Background: Neural apoptosis is generally believed to be mediated by two distinct pathways, caspase-dependant and caspase-independent pathways. This study investigated the apoptotic pathways involved in retinal ganglion cells in acute diabetes in rats.
Methods: Diabetes was induced in male Wistar rats by a peritoneal injection of streptozotocin (STZ). Expression and localization of caspase-3 and apoptosis-inducing factor (AIF) proteins in the retina of diabetic rats was examined by Western blotting and immunohistochemistry analyses. Terminal transferase dUTP nick end labeling (TUNEL) assay and immunofluorescent staining specific for caspase-3 and AIF were applied to analyze for apoptosis of retinal ganglion cells. In addition, a caspase-3 inhibitor DEVD-CHO was injected intravitreally to further determine the apoptotic pathways of retinal ganglion cells triggered in acute diabetes.
Results: Two weeks after induction of diabetes, a significant increase in caspase-3 protein expression and localization occurred in the nerve fiber layer, ganglion cell layer, and inner plexiform layer of the retina. Four weeks after the onset of diabetes, the increase in caspase-3 expression was profound eight weeks postinduction of diabetes (P < 0.05). Meanwhile, no AIF protein expression was detected in this study. In addition, intravitreal administration of the caspase-3 inhibitor DEVD-CHO reduced apoptosis of retinal ganglion cells by its direct inhibitory action on caspase-3.
Conclusion: Caspase-dependent apoptotic pathways may be the main stimulant of STZ-induced retinal ganglion cell apoptosis in acute diabetes.
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Int J Mol Sci
December 2024
Centro de Estudos de Ciência Animal (CECA), Instituto de Ciências, Tecnologias e Agroambiente (ICETA) da Universidade do Porto (UP), Praça Gomes Teixeira, Apartado 55142, 4051-401 Porto, Portugal.
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Department of Ophthalmology, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200080, China.
Ischemic retinopathies are the major causes of blindness, yet effective early-stage treatments remain limited due to an incomplete understanding of the underlying molecular mechanisms. Significant changes in gene expression often precede structural and functional alterations. Transfer RNA (tRNA)-derived small RNAs (tsRNAs) are emerging as novel gene regulators, involved in various biological processes and human diseases.
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Poostchi Ophthalmology Research Center, Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
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Department of Brain Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.
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