Abstract
Purpose: :
Pterygium is one of the most common ocular diseases in ophthalmology, and is a bening, fibrovascular lesion, originated from the bulbar conjunctiva. About the cause of pterigium, it has been proposed that ultraviolet radiation is important in the development of the pterygium. Some authors suggest that pterygium and cancer share features and this raise the possibility that pterygium is a neoplastic-like growth disorder. We reported that peroxiredoxin 2 (PRX2) was overexpressed in pterygium (ARVO 2010). PRX2 is associated with apoptosis protection in cardiomyocytes, regulating apoptotic proteins from intrinsic pathway. The aim of this work was to analyze the expression of apoptotic proteome in primary pterygium in comparison to healthy conjunctiva.
Methods: :
Four primary pterygia and healthy conjunctiva samples were analyzed by human apoptosis protein array. Tissues were lysed and 200µg of proteins obtained were incubated with the arrays. Arrays were revealed with chemoluminiscence and spots were quantified by densitometry in G-BOX system. Differences between arrays between pterygium and healthy conjunctiva were analyzed by studen-t test; p<0.05 was considered as statistically significant.
Results: :
Proteome apoptosis arrays analyzed 35 proteins, seven of them showed differences between pterygium and healthy conjunctiva. Pro-caspase 3, clusterin, cytochrome c, Fas/TNFRSF6, Hsp-70 and SMAC/DIABLO were overexpressed in pterygium in comparison to healthy conjunctiva (p<0.05); meanwhile catalase showed down regulation in pterygium as compared to conjunctiva (p<0.05).
Conclusions: :
Although several pro-apoptotic proteins were overexpressed in pterygium such as cytochrome c, Fas/TNFRSF6, SMAC/DIABLO; Hsp-70, which is an anti-apoptotic protein, was also overexpressed. It has been reported that Hsp-70 inhibits the apoptosis pathway between cytochrome c release and caspase 3 activation, the acummulation of pro-caspase 3 could be as a result of this inhibition. Taken together these results suggest that apoptosis in pterygium is inhibited in comparison to healthy conjunctiva. This study reveals for the first time a novel mechanistic phenomenon to explain an anti apoptosis effect at primary pterygium.
Keywords: pterygium • apoptosis/cell death • proteomics