Acute and chronic hypoxia as well as 7-day recovery from chronic hypoxia affects the distribution of pulmonary mast cells and their MMP-13 expression in rats.
Chronic hypoxia results in pulmonary hypertension due to vasoconstriction and structural remodelling of peripheral lung blood vessels. We hypothesize that vascular remodelling is initiated in the walls of prealveolar pulmonary arteries by collagenolytic metalloproteinases (MMP) released from activated mast cells. Distribution of mast cells and their expression of interstitial collagenase, MMP-13, in lung conduit, small muscular, and prealveolar arteries was determined quantitatively in rats exposed for 4 and 20 days to hypoxia as well as after 7-day recovery from 20-day hypoxia (10% O2). Mast cells were identified using Toluidine Blue staining, and MMP-13 expression was detected using monoclonal antibody. After 4, but not after 20 days of hypoxia, a significant increase in the number of mast cells and their MMP-13 expression was found within walls of prealveolar arteries. In rats exposed for 20 days, MMP-13 positive mast cells accumulated within the walls of conduit arteries and subpleurally. In recovered rats, MMP-13 positive mast cells gathered at the prealveolar arterial level as well as in the walls of small muscular arteries; these mast cells stayed also in the conduit part of the pulmonary vasculature. These data support the hypothesis that perivascular pulmonary mast cells contribute to the vascular remodelling in hypoxic pulmonary hypertension in rats by releasing interstitial collagenase.
Vajner
Ludek
L
Department of Histology and Embryology, Charles University, Prague. ludek.vajner@lfmotol.cuni.cz
Vytásek
Richard
R
Lachmanová
Vera
V
Uhlík
Jirí
J
Konrádová
Václava
V
Novotná
Jana
J
Hampl
Václav
V
Herget
Jan
J
D000208:Acute Disease; D000818:Animals; D002908:Chronic Disease; D017364:Collagenases / Q000378:metabolism*; D006976:Hypertension, Pulmonary / Q000201:enzymology / Q000209:etiology / Q000473:pathology; D000860:Hypoxia / Q000150:complications / Q000201:enzymology / Q000473:pathology*; D008168:Lung / Q000201:enzymology / Q000473:pathology*; D008297:Male; D008407:Mast Cells / Q000201:enzymology / Q000473:pathology*; D053509:Matrix Metalloproteinase 13; D051381:Rats; D017208:Rats, Wistar
D017364:Collagenases; D053509:Matrix Metalloproteinase 13; C507083:Mmp13 protein, rat