Responsiveness of individual airways to methacholine in adult rat lung explants

122

125

To study the role of small airways in the early allergic response (EAR), the method of human precision-cut lung slices (PCLS) was developed and used to examine the bronchoconstriction elicited by passive sensitisation and allergen provocation.Viable human PCLS of 250-mm thickness containing airways v1.5 mm in outer diameter were prepared from lung lobes obtained from lung resection and taken into culture. According to the low release of lactate dehydrogenase and the constant ciliary beat frequency, human PCLS were viable for at least 3 days.Following overnight passive sensitisation with serum from allergic individuals, administration of grass-pollen extract or activating immunoglobulin E antibody resulted in immediate airway contraction that was quantified by videomicroscopy. The extent of the EAR increased with decreasing airway size (outer airway diameter), with the strongest response occurring in the terminal bronchioles.Histamine receptor antagonism was ineffective, and leukotriene or thromboxane receptor antagonism attenuated the early allergic response only in some cases. However, simultaneous blockade of leukotriene and thromboxane receptors almost completely prevented the early allergic response in the precision-cut lung slices from all individuals, suggesting such a dual treatment as a potential future asthma therapy.

Section: The Model Of Precision-cut Lung Slicesmentioning

confidence: 99%

The early allergic response in small airways of human precision-cut lung slices

Wohlsen

Martin²,

Vollmer³

et al. 2003

122

125

“…Lung explants were prepared according to a modification [14] of the method of DANDURAND et al [13] which is presented here in brief. Using sterile technique, the lungs were removed from the chest cavity, the heart dissected free, and a 14-gauge catheter inserted into the trachea.…”

Section: Explant Preparation and Exposurementioning

confidence: 99%

“…As DANDURAND et al [13] have previously shown that the degree of inter-animal variability in airway responsiveness is less than intra-animal variability, and it has been demonstrated that intra-animal variability depends largely on airway size [14], all of the explants in each group were pooled. Explants from smoke-exposed and control rats were then randomly divided into six groups; the explants in each of the tests were incubated in medium plus supplement, as indicated below, for 30 min.…”

Section: Explant Preparation and Exposurementioning

confidence: 99%

“…Lung explants have proven to be an excellent vehicle by which to study directly the effects of constrictor agents on the peripheral airways [13,14] in an environment which is free of the complicating effects of inflammatory cells and circulating mediators. In this study, the explant technique has been utilized to examine the possible direct smooth muscle constrictor effects of smoke on the noncartilaginous (peripheral) airways.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Cigarette smoke exposure causes constriction of rat lung

Wright

Sun²,

Churg³

1999

Cigarette smoke exposure causes constriction of rat lung explant airways. JL. Wright, J-P. Sun, A. Churg. # ERS Journals Ltd 1999. ABSTRACT: Cigarette smoke is known to cause acute increases in airway resistance, but the mechanisms behind this effect are unknown.Lung explants were utilized to examine the constrictive effects of acute cigarette smoke exposure on bronchioles from rats in vitro that had or had not been previously exposed to cigarette smoke in vivo.It was found that smoke induced a small but consistent degree of contraction of the airways in vitro, which could be reduced by an endothelin receptor antagonist in the animals which had had no previous smoke exposure in vivo, and reduced by the oxidant scavengers superoxide dismutase or catalase in the animals with previous smoke exposure.In conclusion, cigarette smoke induces acute small airways constriction through both endothelin release and direct oxidant effects; which mechanisms are operative depends on the prior smoking status.

“…DANDURAND et al [7] have recently demonstrated the principal applicability of lung slices to study airway constriction. With lung slices, constriction of airways can be observed directly under a microscope.…”

mentioning

confidence: 99%

Videomicroscopy of methacholine-induced contraction of individual airways in precision-cut lung slices

Martin¹,

Uhlig²,

Ullrich³

1996

150

187

V Vi id de eo om mi ic cr ro os sc co op py y o of f m me et th ha ac ch ho ol li in ne e--i in nd du uc ce ed d c co on nt tr ra ac ct ti io on n o of f i in nd di iv vi id d--u ua al l a ai ir rw wa ay ys s i in n p pr re ec ci is si io on n--c cu ut t l lu un ng g s sl li ic ce es s Lung slices of 250±20 µm were prepared from Wistar rats and cultured in a roller incubator in serum-free minimum essential medium (MEM). Under these conditions, the slices were viable for at least 70 h, as indicated by leakage of lactate dehydrogenase into the supernatant, thymidine incorporation and ciliary beating. The slices were placed in a newly developed incubation chamber and mounted by a nylon thread that was fixed to a platinum wire. The whole chamber was positioned on a microscope stage, and contraction of single airways was followed under a microscope that was coupled to a CCD-camera. Reduction in airway area was taken as an index of bronchoconstriction and was determined by a computer program.Addition of methacholine resulted in a concentration-dependent (concentration producing half the maximal effect (EC50)=0.64±0.08 (mean±SD) µM; n=64) contraction of single airways. In the presence of hydrocortisone, the EC50 was about six times greater, i.e. 3.7±0.9 µM (n=7), and the effect of the steroid was largely abolished by propanolol (EC50=1.1±0.1 µM; n=7). Airways with an area smaller than 35,000 µm 2 were nearly nine times more sensitive to methacholine (EC50=0.1±0.03 µM; n=20) than larger ones (EC50=87±0.27 µM; n=22).We conclude that cultured precision-cut lung slices are a useful model for routine study of contraction of individual airways of various sizes. The measurements were precise and reproducible and showed that smaller airways are more sensitive to methacholine than larger ones.