AQUEOUS TRANSFORMING GROWTH FACTOR-BETA-I LEVELS IN RABBIT EYES AFTEREXCIMER-LASER PHOTOABLATION

Transforming growth factor beta (TGF-beta) plays an important role in anterior segment wound healing, by controlling the cell proliferation and differentiation, angiogenesis, extracellular matrix composition an d mediating the immunosuppressive properties of the aqueous humor. The present study was undertaken to clarify the possible changes of aqueo us humor TGF-beta(1) levels after excimer laser photoablation. Twenty- eight New Zealand rabbits were divided into four groups of 7 rabbits e ach. Group 1 served as control, the central 7 mm of corneal epithelium was removed in groups 2, 3 and 4. We performed 50-mu m corneal photoa blation in group 3, and 100-mu m ablation in group 4. After 48 h we me asured the TGF-beta(1) levels of the aqueous humor by ELISA method. Th e mean TGF-beta(1) value of the aqueous humor was found to be 162.94 /- 13.73 pg/ml in the control group. Mechanical deepithelialization di d not change the TGF-beta(1) levels of the aqueous humor (p>0.05). The re was no significant difference between the 50-mu m photoablated grou p and the controls (p>0.05), but the TGF-beta(1) levels of the 100-mu m photoablated group were found to be significantly higher than those of both the control group and 50-mu m photoablated group (p<0.05). Man y factors and cytokines may induce corneal haze and myopic regression after excimer laser photoablation; our study demonstrated that TGF-bet a(1) is one of these factors and there is a positive correlation betwe en the depth of corneal photoablation and aqueous TGF-beta(1), concent rations.