Photochemically induced colonic ischaemic lesions: a new model of ischaemic colitis in rats.
BACKGROUND
Recent clinical studies suggest that ischaemic colitis is caused by a microcirculatory disturbance that involves thrombosis of the colon.


OBJECTIVE
To establish a new model of photochemically induced ischaemic colitis in rats.


METHODS
Thirty male Wistar rats were anaesthetised with amobarbital, the femoral veins were cannulated and laparotomies were performed. The serosal surface of the proximal colon was irradiated by using a krypton laser (wavelength 568 nm, 20 mW) for four minutes. An intravenous infusion of a photosensitising dye, rose bengal (20 mg/kg body weight), was administered over 90 seconds, beginning at the start of irradiation. Rats were killed immediately (n = 4), 12 hours (n = 2), 24 hours (n = 10), three days (n = 4), seven days (n = 4), 14 days (n = 2), or 28 days (n = 2) after irradiation. Two control rats received laser irradiation without dye infusion. Specimens of the irradiated sites were examined by using histopathology.


RESULTS
Localised ulcers of the colon were present in rats killed at 12 hours, 24 hours, three days, and seven days after irradiation. Microscopy findings were consistent with the features of human ischaemic colitis. Reproducible ulcerative lesions were produced by photothrombosis of microvessels in the colon.


CONCLUSIONS
This model may be useful for further investigation of the pathophysiology of ischaemic colitis.
Yano
Y
Y
Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Yao
H
H
Aoyagi
K
K
Kawakubo
K
K
Nakamura
S
S
Doi
K
K
Ibayashi
S
S
Fujishima
M
M
D000818:Animals; D017091:Colitis, Ischemic / Q000209:etiology / Q000473:pathology; D003108:Colonic Diseases / Q000209:etiology / Q000473:pathology; D004195:Disease Models, Animal; D005456:Fluorescent Dyes; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D007834:Lasers; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012395:Rose Bengal; D013927:Thrombosis / Q000209:etiology / Q000473:pathology; D014456:Ulcer / Q000209:etiology / Q000473:pathology
D005456:Fluorescent Dyes; D012395:Rose Bengal