Metalloproteinase inhibition ameliorates hypertension and prevents vascular dysfunction and remodeling in renovascular hypertensive rats.
Altered activity of matrix metalloproteinases (MMPs) is implicated in the vascular remodeling of hypertension. We examined whether increased MMP-2 expression/activity plays a role in the vascular remodeling and dysfunction found in the two-kidney, one-clip (2K-1C) hypertension. Sham operated or 2K-1C hypertension rats were treated with doxycycline 30mg/(kgday) (or vehicle). Systolic blood pressure was monitored weekly. After 8 weeks of treatment, aortic rings were isolated to assess endothelium-dependent and independent relaxations. Quantitative morphometry of structural changes, collagen, and elastin contents in the aortic wall were studied in hematoxylin/eosin, Sirius Red, and Orceine stained aortic sections, respectively. Aortic MMP-2 levels were determined by gelatin zymography and aortic MMP-2 proteolytic activity was measured using DQ gelatin as the substrate after MMP-2 was captured by a specific antibody and immobilized on a microplate. Aortic MMP-2/tissue inhibitor of metalloproteinases (TIMP)-2 mRNA levels were determined by real time RT-PCR. Doxycycline attenuated 2K-1C hypertension (215+/-8mmHg versus 167+/-13mmHg in 2K-1C rats and 2K-1C+doxy rats, respectively; P<0.01) and prevented the 35% reduction in endothelium-dependent vasorelaxation found in 2K-1C rats. Doxycycline prevented the increases in media thickness, and was associated with lower media/lumen and cross-sectional areas (all P<0.01). Doxycycline also prevented excessive collagen and elastin deposition in the vascular wall. Increased MMP-2 and Pro-MMP-2 levels and MMP-2 activity were found in the aortas of 2K-1C rats (all P<0.05). A 21-fold increase (P<0.001) in the ratio of MMP-2/TIMP-2 mRNA expression was found in the 2K-1C group, whereas this ratio remained unaltered in 2K-1C+doxy rats. Our results suggest that MMP-2 plays a role in 2K-1C hypertension and its structural and functional vascular changes, which were attenuated by doxycycline.
Department of Pharmacology, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirao Preto, SP, Brazil.
Michele M
MM
Castro
Elen
E
Rizzi
Lívia
L
Figueiredo-Lopes
Karla
K
Fernandes
Lusiane M
LM
Bendhack
Dimitrius Leonardo
DL
Pitol
Raquel F
RF
Gerlach
Jose E
JE
Tanus-Santos
D000818:Animals; D001013:Aorta, Thoracic / Q000201:enzymology / Q000503:physiopathology*; D004318:Doxycycline / Q000494:pharmacology*; D004792:Enzyme Precursors / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D018093:Gelatinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D006977:Hypertension, Renal / Q000201:enzymology / Q000503:physiopathology*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism; D014664:Vasodilation
D004792:Enzyme Precursors; D061965:Matrix Metalloproteinase Inhibitors; D011480:Protease Inhibitors; D012333:RNA, Messenger; D019716:Tissue Inhibitor of Metalloproteinase-2; D018093:Gelatinases; D008666:Metalloendopeptidases; C069860:progelatinase; D020778:Matrix Metalloproteinase 2; D004318:Doxycycline