Inhibition Effect of Tetrandrine on Haze Formation after Epi-LASIK Surgery in Rabbits

Purpose: To observe the inhibitory effect of tetrandrine on haze formation after Epi-LASIK surgery in rabbits. Materials and Methods: Twenty-seven healthy New Zealand rabbits were selected and underwent Epi-LASIK surgery. According to a self comparison principle, these rabbits were randomly divided into three groups. The first group was treated with tetrandrine eye drops (Tet), the second (negative control, NC) group was treated with pure solvent, and the third group was treated with fluorometholone (FML) solvent. Haze grades of each group were respectively observed by slit lamp exam at half-month, one month, and two months after surgery. After corneal tissues were extracted, optical microscopy, Sirius Red staining, immunohistochemistry, and semi-quantitative RT-PCR tests were conducted, in order to test collagen formation of operated eyes after surgery and expression of transformation growth factor beta 2 (TGF-beta(2)) in corneal stroma. Results: At a half month and one month after surgery, haze grades and type. collagen expression in Tet and FML groups were significantly lower than that in NC groups (P < 0.01). No statistical difference was observed between Tet and FML groups. Immunohistochemistry showed that, at each time point after surgery, expressions of TGF-beta(2) protein in Tet and FML groups were significantly lower than that in the NC group (P < 0.01), whereas there was no statistical difference between Tet and FML groups. The expression level of TGF-beta(2) protein increased, reaching its peak one month after surgery. RT-PCR also showed that, at each point after surgery, the TGF-beta(2) mRNA expression in Tet and FML groups was lower than that in the NC group (P < 0.01), nevertheless no statistical difference was observed between Tet and FML groups. Conclusions: Like FML, Tet could inhibit haze formation in rabbits after Epi-LASIK surgery, possible through TGF-beta(2)-collagen-III pathway.