Abstract
Purpose: :
To evaluate, in a rabbit model, the degenerative histological abnormalities in the choroids and sclera following the daily administration of high cholesterol dosages as well as the possible prevention of degenerative abnormalities following systemic administration of oral rosiglitazone, an activator of agonist PPAR ocular gamma receptors.
Methods: :
55 New Zealand rabbits were studied and divided into four groups: Control Group (CG) (06 rabbits): normal diet for 6 weeks; Second group (G1) (13 rabbits): 1% cholesterol diet for 2 weeks and then a 0.5%cholesterol diet for 4 weeks. Third group (G2) (18 rabbits):1% cholesterol diet for 2 weeks and then a 0.5% cholesterol diet for 4 weeks; this group also received 3 mg of rosiglitazone daily after the third week from the beginning of the experiment. Fourth group (G3) (18 rabbits):1%cholesterol diet for 2 weeks and then a 0.5% cholesterol diet for 4 weeks; this group also received 3 mg rosiglitazone since the beginning of the experiments. Data was analyzed by Shapiro-Wilks-Test and P values lower than 0.05 were considered statistically significant.
Results: :
No abnormalities were observed in CG. However, G1 group showed a significant increase in sclerochoroidal thickness (301,48 micrometers-mc±50,12) compared with CG (239,09mc±24,33)(p=0,005).The G2 group showed a lower sclerochoroidal thickness (282,08mc±36,44) than G1 (301,48mc±50,12); however, this value was not statistically significant (p=0,222). G3 group showed a lower sclerochoroidal thickness (266,11mc±47,94 ) than G1 (301,48mc±50,12); this value was statistically significant (p=0,02). A higher number of histiocytes was observed in the scleral wall of G1 group.
Conclusions: :
This study revealed that hypercholesterolemia may lead to early degenerative abnormalities of the choroids and sclera of rabbits and that the activation of agonist PPAR ocular gamma receptors, by means of oral administration of rosiglitazone, proved to be effective for the preservation of choroids and sclera anatomy. These findings may have clinical relevance as the rosiglitazones may offer a new treatment modality for dry and/or exsudative AMD in human eyes.
Keywords: age-related macular degeneration