PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.
Cholesterol; Choroid; Diet; Hypercholesterolemia; Macular degeneration; Atherosclerosis; Sclera; Models, animal; Rabbits; Comparative study
