Purpose: To investigate whether reduced Sox9 function exerts neuroprotection in light-induced retinal damage in rats and to explore the potential mechanism behind it.
Methods: Retinal light damage was used as a model for retinal degeneration. Two weeks before light damage in adult Sprague Dawley (SD) rats, the Sox9-shRNA lentiviral vector was intravitreally injected. On days 3, 7, and 14, retinal function was assessed using electroretinography (ERG), and the thickness of the outer nuclear layer (ONL) was measured in hematoxylin and eosin (HE) stained sections. The protein levels of glial fibrillary acidic protein (GFAP), vimentin, nestin, and chondroitin sulfate proteoglycans (Cspgs), which are related to gliosis and extracellular matrix (ECM) remodeling, were observed using western blot analysis. The expression of GFAP was further evaluated by immunohistochemistry.
Results: On days 3, 7, and 14 after light damage, the thickness of the ONL and the amplitudes of the ERG waves were significantly better preserved in the Sox9-shRNA group when compared with the control group. The protein levels of GFAP, vimentin, nestin, and Cspgs were significantly downregulated in the Sox9-shRNA group. Furthermore, the staining intensity and the spatial distribution of GFAP in the retinas were also obviously attenuated at every studied time point.
Conclusions: Intravitreal injection of the Sox9-shRNA lentiviral vector preserved rat retinal morphology and function after light damage and downregulated GFAP, vimentin, nestin, and Cspgs, which are related to Müller cell gliosis and ECM remodeling. The results indicate that Sox9 might be a potential therapeutic target for retinal degenerative diseases.
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