Lens epithelial cell apoptosis initiates diabetic cataractogenesis in the Zucker diabetic fatty rat.
BACKGROUND
It has been suggested that damage of lens epithelial cell (LEC) may play an important role in cataract formation. Nitric oxide is involved in cataract development. Here, we investigated the relationship between LEC damage and iNOS expression in the Zucker diabetic fatty (ZDF) rat.


METHODS
At 21 weeks of age, the eyes were enucleated and the lens opacity was then examined. Apoptosis were detected by TUNEL assay, and the expression of iNOS and NF-kappaB activation were studied by immunohistochemistry and southwestern histochemistry respectively.


RESULTS
In 21-week-old male ZDF rats, cataract was developed, TUNEL-positive LECs were markedly increased, and the expression levels of iNOS mRNA and protein were significantly upregulated. The expression pattern of iNOS was closely correlated with apoptotic change of LECs. In addition, advanced glycation end products (AGEs) were accumulated in cytoplasm of LECs. Activated NF-kappaB was mainly detected in nucleus of LECs.


CONCLUSIONS
The higher expressions of AGEs, NF-kappaB and iNOS in LECs of diabetic rats suggest that these factors are involved in apoptosis of LEC alterations related to diabetic cataract.
Kim
Junghyun
J
Diabetic Complications Research Center, Division of Traditional Korean Medicine (TKM) Integrated Research, Korea Institute of Oriental Medicine, 483 Exporo, Yuseong-gu, Daejeon, 305-811, South Korea. jskim@kiom.re.kr
Kim
Chan-Sik
CS
Sohn
Eunjin
E
Kim
Hyojun
H
Jeong
Il-Ha
IH
Kim
Jin Sook
JS
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002386:Cataract / Q000209:etiology* / Q000378:metabolism; D048909:Diabetes Complications; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology*; D017127:Glycation End Products, Advanced / Q000378:metabolism; D006651:Histocytochemistry; D017403:In Situ Hybridization; D020287:In Situ Nick-End Labeling; D007908:Lens, Crystalline / Q000378:metabolism / Q000473:pathology*; D008297:Male; D016328:NF-kappa B / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011924:Rats, Zucker; D015854:Up-Regulation
D017127:Glycation End Products, Advanced; D016328:NF-kappa B; D012333:RNA, Messenger; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat