Abstract
Purpose :
Reduced concentration of vitreal Interphotoreceptor-Retinoid-Binding-Protein (IRBP, RBP3) occurs in patients with diabetic retinopathy (DR). As photoreceptors produce IRBP in the retina, it is possible that lowered level of IRBP in diabetes is the result of a reduction of IRBP production from photoreceptors. In the present study, culture retinoblastoma (Y79, rod like) cells were subjected high glucose and hypoxia to study diabetic complication on IRBP expression.
Methods :
Y79 cells were cultured in RPMI Medium on a 24 well plate, coated with Poly-D-Lysine at a density of 65,000 cells per well, in total of 1ml of cell medium. Once cells reached confluency, the cells were treated with low (5.5 mM) and high (30 mM) glucose with and without 300mM of CoCl2 (to induce hypoxia) for 24 and 48 hr. ELISA was used to determine the IRBP concentration in the conditioned media.
Results :
A significant decrease of media IRBP concentration (ng/ml) was noted in cells grown (for 48hr) in high glucose (from 52.0 + 1.0 in LG to 40.5+0.2 in HG). Similarly, [IRBP] from cells grown for 48hr (in high glucose) was also significantly lower than those from cells grown for 24hr (from 50.4+1.0 in 24hr to 40.5+0.2 in 48hr). Hypoxia treatment results in a reduction of [IRBP] from cells grown (for 24hr) in both low and high glucose (48.5+2.0 LG vs 46.0 +1.0 LG & Hypoxia; 50.4 +1.0 HG vs 47.6 + 0.6 HG & Hypoxia).
Conclusions :
High glucose and hypoxia reduced the IRBP concentration in the Y79 conditioned media. In high glucose, an increase incubation time also significantly reduced IRBP production. Shen et al (Int. J. Mol Sci, 18: 533, 2017) reported a similar reduction of IRBP production by Y79 cells in response to hypoxia. However, they reported that high glucose did not result in any significant difference in IRBP production by Y79 cells. The mechanism(s) responsible for the decreased IRBP concentration is under study in our laboratories.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.