title: Doxycycline, a matrix metalloprotease inhibitor, reduces vascular remodeling and damage after cerebral ischemia in stroke-prone spontaneously hypertensive rats.
abstract: Matrix metalloproteases (MMPs) are a family of zinc peptidases involved in extracellular matrix turnover. There is evidence that increased MMP activity is involved in remodeling of resistance vessels in chronic hypertension. Thus we hypothesized that inhibition of MMP activity with doxycycline (DOX) would attenuate vascular remodeling. Six-week-old male stroke-prone spontaneously hypertensive rats (SHRSP) were treated with DOX (50 mg·kg(-1)·day(-1) in the drinking water) for 6 wk. Untreated SHRSP were controls. Blood pressure was measured by telemetry during the last week. Middle cerebral artery (MCA) and mesenteric resistance artery (MRA) passive structures were assessed by pressure myography. MMP-2 expression in aortas was measured by Western blot. All results are means ± SE. DOX caused a small increase in mean arterial pressure (SHRSP, 154 ± 1; SHRSP + DOX, 159 ± 3 mmHg; P < 0.001). Active MMP-2 expression was reduced in aorta from SHRSP + DOX (0.21 ± 0.06 vs. 0.49 ± 0.13 arbitrary units; P < 0.05). In the MCA, at 80 mmHg, DOX treatment increased the lumen (273.2 ± 4.7 vs. 238.3 ± 6.3 μm; P < 0.05) and the outer diameter (321 ± 5.3 vs. 290 ± 7.6 μm; P < 0.05) and reduced the wall-to-lumen ratio (0.09 ± 0.002 vs. 0.11 ± 0.003; P < 0.05). Damage after transient cerebral ischemia (transient MCA occlusion) was reduced in SHRSP + DOX (20.7 ± 4 vs. 45.5 ± 5% of hemisphere infarcted; P < 0.05). In the MRA, at 90 mmHg DOX, reduced wall thickness (29 ± 1 vs. 22 ± 1 μm; P < 0.001) and wall-to-lumen ratio (0.08 ± 0.004 vs. 0.11 ± 0.008; P < 0.05) without changing lumen diameter. These results suggest that MMPs are involved in hypertensive vascular remodeling in both the peripheral and cerebral vasculature and that DOX reduced brain damage after cerebral ischemia.
authors.affiliation: Dept. of Pharmacology and Toxicology, B346 Life Sciences Bldg., Michigan State Univ., East Lansing, MI 48824, USA. pirespau@msu.edu
authors.forename: Paulo W
authors.initials: PW
authors.lastname: Pires
authors.forename: Curt T
authors.initials: CT
authors.lastname: Rogers
authors.forename: Jonathon L
authors.initials: JL
authors.lastname: McClain
authors.forename: Hannah S
authors.initials: HS
authors.lastname: Garver
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Fink
authors.forename: Anne M
authors.initials: AM
authors.lastname: Dorrance
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D002545:Brain Ischemia / Q000188:drug therapy* / Q000473:pathology*; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology; D004318:Doxycycline / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects; D007668:Kidney / Q000187:drug effects; D017078:Laser-Doppler Flowmetry; D008297:Male; D061965:Matrix Metalloproteinase Inhibitors; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology; D020768:Middle Cerebral Artery / Q000473:pathology*; D009929:Organ Size / Q000187:drug effects; D011480:Protease Inhibitors / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D020521:Stroke / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology*; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology
chemical_list: D061965:Matrix Metalloproteinase Inhibitors; D011480:Protease Inhibitors; D004318:Doxycycline