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Five Steps in Leukocyte Extravasation in the Rnicrocirculation by Chemoattractants

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Five Steps in Leukocyte Extravasation in the Rnicrocirculation by Chemoattractants Research Paper Mediators of Inflammation 1, 403-409 (1992) FOR in vivo study of the phenomena observed in vitro, Five steps in leukocyte PMN (polymorphonuclear leukocyte) extravasation was analysed quantitatively in the microcirculation of the extravasation in the hamster cheek pouch using a video system. Topical rnicrocirculation by application of leukotriene B or N-formyl-methionyl- leucyl-phenylalanine increased dose dependently the chemoattractants number of PMNs adhering to the venules. Eighty to 90% of the adhering PMNs disappeared from the vascular lumen into the venular wall within 10-12 rain after the T. Oda, *'1, M. Katori,1cA adhesion. After PMNs had passed through the endothelial K. Hatanaka and S. Yamashina 2 cell layer, they remained in the venular wall for more than 30 min after application of the chemoattractants and appeared in the extravascular space. Thus, the process 1Department of Pharmacology and 2Anatomy, could be divided into five steps: (1) rolling and (2) Kitasato University School of Medicine, adhesion to the endothelium, (3) passage through the Sagamihara, Kanagawa 228, Japan, endothelial layer (4) remaining in the venular wall, and *Present Address: Department of Biology, (5) passage through the basement membrane. Faculty of General Education, Yamagata University, Yamagata 990, Japan Key words: fMLP, LTB4, Neutrophil adhesion, Neutrophil extravasation, Vascular basement membrane CA Corresponding Author Introduction In spite of the extensive efforts made in adhesion molecules in vitro, in order to of leuko- examining Transmigration polymorphonuclear understand properly the phenomenon of neutrophil cytes from the circulation to the (PMNs) extravasation, which occurs in vivo at the micro- extravascular is one of the cardinal of space signs circulatory level, confirmation in vivo of the in vitro the acute inflammatory responses. At the micro- findings is essential. Also, in order to discuss PMN level, PMNs have been described as circulatory at the molecular level in vivo, the venular wall 1'2 and then transmigration rolling along adhering quantitative analyses are required. to the inner surface of the endothelial cells. 1'3-s We reported a quantitative analysis of the rolling Studies electron have also indicated by micrography and adhesion of PMNs induced by leukotriene (LT) that PMNs the vessel wall between penetrate B and N-formyl-methionyl-leucyl-phenylalanine endothelial cells. 6- However, observations, 4 past (fMLP) in the microcirculation of the hamster cheek made in vivo at the microcirculatory level, of the pouch. The behaviour of PMNs in the vascular process of transmigration of PMNs have been lumen was quantified from changes in intensity of mainly rather descriptive, and not quantitative. images transmitted from a monochrome television The initial report from in vitro experiments that camera to a TV monitor screen, by using a incubation of interleukin-1 with cultured en- (TV) on this screen, but the dothelial cells from the human umbilical vein photocell placed subsequent steps of PMN extravasation remain to be analysed. increased their adhesivity for neutrophils1 stimu- The present experiments aim to give a lated studies on adhesion molecules. Since then, quantitative analysis of the entire process of the many findings on adhesion molecules of neutrophils transmigration of PMNs from the bloodstream to and endothelial cells have been accumulated using the perivascular space at microcirculatory levels in cultured endothelial cells and isolated neu- the cheek pouch of anaesthetized hamsters. trophils. 12'13 Two intercellular adhesion molecules, ICAM-1 (intercellular adhesion molecules-I) 14 and s ICAM-2 have been identified on endothelial cells Materials and Methods in relation to neutrophil adhesion to these cells. Simultaneously, studies of patients who show Preparation of hamster cheek pouch: The hamster cheek repetitive infection and lack of PMN migration16 pouch preparations were set up as previously have revealed congenital deficiencies of a family of described. 3's'18 Tracheal intubation ensured spon- surface glycoproteins of leukocytes, which have taneous respiration. The male golden hamsters now been identified as adhesion molecules of the (Mesocricetus auratus, 120-150 g, 10-16 weeks old) integrin superfamily (CD11/CD18). 17 were anaesthetized with pentobarbital (Nembutal (R), (C) 1992 Rapid Communications of Oxford Ltd Mediators of Inflammation. Vol 1992 403 T. Oda et al. Abbot Lab, Chicago, IL, USA) (60 mg/kg, i.p.). citrate, and observed by a JEM-1200EX electron The cheek pouch was everted, cut longitudinally, microscope (JEOL Ltd, Tokyo). and extended. The avascular connective tissue was elaborately dissected away to expose the micro- Results vasculature of the mucous layer. The thin mucous membrane tissue was spread in a plastic chamber Rolling: In the absence of chemoattractants, a few (9 ml) and superfused at 5 ml/min with warmed PMNs could be individually visualized as bright Tyrode's solution, which was maintained at 37C. white ceils against the dark background of the Body temperature was maintained with a warming blood stream, since they rolled slowly on the pad positioned directly beneath the hamster and endothelial wall. Although the number of rolling maintained at 37C. PMNs was quite variable from preparation to preparation, the majority of the rolling observation and behaviour" Microscopic recording of leukocyte PMNs moved in a jerky fashion, then came to rest The microvasculature of the hamster cheek pouch suddenly for short, but variable periods of time was observed with transillumination under a (3--30 s), and finally returned to the bloodstream Co. microscope (BHA, Olympus Optical Ltd, (Fig. 1). The behaviour of a PMN moving slowly a water immersion lens and Tokyo), using ( 40) along the endothelial surface and stopping at the x 10 eyepieces (Olympus Optical Co. Ltd, Tokyo). same site for less than one minute was designated of the microcirculation were into Images projected as 'rolling'. Some PMNs rested at the same site for a TV monitor screen via a monochrone TV camera longer periods, but eventually they moved again (CTC 2600, Ikegami Tsushinki, Tokyo) mounted at (Fig. 2). the a top of triocular microscope. The leukocyte On the application of a chemoattractant (either responses in each experiment were usually recorded LTB4 or fMLP) the number of rolling PMNs was with a recoder videotape (VO-5850, Sony Co., kept constantly low and was not increased (Fig. 2), Tokyo) and replayed after the experiments. The rolling behaviour, adhesion to the vessel walls, and 50 migration to the extravascular space, of individual Tyrode 50 #1 (n:5) .E F'-I leukocytes were clearly visible on the screen. The LTB4 0.15 pmol/50 lal (n:5) observation and were o 40 experimental procedures LTB4 1.5pmol/5011 (n:6) performed only once for each animal. The Z LTB4 15 pmol/50 #1 (n:6) behaviour of individual leukocytes in a post- N 3O capillary venule of 13-15 #m diameter were observed over a 110/m length along a venule. 20 the 30 min During equilibration period, margina- o lO tlng leukocytes could be visualized inside the o venules as they rolled along the endothelium at a Z o lower velocity than the bulk flow. 3-30 30-60 60 sec- Chemotactic agents: LTB4 (Paesel, Gmbh and Co, Resting time (s) Frankfurt) and fMLP (Peptide Institute, Minoh, Osaka) were used as chemoattractants. Stock 50 solutions of LTB4 (30/M in absolute ethanol) or F--I Tyrode 50 ILtl (n:5) at fMLP (1 mM in saline) were kept frozen --70C fMLP (n:5) E 40 nmol/5OiLtl and diluted to appropriate concentrations with o fMLP 3nmol/5OiLtl (n:5) Tyrode's solution immediately before use. z 3o fMLP 10 nmol/50 pl (n:5) Application of LTB4 and fMLP: The superfusion of the cheek pouch with Tyrode's solution was .E 20 stopped during the experiments. LTB4 or fMLP solution was applied to the microvasculature at the o lO observation sites with a 50/1 micropipette. d 0 Electron microscopy: Before and 30 min after the 3-30 30-60 60 sec- application of LTB4, parts of the thin preparation Resting time (s) of the hamster cheek pouch used for examination FIG. 1. Times for which PMNs remained at the same site in a venule after of the microcirculation were fixed in topical application of LTB4 and fM LP. The abscissa indicates the ranges 2.5% of time spent by the same PMNs at the same site on the inner surface of glutaraldehyde and 1% osmium tetroxide. Ultra- the venules. The ordinate indicates the cumulative numbers of PMNs thin sections were cut on a LKB ultramicrotome remaining for each time range, counted in a 110 Fm length along a venule on the monitor screen for 50 min after the application of LTB4 or fMLP. and were stained with uranyl acetate and lead Values indicate the mean (_+ SE) from five to six animals. 404 Mediators of Inflammation. Vol 1992 Five steps in leukocyte extravasation O Tyrode 50 Id O Tyrode 50 1 (n:5) I LTB 0.15 pmol/50pl (n:5) 1 LTB4 0.15 pmol/50 d (n:5) 4O [] LTB4 1.5 pmol/50 Ill (n:6) .E [] LTBa 1,5 pmol/50 pl LTB4 15pmol/501d (n:6) E (hi6) . 3o 20 d 0 0 10 20 30 40 50 --5 0 10 20 30 40 50 Min Min O Tyrode 50 pl (n:5) O Tyrode 50 d (n:5) fMLP nmol/50d (n:5) fMLP nmol/50 pl (n:5) 4O [] fMLP 3nmol/50pl (n:5) .:_ fMLP nmol/50 pl fMLP 10 nmol/50 pl (n:5) E (ni5) .: 30 20 6 0 -5 0 10 20 30 40 50 Min --5 0 10 20 30 40 50 Min FIG. 3. Changes in the numbers of adhering PMNs after LTB4 and fMLP. The abscissa indicates the time lapse after LTB4 or fMLP application FIG.
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