This Article Free Full Text Free Free Full Text (Free PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Imaoka, M. Articles by Furuhama, K. Search for Related Content PubMed PubMed Citation Articles by Imaoka, M. Articles by Furuhama, K. Social Bookmarking                   What's this?

Age- and Sex-Related Differences in Spontaneous Hemorrhage and Fibrosis of the Pancreatic Islets in Sprague–Dawley Rats

Drug Safety Research Laboratory, Daiichi Pharmaceutical Co., Ltd., Tokyo 134-8630, Japan

Correspondence: Address correspondence to: Masako Imaoka, Drug Safety Research Laboratory, Daiichi Pharmaceutical Co., Ltd., 1-16-13, Kita-Kasai, Edogawaku, Tokyo 134-8630, Japan; e-mail:Imaokqd1{at}daiichipharm.co.jp

To elucidate the spontaneous occurrence of hemorrhage in the pancreatic islet, naïve Crj:CD(SD)IGS rats were given a commercially available standard diet ad libitum over 20 weeks, and were sequentially examined. Islet hemorrhage was morphologically observed from 12 weeks of age, and its incidence was significantly higher in males than in females, with a wide distribution in all pancreatic lobes. The incidence (%) of affected islets to examined islets was increased with age. Hemorrhage was accompanied by brownish pigmentation, and reacted positively for iron by Prussian/Berlin blue staining. In 26 weeks old, most of the islets were dissected by dense fibrous tissue into small nests, and disarranged β cells were detected by insulin immunostaining. Ultrastructurally, no apparent morphological change was seen in any islet endothelial cell, although blood leakage with migrated macrophages and dense collagen fibers was observed around the capillaries. In serum biochemistry of rats aged 26 weeks, the estradiol level in males with hemorrhage was significantly lower than that in males with non-hemorrhage, presumably suggesting the lack of capillary protective ability. Next, when rats were given a high fat/protein diet over 20 weeks to clarify whether it accelerated the frequency or timing of hemorrhage, its occurrence was essentially identical to that of the animals fed the standard diet. In conclusion, the onset of spontaneous islet hemorrhage was observed predominantly in aged males, resulting from the low estradiol level in serum.

Key Words: Islet of Langerhans • Sprague-Dawley rats • hemorrhage • fibrous segmentations • spontaneous lesions

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?