Inhibition Of TGF-β1and α-SMA Expression By Bevacizumab For Preventing Haze After Off-flap Epi-LASIK

Purpose:To investigate the effect of subconjunctival injections of Bevacizumab, an anti VEGF antibody, on the inhibition of cornael Transforming grown facter-β1(TGF-β1) andα-smooth muscle actin(α-SMA) expression for preventing Haze in corneal wound healing after Off-flap epipolis laser in situkeratomileusis (Off-flap Epi-LASIK).Method:There were twenty-six adult Qingzilan health rabbits weighted2.5-3. Okg, which were divided randomly into four groups. Control group had two rabbits (four eyes), then twenty-four rabbits (fouth-eight eyes) performed on Off-flap Epi-LASIK, which averagely assigned into the other three groups:Group1was Treatment Group which received a subconjunctival injection of Bevacizumab2.5mg (0. lml)5min after surgery; Group2was Intensive Treatment Group which received subconjunctival injection of Bevacizumab2.5mg (0.1ml)5min and4days after surgery; Group3was Untreatment Group, the saline-treated control.Clinical examination under slitlamp was performed to evaluate corneal opacity and taked notes the day in which epithelial tissue were recovere and the grade of Haze in1w and4w. Eyeball was enucleated in1w and4w post-surgery, and corneal repair was assessed through hemotoxylin and eosin(HE) stain and periodic acid-Schiff (PAS) stain. The expression of TGF-β1、α-SMA in the corneal cells was examined by immunohistochemistry. Computer assisted quantitative image analysis was used to measure Positive Unite value expressed by TGF-β1、α-SMA in the center corneal area.Result:1、After off-flap Epi-LASIK, epithelial tissue of three group were recovered in4or5days, All of these difference were not statistically significant (P>0.05);2, Untreatment Group reach an average of grade1.25by lweek after operation, higher than Treatment Group and Intensive Treatment Group,these difference were statistically significant (P<0.01); but the difference of Treatment Group and Intensive Treatment Group was not statistically significant (P>0.05); The same result in4week;3,1week after off-flap Epi-LASIK, Untreatment Group’ s the center of corneal epithelium cells were proliferated. The numbers of fibroblasts were clearly increased and the collagen fibrils were irregularly arranged in corneal stroma, Inflammatory cells appeared; Treatment Group and Intensive Treatment Group’s the center of corneal epithelium cells and collagen fibrils were more regularly arranged.4week after surgery, Treatment Group and Intensive Treatment Group’ s morphological features were very similar to normal cornea’s. Untreatment Group’s the center of corneal epithelium cells were proliferated and squamous epithelization, the size of basement cells were column structure but irregulate; The numbers of f ibroblasts also were clearly increased and the collagen fibrils were irregularly arranged.4,1and4week after Off-flap Epi-LASIK, TGF-β1and α-SMA expression were increased in the stroma of Untreatment Group, but decreased in Treatment Group and Intensive Treatment Group, these difference were statistically significant (P<0.01).5, Untreatment Group of basement membrane as revealed by PAS stain, was thinner and discontinuous in many regions of operative cornea,whether1week or4week after surgery. In Treatment Group and Intensive Treatment Group, basement membrane was mainly reestablished by Bevacizumab lweek post-operative. And in4week, the integrity of basement membrane was like normal. Conclusion:1、Off-flap Epi-LASIK make the numbers of f ibroblasts increased and the collagen fibrils irregularly arranged in corneal stroma to Haze in early healing time.2、Bevacizumab has no influence on the reepithelialization.3、Bevacizumab can decrease the expression of TGF-β1and α-SMA for preventing Haze in rabbits’cornea after Off-flap Epi-LASIK.4、Bevacizumab play an important role in regenerating the basement membrane in the cornea after operative, and minimizing fibrotic repair by creating a physical barrier to improve corneal opacity.5、discuss the mechanism of Inhibition of TGF-β1and α-SMA expression by Bevacizumab for preventing haze after off-flap Epi-LASIK in rabbits’cornea Accordding to safety and efficiency of Bevacizumab, it seems to be clinically needed in the management of Haze of corneal surface refractive surgery.