Effect of poly（DL-lactide-co-glycolide） on scar formation after glaucoma filtration surgery

Background Glaucoma filtering surgery （GFS） is the most common procedure performed in the treatment of glaucoma.Although antiscarring agents help prevent postsurgical scarring and improve glaucoma surgical outcomes,they may be associated with an increased incidence of severe and potentially blinding complications.Poly（DL-lactide-co-glycolide） （PDLLA/GA） is a bioresorbable polymer,which can be prepared with a large range of physical,mechanical,and biological properties and has been widely used in medicine,including as an absorbable suture and a drug carrier and especially as a scaffold in tissue engineering.This study aimed to evaluate the effect of PDLLA/GA on scar formation after glaucoma filtration surgery （GFS）.Methods Forty-eight New Zealand white rabbits were divided into two groups randomly and GFS was performed on the right eye of each.PDLLA/GA membranes were put under the sclera flap for evaluation.GFS with no membrane inserted served as control.Clinical evaluations of intraocular pressure （lOP） and the presence of a filtration bleb were performed at intervals （3 days,1,2,4,8,12,20,and 24 weeks） postoperatively.At each time point,three eyes per group were excised to observe histological changes such as inflammation and scar formation and the expression of collagen type Ⅳ,proliferating cell nuclear antigen （PCNA）,matrix metalloproteinase-9 （MMP-9）,and tissue inhibitor of metalloproteinase-1 （TIMP-1）.The expression of connective tissue growth factor （CTGF） mRNA was determined by reverse transcription-polymerase chain reaction.Results The lower lOP level and an effective bleb were maintained for a long time after GFS in the PDLLA/GA group.The histological analysis showed less inflammation and scar formation,weaker expression of collagen type Ⅳ and PCNA,more intense MMP-9 and TIMP-1,slightly elevated ratio of MMP-9 and TIMP-1,and a smaller increase in CTGF mRNA postoperatively in the PDLLA/GA group but less than the control group （P ＜0.05）.Conclusion PDLLA/GA membranes may be promising for preventing fibrosis after GFS.