title: Effects of angiotensin II on remodelling of the airway and the vasculature in the rat.
abstract: Airway remodelling occurs in chronic asthma. Angiotensin II promotes growth in cardiovascular remodelling. Since the renin-angiotensin system is activated in acute severe asthma, we hypothesized that angiotensin II has a role in airway remodelling. A total of 14 young male Wistar rats were randomly divided into two groups. All received 2-week infusions of bromodeoxyuridine, and the experimental group also received angiotensin II. Blood pressure rose in the angiotensin II-infused group [mean levels: pre-infusion, 134.9 (S.D. 14.7) mmHg; post-infusion, 197.1 (22.5) mmHg], and expression of renin mRNA in the renal juxtaglomerular cells was suppressed in these animals. The proportion of bromodeoxyuridine-positive cell nuclei was no different in the airways of control and angiotensin II-infused animals for smooth muscle [mean bromodeoxyuridine index: control, 8. 6% (S.E.M. 1.1%); angiotensin II, 9.3% (1.1%)], epithelium [control, 16.7% (2.3%); angiotensin II, 16.0% (2.2%)] and adventitia [control, 26.4% (2.2%); angiotensin II, 26.6% (2.4%)]. In the arteries, bromodeoxyuridine indices were higher in the angiotensin II-infused rats [18.4% (2.3%)] than in the control animals [9.4% (2.8%)], but no difference was found in the veins [12% (2.9%) and 11.4% (2.6%) respectively]. Morphometry of the airway wall and mesenteric vasculature was no different in the two groups. Therefore a 2-week infusion of angiotensin II increases blood pressure and DNA synthesis in the mesenteric arteries, but does not cause airway remodelling, in the rat.
authors.affiliation: Department of Respiratory Medicine, West Glasgow Hospitals University NHS Trust, Glasgow, Scotland, U.K. SGRamsay@aol.com
authors.forename: S G
authors.initials: SG
authors.lastname: Ramsay
authors.forename: C J
authors.initials: CJ
authors.lastname: Kenyon
authors.forename: N
authors.initials: N
authors.lastname: Whyte
authors.forename: I C
authors.initials: IC
authors.lastname: McKay
authors.forename: N C
authors.initials: NC
authors.lastname: Thomson
authors.forename: G B
authors.initials: GB
authors.lastname: Lindop
mesh_terms: D000804:Angiotensin II / Q000097:blood / Q000494:pharmacology*; D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001973:Bromodeoxyuridine / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D017403:In Situ Hybridization; D008168:Lung / Q000033:anatomy & histology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012083:Renin / Q000032:analysis / Q000097:blood; D018709:Statistics, Nonparametric; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D000963:Antimetabolites; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D004247:DNA; D012083:Renin; D001973:Bromodeoxyuridine