Decrease of the Immunohistochemical Expression of Calcium Binding Protein (Calretinin) in the Retina of Hypercholesterolemic Rabbits Treated With Roziglitazone

Abstract

Purpose: : To evaluate early retinal abnormalities induced by a hypercholesterolemic diet and the prevention of these abnormalities after oral administration of rosiglitazone in rabbits.

Methods: : 54 New Zealand rabbits were divided into four groups: control group, normal diet; G1, hypercholesterolemic diet; G2, hypercholesterolemic diet plus a daily administration of 3 mg rosiglitazone from day 14 on; and G3, hypercholesterolemic diet plus a daily administration of 3 mg rosiglitazone since the start of the experiment. The sclera and choroid underwent histological and histomorphometric analyses and immunohistochemical analysis with Hamm 11 antibody. The retina underwent immunohistochemical analysis with anti-calretinin (intracellular calcium sensor) and GFAP antibodies.

Results: : No abnormalities were observed in the control group. G1 had significant increases in scleral and choroidal thicknesses compared with the control group (P=0.008) and group 3 (P<0.05). G1 scleral tissue presented significant immunoreactivity to Hamm 11 marker in relation to the other groups. G1 retina presented significant increases in immunoreactivity (P<0.001) to the anti-calretinin antibody compared with the other groups. G2 and G3 retina had significant (P<0.002) increases in calretinin immunoreactivity compared to control group. GFAP was negative in all groups.

Conclusions: : In this experimental model, hypercholesterolemic diet induced early abnormalities in the retina, choroid and sclera. Rosiglitazone preserved the anatomy of these structures.

Keywords: calcium • retina • drug toxicity/drug effects