Evaluation of choroid and sclera early alterations in hypercholesterolemic rabbits: histologic and histomorphometric study

• Published in: Arquivos brasileiros de oftalmologia Vol. 72; no. 1; pp. 68 - 74
• Main Authors: Torres, Rogil José de Almeida, Maia, Maurício, Noronha, Lucia, Farah, Michel Eid, Luchini, Andréa, Brik, Décio, Muccioli, Cristina, Précoma, Dalton Bertolin
• Format: Journal Article
• Language: Portuguese
• Published: Brazil 01-01-2009
• Subjects: Animals; Cholesterol, Dietary - adverse effects; Choroid - metabolism; Choroid - pathology; Disease Models, Animal; Hypercholesterolemia - etiology; Hypercholesterolemia - metabolism; Male; Rabbits; Sclera - metabolism; Sclera - pathology; Statistics, Nonparametric
• ISSN: 1678-2925

To demonstrate experimentally, by means of histological and histomorphometric examinations, the sclera and choroid degenerative alterations, which take place at an early stage due to a hypercholesterolemic diet.
New Zealand rabbits were divided into two groups: CG (control group) of 6 rabbits (6 eyes) received a regular diet for 6 weeks; G1, of 12 rabbits (12 eyes), was first fed a 1% cholesterol diet (Sigma-Aldrich) for 2 weeks and then from the 14th day on a 0.5% cholesterol diet (Sigma-Aldrich). The eyes underwent a histological analysis, stained with hematoxiline-eosine, and a morphometric examination. The histomorphometric analysis was performed in the posterior region, adjacent to the optic disk, and in the peripheral region.
The CG presented a mean sclera and choroid thickness of 228.61 +/- 31.71 micrometers in the peripheral region, while the thickness in the posterior region was approximately 246.07 +/- 25.66 micrometers. In G1, these values were 303.56 +/- 44.21 micrometers in the peripheral region and 295.59 +/- 62.59 in the posterior region. There was a statistically significant difference in the sclera and choroid thickness between the groups in the peripheral region (p<0.001); however, this difference did not occur in the posterior region (p=0.250). The large number of histiocytes and collagen fibers accounted for the increase of G1 wall thickness in relation to CG.
This study demonstrated that the hypercholesterolemic diet in rabbits induces a fast increase in the choroid and sclera thickness, mainly due to the increase in the number of histiocytes and collagen fibers.