Abstract
Abstract: :
Purpose:The purpose of this study was to investigate the effects of HAM upon clinical and biochemical features of rabbit corneas submitted to limbal injury Methods: Right corneas of 20 rabbits underwent total peritomy and keratolimbectomy, followed by application of 0.5 M NaOH. Cryo–preserved HAM were sutured on the ocular surface of those eyes in ten animals (G1), and the right eyes of the remaining ten animals (G2) were kept uncovered. Normal contralateral eyes were used as matched controls at all groups. All animals were clinically evaluated everyday. At the 30th day, the rabbits were killed and both corneas were removed and sent for histopathological and biochemical analysis. Results:All animals presented with intense blepharospasm/photophobia, mucous secretion, and corneal neovascularization, but at the end of the experiment, the HAM–treated corneas presented less epithelial defects and cornea opacities were less severe than the untreated injured ones. Low molecular weight proteoglycans (PGs) of the lumican/decorin family were isolated from both control and experimental corneas and its concentration was reduced to a half in untreated injured corneas, and to 1/3 in the HAM–treated ones. Keratan sulfate (KS) and dermatan sulfate (DS) were identified as the main corneal glycosaminoglycans. The relative amounts of KS were very low in all injured corneas. The protein concentration was greatly increased in untreated injured corneas, but its concentration was equal to normal in the HAM–treated ones. Conclusions:Cryo–preserved HAM may be an effective alternative in ocular surface reconstructive surgery since the HAM–treated corneas demonstrated better clinical outcome and less epithelial defects. It seems that HAM had an inhibitory effect upon protein and PG biosynthesis. The HAM inhibitory effect upon PG and protein biosynthesis could allow the proper collagen organization, preventing corneal opacity. (CNPq, FAPESP, CAPES, SPDM)
Keywords: glycoconjugates/glycoproteins • cornea: basic science