Abstract:

Objective  To research low density lipoprotein receptor-related protein 1（Lrp-1）and Amyloid Beta 1-40 （Aβ1-40）content in the brain tissue of rats with diabetic mellitus， as well as the relationship between them. Methods  The type 2 diabetic rat model was induced by streptozotocin and highcarbonhydratefat diet. All Wistar rats were randomly assigned into four groups: normal rats aged 3 months and 6 months, and diabetic rats aged 3 months(DM3) and 6 months(DM6). Then expressions of Lrp1 and Aβ1-40 were detected by immunohistochemistry and enzyme-linked immunosorbent assays(Elisa) respectively.  Results  ① Aβ1-40 was detected in several parts of the brain tissue, such as the cytoplasm or cytomembrane of neurons or neuroglial cells of the cerebral cortex and hippocampus,  and adventitia or smooth muscle cells of the  pial artery or the perforating branch. More Aβ1-40 was detected in diabetic rats than in sameage normal ones（P＜0.05）. Expression of Aβ1-40 increased with age in both groups（P＜0.05）; ②Lrp-1 was also detected in several parts of the brain tissue, such as the cytoplasm or cytomembrane of neurons or neuroglial cells of cerebral cortex and hippocampus, intima of perforating arteries, and capillary endothelial cells. On the contrary, less Lrp-1 was detected in diabetic rats（P＜0.05）, and expression of Lrp1 decreased with age（P＜0.05）; ③ Aβ1-40 had a typical negative linear correlation with Lrp-1. Conclusion  Deposition of Aβ1-40 was related to down-regulation of Lrp-1.

Key words: Diabetes mellitus； Cerebrovascular； Lipoprotein receptor-related protein 1; Amyloid Beta 1-40;  Rats, wistar