The Olmesartan Effect in the Choroid-scleral Leukocyte Recruitment in Hypercholesterolemia Model

Abstract

Purpose: : Demonstrate that the blockade of angiotensin II AT-1 receptors, through the systemic administration of olmesartan, can reduce the MCP-1 expression and the resulting macrophage accumulation in the choroid and sclera of hypercholesterolemic rabbits.

Methods: : 32 New Zealand rabbits were divided into 3 groups: group 1(NG), was fed a standard rabbit diet; group 2 (HG) was fed a hypercholesterolemic diet; and group 3 (OG) was fed a hypercholesterolemic diet enriched with olmesartan. The rabbits underwent serum dosages of total cholesterol, triglyceride, HDL cholesterol and fasting blood glucose at the beginning of the experiment and at the euthanasia day. Sclera and choroid underwent immunohistochemical analysis with MCP-1 and RAM-11 markers.

Results: : No abnormality was detected in NG. HG showed a significant increase in immunoreactivity for MCP-1 in relation to NG (p= 0.001) and OG (p=0.004). HG showed a significant increase in immunoreactivity for RAM-11 of the choroid-scleral complex in relation to (p<0.001). A significant decrease in immunoreactivity for RAM-11 was observed in OG in relation to HG (p= 0.034) and a significant increase in immunoreactivity for RAM-11 was observed in OG in relation to NG (p=0.008).

Conclusions: : Olmesartan reduced the MCP-1 expression and the resultant macrophage accumulation in the choroid-scleral complex of hypercholesterolemic rabbits.

Keywords: receptors: pharmacology/physiology • inflammation • age-related macular degeneration