10(-10)-10(-7) M CINC dose-dependently caused infiltration of neutrophils. Significant migration of neutrophils appeared by 30 min, and maximum infiltration was observed around 1-2 hr after the injection. CINC induced quick and transient neutrophil accumulation without lymphocyte and monocyte migration or edema formation. CINC, a member of the IL-8 family but a counterpart of human MGSA/gro-related proteins, is a specific neutrophil chemoattractant and can be distinguished from IL-8, which is a chemotactic factor for lymphocytes and neutrophils.     

Induction of neutrophil infiltration by rat chemotactic cytokine (CINC) and its inhibition by dexamethasone in rats

In vivo effects of cytokine-induced neutrophil chemotactic factor (CINC) derived from rats on neutrophil infiltration were investigated using an air-pouch-type inflammation model in rats, and effects of dexamethasone on neutrophil infiltration induced by CINC was also examined in order to gain further insight into the mechanism of antiinflammutory activity of glucocorticoids. Injection of CINC into the air pouch made on the dorsum of rats induced a marked infiltration of neutrophils into the pouch fluid but not mononuclear cells and eosinophils during a 30-min interval after the injection. Maximum effect was induced at a dose of 1.4g/pouch. Treatment with dexamethasone 3 h before the injection of CINC suppressed the neutrophil infiltration in a dose-dependent manner, but no complete inhibition was observed. CINC injection into the air pouch of rats that had been sacrificed by bleeding in order to minimize neutroph il infiltration from blood stream also stimulated neutrophil infiltration into the pouch fluid when the carcass was incubated at 37C for 30 min, but the number of infiltrated neutrophils was about 35% of CINC-induced neutrophil infiltration in intact ruts. CINC-induced neutrophil infiltration in the carcass, which is supposed to be a reflection of neutrophil migration from extravascular space in subcutaneous tissues to pouch fluid, was not inhibited by dexamethasone treatment. Therefore, the inhibition of neutrophil infiltration by dexamethasone might be due to inhibition of the extravasation of peripheral neutrophils but not due to inhibition of neutrophil chemotaxis from subcutaneous extravascular space to pouch fluid. These findings suggest that clinical effects of steroidal antiinflammatory drugs on neutrophil infiltration in inflammatory disease is partly due to inhibition of neutrophil extravasation induced by preformed neutrophil chemotactic factors in the inflammatory site.     

Effect of rat CINC/gro, a member of the interleukin-8 family, on leukocytes in microcirculation of the rat mesentery.

Rat cytokine-induced neutrophil chemoattractant (CINC) is a member of the IL-8 family, and its human counterpart is gro/MGSA but not IL-8. We ascertained that chemically synthesized CINC was comparable to native CINC/gro with regard to chemotactic activity for rat neutrophils and studied the effect of synthesized CINC/gro on circulating leukocytes in microvascular vessels of rat mesentery. Exposure of rat mesentery to 10(-8)M authentic CINC/gro induced neutrophil adherence to and extravasation from postcapillary venules (PCVs) but not from capillaries or arterioles. CINC/gro concentrations as low as 10(-10) M were effective in causing neutrophil adherence. Neutrophils adhered to thin PCVs (mean diameter, approximately 25 microns) after exposure to CINC/gro for 15 min. The mean diameters of the PCV with adherence of neutrophils after exposure to CINC/gro for 30 and 60 min were 37 and 43 microns, respectively. The diameters of PCV with extravasation of neutrophils also increased in a time-dependent manner. The starting position of adherence of neutrophils was approximately 25-50 microns away from the upper junction of two vessels and remained virtually unchanged during exposure to CINC/gro for 60 min. However, the distance from the start to the end of neutrophil adherence increased in a time-dependent manner. The effect of CINC/gro on adherence and extravasation of leukocytes was neutrophil specific since other leukocytes such as lymphocytes and monocytes were not identified among the adherent and extravasated leukocytes.     

Contribution of cytokine-induced neutrophil chemoattractant CINC-2 and CINC-3 to neutrophil recruitment in lipopolysaccharide-induced inflammation in rats

OBJECTIVE: We have estimated the contribution of three types of cytokine-induced neutrophil chemoattractants (CINC-1, -2 and -3) and rat macrophage inflammatory protein (MIP)-1alpha to neutrophil recruitment in the air pouch/ lipopolysaccharide (LPS)-induced inflammation in rats. MATERIALS AND METHODS: Excess amounts of anti-CINC-2, CINC-3 and MIP-1alpha antibodies (Abs), together with LPS (1 microg/ml), were injected into the preformed air pouch of rats. Chemokine levels and chemotactic activity in the pouch fluid were measured using enzyme-linked immunosorbent assay and multiwell-type Boyden chambers in vitro, respectively. RESULTS: Excess amounts of the Abs significantly neutralized CINC-1 and almost completely neutralized CINC-2, CINC-3 and MIP-1 alpha in the pouch fluid, and a significant suppression (about 60% inhibition) of neutrophil infiltration by the Abs was found. In agreement with the in vivo results, in vitro neutralization experiments demonstrated that complete neutralization of CINCs and MIP-1alpha by the Abs resulted in a marked suppression (73% inhibition) of chemotactic potency of 8-h pouch fluid (exudate) from LPS-treated rats. On the other hand, treatment with anti-CINC-2, CINC-3 or MIP-1alpha Ab alone resulted in 48%, 34% or 10% inhibition, respectively, of chemotactic activity of the 8-h exudate. CONCLUSIONS: Our results suggest that CINC-2, a novel rat CXC chemokine and CINC-3 play an important role in neutrophil recruitment in the rat air pouch/LPS-induced inflammation.     

Characterization of methylated bovine serum albumin-induced allergic inflammation in rats.

An air pouch type allergic inflammation in rats was induced using an insoluble cationic protein, methylated bovine serum albumin (MeBSA), as an antigen. Changes in vascular permeability, local tissue edema, histamine contents in the pouch fluid, and number of infiltrated leukocytes and chemotactic activity in the pouch fluid were analyzed during an 8-hour period after injecting the antigen solution into the air pouch of the immunized and nonimmunized rats. Vascular permeability during the first 30-min interval in the immunized rats was higher than that in the nonimmunized rats, reflecting a higher histamine level in the pouch fluid. However, both the increase in vascular permeability and histamine level in the immunized rats in this period were much lower than those induced by a soluble, noncationic antigen, azobenzenearsonate-conjugated acetyl bovine serum albumin. In the MeBSA-induced allergic inflammation model, a second peak of vascular permeability was induced at 2 h, and local tissue edema formation became apparent at 2 h, reaching a plateau at 4 h. A prominent increase in leukocyte infiltration, especially neutrophils, into the pouch fluid was induced at 4 h in accordance with an increase in chemotactic activity in the pouch fluid. These observations indicate that the acute phase of MeBSA-induced allergic inflammation is characterized by a weak anaphylactic response and a prominent neutrophil infiltration.     

Leukocyte-Derived Neutrophil Chemotactic Factor-2 Produced by Infiltrated Leukocytes in Allergic Inflammation Model in Rats is Macrophage Inflammatory Protein-2

In the air pouch-type allergic inflammation model in rats, leukocytes collected from the pouch fluid 4 h after the antigen challenge produced proteinaceous chemotactic factors for neutrophils. The leukocytes from the immunized rats produced significantly higher amount of the chemotactic factors than that from the non-immunized rats. The major chemotactic factor, leukocyte-derived neutrophil chemotactic factor (LDNCF)-2, was purified and found to be identical with rat macrophage inflammatory protein (MIP)-2 by N-terminal amino acid sequence analysis. Expression of MIP-2 mRNA was higher in the leukocytes from the immunized rats than that from the non-immunized rats. Possible roles of LDNCF-2 (MIP-2) in neutrophil infiltration in the allergic inflammation is discussed.     

Leukocyte-Derived Neutrophil Chemotactic Factor-2 Produced by Infiltrated Leukocytes in Allergic Inflammation Model in Rats is Macrophage Inflammatory Protein-2

In the air pouch-type allergic inflammation model in rats, leukocytes collected from the pouch fluid 4 h after the antigen challenge produced proteinaceous chemotactic factors for neutrophils. The leukocytes from the immunized rats produced significantly higher amount of the chemotactic factors than that from the non-immunized rats. The major chemotactic factor, leukocyte-derived neutrophil chemotactic factor (LDNCF)-2, was purified and found to be identical with rat macrophage inflammatory protein (MIP)-2 by N-terminal amino acid sequence analysis. Expression of MIP-2 mRNA was higher in the leukocytes from the immunized rats than that from the non-immunized rats. Possible roles of LDNCF-2 (MIP-2) in neutrophil infiltration in the allergic inflammation is discussed.     

Morphological Alteration of Cultured Tracheobronchial Epithelial Cells is Accompanied by the Expression of Chemokines, MCP-1 and CINC/gro, in Rats

Morphologically altered epithelial cells are generally observed in fibrotic lung conditions and have been reported to produce several cytokines. To examine the relationship between morphological changes of the tracheobronchial epithelial cells (TBECs) and their chemokine production, we investigated, (1) the mRNA expression and protein secretion of monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant/gro (CINC/gro), (2) morphological changes by electron microscopy, and (3) cytokeratin (CK) expression, using a primary culture system of rat TBECs. The constitutive secretion of MCP-1 in the culture supernatant of TBECs increased in a time-dependent manner, whereas the CINC/gro secretion was not changed. These results were consistent with the chemokines'' mRNA expression observed by in situ hybridization. The constitutive secretions of MCP-1 and CINC/gro were inhibited partially but significantly by dexamethasone. With the extension of the culture period, the morphology of the TBECs became flat and spindle in shape, similar to squamous metaplasia, as observed on electron microscopy, and with strong expression of CK 14. Sequential staining using immunocytochemistry and in situ hybridization revealed the coexpression of MCP-1 mRNA and CK 14. These data indicate a significant relationship between the morphological squamoid alteration and the constitutive expression of MCP-1 but not of CINC/gro. It is thought that the squamous metaplasia of TBECs may accompany the alteration of cytokine production and play an important role in chronic lung inflammation.     

Interleukin-1 stimulates rapid release of cytokine-induced neutrophil chemoattractant (CINC) in rat lungs

We found that intratracheal insufflation of interleukin-1 (IL-1) in rats rapidly increased lung lavage cytokine-induced neutrophil chemoattractant (CINC) concentrations, lung tissue myeloperoxidase (MPO) activity, and lung lavage neutrophil counts, and that CINC elevation preceded the migration of neutrophils into the lung. Further, we found that bolus CINC insufflation increased CINC concentrations in plasma, and we found that alveolar macrophages (AM) in lung tissue selections or AM recovered by lavage from rats given IL-1 intratracheally stained positively for CINC by immunohistochemistry. In addition, incubating rat AM with increasing doses of IL-1 in vitro progressively increased CINC concentrations in the culture medium. Our results suggest that the potent neutrophil chemoattractant CINC is rapidly produced and released by rat AM following challenge with IL-1 in vivo or in vitro, and support the hypothesis that CINC is an important mediator in the development of pulmonary inflammation in the rat.Parker B. Francis Fellow in Pulmonary Research.     

Prophylactic effect of JTE-607 on LPS-induced acute lung injury in rats with CINC-1 inhibition

OBJECTIVE AND DESIGN: JTE-607, a multiple cytokine inhibitor, was evaluated in lipopolysaccharide (LPS)-induced acute lung injury in rats in vivo and in vitro. MATERIALS AND METHODS: LPS instillation into airways of rats was performed. JTE-607 at 3-30 mg/kg and dexamethasone at 3 mg/kg were administered intravenously at 10 min and 0 min for JTE-607, and 60 min for dexamethasone prior to the LPS instillation (n = 8). Cytokine-induced neutrophil chemoattractant (CINC)-1 level and myeloperoxidase (MPO) activity in lung were measured at 4 h after LPS instillation, and at 24 h for lung wet weight measurement and histological study. LPS-induced CINC-1 production by rat alveolar macrophages were also measured in vitro. RESULTS: JTE-607 and dexamethasone showed a significant reduction of increased CINC-1 level and MPO activity in lung after LPS treatment in vivo. Increased wet weight was also significantly inhibited. Histological studies revealed that JTE-607 and dexamethasone significantly inhibited LPS-induced accumulation of peribronchial neutrophils and eosinophils, and perivascular edema. JTE-607 and dexamethasone suppressed CfNC-1 synthesis by rat alveolar macrophages in vitro with IC50 values of 12.4 microM and 2.3 nM, respectively. CONCLUSIONS: These results indicate that JTE-607 has an inhibitory effect on LPS-induced rat lung inflammation in parallel with CINC-1 reduction. The effect of JTE-607 was suggested to be through direct inhibition of CINC-1 production from rat alveolar macrophages. JTE-607 may thus be efficacious in cytokine-mediated lung inflammation such as acute respiratory distress syndrome.     

CXCL1/KC and CXCL5/LIX are selectively produced by corneal fibroblasts and mediate neutrophil infiltration to the corneal stroma in LPS keratitis

The severity of corneal inflammation depends on the activity of infiltrating neutrophils responding to chemotactic factors such as CXC chemokines. This study examines the relative contribution of CXCL1/keratinocyte-derived chemokine (KC), CXCL2/monocyte-inhibitory protein-2 (MIP-2), and CXCL5/LPS-induced chemokine (LIX) in neutrophil recruitment to the corneal stroma during LPS keratitis, where neutrophils infiltrate the corneal stroma at 6 h after LPS injection and peak at 24 h. Consistent with this timeframe, KC was detected after 3 h, reached peak levels at 24 h, and decreased thereafter. In contrast, LIX production was not detected until 8 h after injection and peaked at 24 h. MIP-2 was detected at 3 h but did not reach the levels of KC and LIX. Cell types associated with corneal inflammation produced markedly different chemokines in vitro: Murine corneal fibroblasts (MK/T-1) produced LIX and KC in response to LPS but did not produce MIP-2, whereas peritoneal macrophages and neutrophils produced MIP-2 and KC but did not produce LIX. To determine the role of these chemokines in neutrophil recruitment to the cornea, anti-LIX, anti-KC, or anti-MIP-2 was injected into the corneal stroma of enhanced GFP chimeric mice prior to LPS, and total cell and neutrophil infiltration was examined. Antibody to LIX and KC, injected individually or in combination, significantly inhibited neutrophil recruitment to the cornea, whereas anti-MIP-2 had no inhibitory effect. Together, these findings demonstrate cell-specific production of CXC chemokines and show that LIX and KC mediate neutrophil recruitment into the cornea during LPS keratitis.     

Aging Reduces the Expression of Lung CINC and MCP-1 mRNA in a P. aeruginosa Rat Model of Infection

We investigated dynamic changes of inflammatory cell infiltration and expression of cytokine-induced neutrophil chemoattractant (CINC) and monocyte chemoattractant protein-1 (MCP-1) mRNA in aged rats with Pseudomonas aeruginosa pulmonary infection. Disease manifestation and lung tissue pathology (lesion dispersion, inflammatory reactions, tissue edema and bleeding) were more severe in aged rats than young rats. At various time points, lung tissue polymorphonuclear neutrophil and mononuclear macrophage numbers were lower in the aged group than the young group (P < 0.05), and at 24 h there was no difference in mononuclear macrophage numbers. After inoculation with P. aeruginosa, CINC and MCP-1 mRNA expression increased in both groups, but the peak lagged in old rats compared with young. Thus, aging can reduce the expression of CINC and MCP-1 mRNA in lung tissues, and reduce the infiltration of neutrophils and monocyte–macrophages induced by CINC and MCP-1. This might lead to increased risk of pneumonia in elderly patients.     

A Nycodenz gradient method for the purification of neutrophils from the peripheral blood of rats

A Nycodenz gradient technique is described which permits the separation of functionally active polymorphonuclear neutrophils (PMN) from the peripheral blood of rats. PMN are obtained at greater than 90% purity and fractionate at a peak density of 1.0919 g/ml. The method is suitable for isolating PMN when the circulating PMN count is low (less than 20%) as in normal rats and when the count is high (greater than 30%), as a result of inducing inflammation in the subcutaneous air pouch of rats by the intra-pouch injection of peptone. The chemotactic responsiveness of rat PMN was found to be markedly less than that of human PMN when the formyl peptides were used as chemoattractants but not when zymosan-activated serum was the chemoattractant. Blood PMN from normal rats and from peptone-treated rats showed no significant difference in their response to ZAS indicating that priming of their activity by the induction of long term (8 day) inflammation was not a feature of these experiments. However, air pouch-derived PMN displayed a highly significant reduction in activity compared with their isologous blood-PMN. The Nycodenz method offers an alternative to the Percoll separation method for rat blood and will be useful when comparative studies of elicited and non-elicited PMN are required since the latter are obtained in sufficiently high yield and purity for microassays on their function to be performed.     

Possible role for platelet-activating factor in neutrophil infiltration in allergic inflammation in rats

Allergic inflammation was induced by injecting an antigen solution into an air pouch made on the dorsum of immunized rats with the antigen azobenzene-arsonate-conjugated acetyl bovine serum albumin. In this model, leukocyte infiltration into the pouch fluid was prominent 4-8 h after the antigen challenge. Most of the infiltrated leukocytes were neutrophils. Administration of the platelet-activating factor (PAF) antagonists such as CV-3988 and L-652,731 into the air pouch 15 min before and at the time of the antigen challenge failed to suppress leukocyte infiltration at 8 h. However, when the PAF antagonist was injected into an air pouch 4 h after the antigen challenge, neutrophil infiltration at 8 h was suppressed in a dose-dependent manner. Combined treatment with the 5-lipoxygenase inhibitor AA861 and the PAF antagonist did not potentiate the effect of the PAF antagonist, suggesting that participation of leukotriene B4 in neutrophil infiltration in this model is negligible. Eosinophil infiltration was very weak at 8 h, and the PAF antagonist showed no significant effect. At 8 h, the PAF level in the serum of the immunized rats was significantly higher than that of the nonimmunized rats. Intravenous administration of the PAF antagonist 15 min before the antigen challenge suppressed leukocyte infiltration more effectively than local administration into the pouch. These results indicate that PAF plays a significant role in neutrophil infiltration in allergic inflammation.     

Matrix metalloproteinase-8 facilitates neutrophil migration through the corneal stromal matrix by collagen degradation and production of the chemotactic peptide Pro-Gly-Pro

Matrix metalloproteinase (MMP)-8 and MMP-9 play several roles in inflammation, including degradation of extracellular matrix (ECM) components and regulation of cytokine activity. To determine the roles of MMP-8 and MMP-9 in a neutrophil-dependent inflammatory response, we used a murine model of corneal inflammation in which LPS is injected into the corneal stroma. In contrast to wild-type mice, we found that i) lipopolysaccharide (LPS)-injected CXCR2(-/-) corneas had impaired neutrophil infiltration and did not express either MMP-8 or MMP-9; ii) neutrophil migration through the central cornea was impaired in Mmp8(-/-), but not Mmp9(-/-), mice; iii) neutrophil migration was inhibited in collagenase-resistant mice; iv) the chemotactic Pro-Gly-Pro (PGP) tripeptide that binds CXCR2 was decreased in CXCR2(-/-) mice; v) PGP production was impaired in Mmp8(-/-) corneas; and vi) neutralizing anti-PGP antibody did not inhibit neutrophil infiltration in Mmp8(-/-) mice. We found no effects of MMP-8 on LPS-induced CXC chemokine (LIX, or CXCL5)-induced neutrophil recruitment or on LPS-induced CXC chemokine production. Together, these studies indicate that neutrophils contribute to the production of both MMP-8 and MMP-9 in LPS-injected corneas and that MMP-8 regulates neutrophil migration through the dense collagenous ECM of the corneal stroma by generating chemotactic PGP during inflammation.     

Hydroxyethyl starch inhibits NF-kappaB activation and prevents the expression of inflammatory mediators in endotoxic rats

Hydroxyethyl starch (HES) has been shown to be beneficial in several inflammatory situations, but the mechanisms are unclear. The present study tested the hypothesis that HES has effects on nuclear factor kappa B (NF-kappaB) activation and the expression of inflammatory mediators induced by lipopolysaccharide. Sepsis was induced in male Wistar rats by injection of lipopolysaccharide (LPS, 6 mg/kg, i.p.). At 1 min after the LPS challenge, HES was infused via the right external jugular vein at the following doses: 3.75, 7.5, 15, or 30 ml/kg. NF-kappaB activation in peripheral blood mononuclear cells and neutrophils, plasma concentrations of tumor necrosis factor (TNF)-alpha, cytokine-induced neutrophil chemoattractant (CINC), expression of CD11b on the blood neutrophil cell surface, and neutrophil sequestration in multiple organs were examined 2 or 4 hr after the LPS challenge. Treatment of rats with HES (3.75 and 7.5 ml/kg) prevented LPS-induced NF-kappaB activation, and inhibited, in a dose-related manner, LPS-induced TNF-alpha and CINC expression. The 4 graded doses of HES decreased CD11b expression in a dose-dependent manner. HES significantly reduced neutrophil sequestration in lung, heart, and liver. These results suggest that HES has an anti-inflammatory effect in endotoxic rats. This effect is mediated by inhibition in the production pathways for inflammatory mediators, including NF-kappaB activation.     

Stimulatory effect of the herbal medicine Keishi-bukuryo-gan on a cytokine-induced neutrophil chemoattractant, in rat ovarian cell culture

PROBLEM AND METHOD OF STUDY: We investigated the effects of Keishi-bukuryo-gan, a Japanese herbal medicine, and its crude ingredients in relation to the production of cytokine-induced neutrophil chemoattractant (CINC/gro), interleukin 1beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha), which are known to stimulate the secretion of CINC/gro in the ovulatory process, and the effects of Keishi-bukuryo-gan with those of Toki-shakuyaku-san, which has been shown to have an effect on the ovary. We cultured whole ovarian dispersates from immature (3-week-old) female rats with Keishi-bukuryo-gan, Toki-shakuyaku-san and crude ingredients of Keishi-bukuryo-gan. The contents of CINC/gro, IL-1beta and TNFalpha in the cultured media were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: Keishi-bukuryo-gan stimulated the secretion of CINC/gro in a dose-dependent manner, and the secretion of CINC/gro into the culture medium increased significantly at concentrations of Keishi-bukuryo-gan of 10 and 100 microg/mL (P < 0.001). The stimulatory effect of Keishi-bukuryo-gan on the production of CINC/gro is significantly (P < 0.001) stronger than that of Toki-shakuyaku-san at the same concentrations of 100 microg/mL. In addition, Keishi-bukuryo-gan stimulated the secretion of IL-1beta in a dose-dependent manner, while it did not stimulate the secretion of TNFalpha even at a concentration of 100 microg/mL. Moutan Cortex, Paeoniae Radix and Persicae Semen, which are crude ingredients of Keishi-bukuryo-gan, enhanced the secretion of CINC/gro significantly (P < 0.01) in cultured whole ovarian dispersates. CONCLUSIONS: These results show that Keishi-bukuryo-gan can stimulate the secretion of CINC/gro as well as the production of IL-1beta and that this stimulatory effect of Keishi-bukuryo-gan was significantly stronger than that of Toki-shakuyaku-san in immature rat ovarian cell culture.     

Hormonal control of neutrophil chemotactic activity in the rat vagina

A sexual-hormone-dependent neutrophil chemotactic factor(s), operative under physiological conditions, is described. Rat vaginal washouts were shown to be both chemotactic and chemokinetic for rat neutrophils in vitro, whereas macrophages were not attracted. Peak activity was observed at the end of estrus and preceded maximal neutrophil infiltration in the vagina. In order to mimic these events, gonadectomized animals were treated with estradiol for a week. They showed a similar peak of chemotactic activity 30-36 h after estradiol withdrawal, accompanied by a massive neutrophil accumulation. These data suggest that a decrease in estradiol level permits the expression of the chemotactic signal. There was no evidence for chemotaxis and/or migration inhibitors before and during estrus or during long-term estradiol treatment of gonadectomized rats. Induced neutrophil accumulation in the peritoneal cavity and chemotactic responsiveness of these cells in vitro were similar in all stages during the estrus cycle. Estradiol, progesterone, testosterone, and hydrocortisone neither promoted nor significantly inhibited the neutrophil migratory behavior over a wide range of concentrations. Our experiments suggest that the periodic neutrophil accumulation in the rat vagina after estrus is triggered by locally expressed chemotactic mechanisms that are controlled by sexual hormones. The data provide the first evidence that hormonal changes can control chemotactic factors and thus indirectly control cell migration.     

Expression of IL-8 in Kawasaki disease

We investigated, by Northern blotting, ELISA, and a chemotaxis assay, the expression of IL-8 mRNA, the production of IL-8 protein, and the biological activity of mononuclear cells (MNC), polymorphonuclear neutrophils (PMN) and plasma, respectively, from patients with Kawasaki disease (KD) who received intravenous immunoglobulin (IVIG). IL-8 mRNA expression by MNC and PMN, the level of IL-8 protein, and the neutrophil chemoattractant activity within plasma were all increased in the acute phase of KD, and were significantly elevated following IVIG therapy. The level of chemotactic activity of neutrophils, but not that of monocytes, in response to F-met-leu-phe was decreased in patients with KD after IVIG. The increased expression of IL-8 in PMN and MNC, the increased plasma level of IL-8 and the decreased level of neutrophil chemotactic activity of the patients who received IVIG therapy might inhibit the accumulation of neutrophils at the sites of inflammation, and may thus reduce the risk of aneurysm formation.     

Beneficial effects of troglitazone on neutrophil dysfunction in multiple low-dose streptozotocin-induced diabetic mice

Patients with poorly controlled diabetes are at high risk of acquiring bacterial infections. However, conflicting results have been reported on neutrophil function in diabetes. We periodically evaluated neutrophil dysfunction in multiple low-dose streptozotocin (STZ)-induced diabetic mice, and then evaluated the effects of troglitazone and other thiazolidinediones (TZDs) on the decline of neutrophil function. Zymosan was injected intraperitoneally and neutrophil infiltration and phagocytosis were evaluated. While phagocytosis of zymosan by peritoneal neutrophils was consistently reduced in diabetic mice, neutrophil infiltration was decreased on day 30, but increased on day 40 after STZ injection. The in vitro chemotactic and phagocytic activities of blood neutrophils in mice that did not receive zymosan were consistently reduced in diabetic mice. Phorbol myristate acetate (PMA)-stimulated superoxide production by zymosan-induced peritoneal neutrophils and the levels of zymosan-induced tumour necrosis factor (TNF)-alpha and interleukin (IL)-1beta in peritoneal exudate fluids were also reduced in the diabetic mice. Treatment of the diabetic mice with troglitazone beginning 2 weeks after STZ injection did not improve hyperglycaemia but did prevent the decline of zymosan-induced neutrophil infiltration on day 30, and additionally promoted the increased infiltration on day 40. Troglitazone also promoted the chemotactic activity of blood neutrophils isolated from normal mice in vitro. Rosiglitazone but not pioglitazone induced a similar effect. Neutrophil phagocytosis was not enhanced by troglitazone either in vivo or in vitro. Taken together, neutrophil function is impaired by STZ-induced diabetes, but inflammatory infiltration does not always vary with the chemotactic disability or cytokine levels. Furthermore, troglitazone and rosiglitazone were suggested to improve at least neutrophil chemotactic activity in these animals.