[Evaluation of choroid and sclera early alterations in hypercholesterolemic rabbits: histologic and histomorphometric study].
OBJECTIVE
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.


CONCLUSIONS
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.
Departamento de Oftalmologia da Universidade Federal de São Paulo (SP) - Brasil. rjat@terra.com.br
Rogil José de Almeida
RJ
Torres
Maurício
M
Maia
Lucia
L
Noronha
Michel Eid
ME
Farah
Andréa
A
Luchini
Décio
D
Brik
Cristina
C
Muccioli
Dalton Bertolin
DB
Précoma
D000818:Animals; D002791:Cholesterol, Dietary / Q000009:adverse effects*; D002829:Choroid / Q000378:metabolism / Q000473:pathology*; D004195:Disease Models, Animal; D006937:Hypercholesterolemia / Q000209:etiology / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D012590:Sclera / Q000378:metabolism / Q000473:pathology*; D018709:Statistics, Nonparametric
D002791:Cholesterol, Dietary