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S. Kalakonda, R.K. Srivastava, S.D. Varma; Apoptotic and Necrotic Nuclear Changes in Galactose Cataract . Invest. Ophthalmol. Vis. Sci. 2003;44(13):3473.
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Purpose: Previous studies have emphasized on the role of several cytosolic changes in the lens cells associated with the formation of cataracts in galactosemia. The objective of the present studies was to examine the possibility of simultaneous necrotic and apoptotic degradation in the nuclear region of the cataract associated lens cells, and to determine the role of such changes in sugar cataract formation. Methods:Sprague Dawley rats weighing 80-90 g. were maintained on a 50 % galactose diet for 18 days. Subsequently, they were euthanized, eyes enucleated and lenses extracted atraumatically were immediately fixed in buffered 4 % formaldehyde. The fixed tissue was then sectioned and stained with Hemotoxylin-Eosine (H&E) for discerning the status of the overall tissue organization, or with Bis-Benzimide H-33258(Sigma) for specific staining of the nuclei or with the Tunel reagent (Roche cat No # 1 684 817) for detection of the apoptotic changes. Results: As expected, the normal lens showed a well defined organization of the tissue into a single cell layered anterior epithelium followed posteriorly by the cortical and nuclear fiber cells. In the galacosemic lens, the epithelium becomes multilayered. The homogeneity of the anterior cortex also underwent extensive disorganization Characterized by the presence of several nucleated fiber cells. Most importantly, H-33258 staining and fluorescence microscopy showed that the nuclear volume was much greater than normal, indicating significant hydration. They also lost their structural contour. Tunnel assay detected presence of significant apoptosis in such nuclei. Such apoptotic change was noticed also in the anterior most epithelial cells. Conclusion: These results demonstrate that, in addition to the previously known cytosolic changes in the lens cells, galactose cataract formation is also associated with significant aberrations in the nuclear structure and function. The nuclei are apoptotic as well as necrotic. The mechanism of these alterations remains unknown. The possibility that they may be caused by the sugar induced oxidative stress is under investigation. The prevention of galactose cataracts by anti-oxidants such as pyruvate has been recently published (Free Rad. Res. 30, 253-263, 1998).
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