Characteristics of diabetic retinopathy in SDT rats.
BACKGROUND
We previously reported a new diabetic strain of the Sprague-Dawley rat, named the Spontaneously Diabetic Torii (SDT) rat. The purpose of the present study was to report the histologic and ultrastructural characteristics of diabetic retinopathy (DR) in a new animal model, the SDT rat.


METHODS
Fifty-three eyes of 43 SDT rats of various ages (35-82 weeks) were examined, of which 33 underwent histopathologic examination, 15 eyes fluorescein-dextran microscopy, and five eyes the trypsin digestion method.


RESULTS
Of the 33 eyes examined histopathologically, DR was identified in 20 eyes (61%). Large retinal folds mimicking diabetic tractional retinal detachment were observed in 20 eyes (61%). Retinal hemorrhages were seen in four eyes (12%). A neovascular fibrous membrane around the iris developed in five eyes (15%), of which two eyes had a massive anterior chamber hemorrhage. Of the 15 eyes examined by fluorescein-dextran microscopy, an area of nonperfusion and/or extensive hyperfluorescence was observed in 12 eyes (80%). Of the five eyes examined using the trypsin digestion method, acellular capillaries and pericyte loss were observed in four eyes (80%). Of the 53 eyes, the previously mentioned retinal changes of DR were observed in 36 eyes (68%). The rats with DR (49-82 weeks; mean, 60 weeks) were older than the rats without DR (35-55 weeks; mean, 40 weeks) (p < 0.001).


CONCLUSIONS
Large retinal folds mimicking tractional retinal detachment with extensive leakage of fluorescein around the optic disk was the most prominent finding of DR in SDT rats.
The Department of Ophthalmology, Omiya Medical Center, Jichi Medical University, Saitama 330-8503, Japan. kakeaki@omiya.jichi.ac.jp
Akihiro
A
Kakehashi
Yuka
Y
Saito
Kana
K
Mori
Norito
N
Sugi
Ryuichiro
R
Ono
Hiroko
H
Yamagami
Masami
M
Shinohara
Hiroyuki
H
Tamemoto
San-e
SE
Ishikawa
Masanobu
M
Kawakami
Yasunori
Y
Kanazawa
D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000473:pathology* / Q000503:physiopathology; D004195:Disease Models, Animal; D005123:Eye / Q000098:blood supply / Q000473:pathology; D005260:Female; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000473:pathology