Abstract
Abstract: :
Purpose:In the ocular disease glaucoma, the most frequent and important association is that of elevated intraocular pressure(IOP), either acute or chronic. This disease is characterized by the progressive loss of retinal ganglion cells (RGCs). But little know regarding the interaction between pressure and loss RGCs at the level of the cell. This study investigated the effect elevated hydrostatic pressure in vitro on RGCs cell line (RGC–5). Methods: RGC–5 were subjected to pressure condition in pressure chambers. Pressure conditions were within physiological limits 100 mmHg over atmospheric pressure. Cell viability was detected by cell morphology changes and MTT assay. The change of protein pattern was investigated by using of proteomics method. Proteins were separated by 2–D gel electrophoresis(pH3–10: 8–18% gradient). Protein spots were cut from coomassie blue–stained gels, digest with trypsin, and identified by using a MALDI mass spectrometry. Results: This study subjected RGC–5 to raised pressure and durations similar to those found in acute glaucoma and found an inhibition of cell proliferation and an increase in neuronal apoptosis under these conditions. A proteomics–based approach results showed RGC–5 cellular proteins pattern alteration after raising pressure. Compared to normal control group, pressured cell have higher levels of glyceraldehydes 3–phosphate dehydrogenase(GAPDH), pyruvate kinase, chloride intracellular channel protein 4, tubulin alpha/beta chain, galectin–1, GPIIIA, ubiquitin–activating enzyme E1, but lower levels of nuclear ribonucleoprotein H and elongation factor 2. The amount of GAPDH was 3 fold elevated in RGC–5 subjected to pressure for 24hr. Furthermore, immunocytochemical result reveal that GAPDH accumulates densely in the nucleus as well as GAPDH overexpression. Conclusions:This study showed that pressure alone may act as a stimulus for apoptosis in retinal ganglion cell culture. This also suggests that elevated pressure, such as those found in acute glaucoma, may stimulate apoptosis. We would suggest the possibility that apoptosis of RGC–5 associated with raised pressure induced overexpression and translocation of GAPDH, which may participated in the pathogenesis of some neurodegenerative disease.
Keywords: intraocular pressure • ganglion cells • proteomics