Abstract
Purpose: :
Trabeculectomy creates a filtration channel that diverts eye fluid to create a "bleb" resulting in a lower IOP and preserving vision. Over time, wound healing can lead to filtration failure due to fibrosis. Amniotic membrane (AM) shows impressive anti–inflammatory, anti–scarring, and anti–angiogenic properties in the treatment of ocular burns, some corneal ulcers, and limbal stem cell deficiency. Since these properties are desirable for trabeculectomy outcomes, our objective is to study the anti–inflammatory and anti–fibrotic effects of AM.
Methods: :
We established assays to measure fibroblast proliferation and superoxide dismutase (SOD) activity in neutrophils. Using the 3–(4,5–dimethythiazolyl–2)–2, 5–diphenyltetrazolium bromide (MTT) cell proliferation assay, fibroblast proliferation was quantified by spectrophotometry by the reduction of tetrazolium salt in metabolically active cells. The assay is conducted in a 96 well format by plating 5000 cells/well and comparing control, mitomycin (0.2 mg/ml) treatment, and AM exposure. Using the Cayman Chemical (Ann Arbor, MI) SOD assay kit, to measures the reduced tetrazolium salt dye as an index of superoxide radicals generated by xanthine oxidase and hypoxanthine. Superoxide dismutase (SOD) catalyzes the dismutation of the superoxide anion into hydrogen peroxide and molecular oxygen. The neutrophils were isolated by step–density centrifugation. Endogenous cytosolic SOD activity and the effects of AM were quantified using the SOD Assay Kit.
Results: :
Cryo–preserved amniotic membrane appears to have anti–proliferation effects in fibroblast and anti–inflammatory effects in neutrophil SOD. AM caused a decrease in human fibroblast growth significantly (p<0.05, n=5, +/– standard deviation, Kruskal–Wallis test) and a decrease in endogenous cytosolic SOD from human neutrophils (p<0.05, paired Student t–test)
Conclusions: :
Our preliminary findings support that cryo–perserved AM decreases fibrotic proliferation and decreases endogenous neutrophil SOD activity. These effects may be beneficial to improve clinical trabeculectomy outcome. Acknowledgement: Soojie Yu performed the fibroblast proliferation assays.
Keywords: inflammation • proliferation • wound healing