Vascular injury after whole thoracic x-ray irradiation in the rat.
OBJECTIVE
To study vascular injury after whole thoracic irradiation with single sublethal doses of X-rays in the rat and to develop markers that might predict the severity of injury.


METHODS
Rats that received 5- or 10-Gy thorax-only irradiation and age-matched controls were studied at 3 days, 2 weeks, and 1, 2, 5, and 12 months. Several pulmonary vascular parameters were evaluated, including hemodynamics, vessel density, total lung angiotensin-converting enzyme activity, and right ventricular hypertrophy.


RESULTS
By 1 month, the rats in the 10-Gy group had pulmonary vascular dropout, right ventricular hypertrophy, increased pulmonary vascular resistance, increased dry lung weights, and decreases in total lung angiotensin-converting enzyme activity, as well as pulmonary artery distensibility. In contrast, irradiation with 5 Gy resulted in only a modest increase in right ventricular weight and a reduction in lung angiotensin-converting enzyme activity.


CONCLUSIONS
In a previous investigation using the same model, we observed that recovery from radiation-induced attenuation of pulmonary vascular reactivity occurred. In the present study, we report that deterioration results in several vascular parameters for </=1 year after 10 Gy, suggesting sustained remodeling of the pulmonary vasculature. Our data support clinically relevant injuries that appear in a time- and dose-related manner after exposure to relatively low radiation doses.
Department of Medicine, Division of Pulmonary and Critical Care, Medical College of Wisconsin, Milwaukee, WI, USA.
S N
SN
Ghosh
Q
Q
Wu
M
M
Mäder
B L
BL
Fish
J E
JE
Moulder
E R
ER
Jacobs
M
M
Medhora
R C
RC
Molthen
D000818:Animals; D001835:Body Weight / Q000528:radiation effects; D005260:Female; D006400:Hematocrit; D017380:Hypertrophy, Right Ventricular / Q000209:etiology; D008168:Lung / Q000098:blood supply / Q000201:enzymology / Q000528:radiation effects*; D055370:Lung Injury; D011651:Pulmonary Artery / Q000528:radiation effects*; D011667:Pulmonary Veins / Q000528:radiation effects*; D011829:Radiation Dosage; D011833:Radiation Injuries, Experimental / Q000201:enzymology / Q000473:pathology*; D051381:Rats; D012083:Renin / Q000378:metabolism; D013909:Thorax / Q000528:radiation effects; D014655:Vascular Resistance / Q000528:radiation effects
D012083:Renin