Abstract:

Objective   To investigate the effects of rosiglitazone on expression of low-density lipoprotein receptor-related protein 1 (LRP-1) and the clearance mechanism of 40-aminoacid form of amyloid beta (Aβ1-40) in brain micro/small vessels in different courses of diabetic rats. Methods   Goto-Kakizaki (GK) rats were used as type 2 diabetic models. The GK rats were randomly divided into three groups: the 3-month-old GK rats group (DM3 group), the 6-month-old GK rats group (DM6 group) and the DM6 treated with rosiglitazone group (DM6RSG group). The DM3 group also acted as the control group. Expressions of Aβ1-40 and LRP-1 were detected by immunohistochemistry and enzyme-linked immunosorbent assays (ELISA). Expressions of LRP-1mRNA were detected by RT-PCR. Results    Compared to that of the DM3 group, expression of Aβ1-40 in the brain tissue was higher in the DM6 group (P<0.01). Compared to those of the DM6 group, expressions of LRP-1 and LRP-1mRNA in the brain tissue were higher in the DM6RSG group (P<0.05), however, expression of Aβ1-40 in the brain tissue was lower in the DM6RSG group than that of the DM6 group (P<0.01). Conclusion   With diabetes mellitus progression, the deposition of Aβ1-40 in brain micro/small vessels significantly increases. Rosiglitazone can up-regulate expressions of LRP-1 and LRP-1mRNA and then decrease the deposition of Aβ1-40 in diabetic brain tissue micro/small vessels.

Key words: Diabetes mellitus； Rats； Amyloid beta-protein； LDL-receptor related protein 1; Peroxisome proliferatoractivated receptor-γ