Abstract
Purpose: :
The goal of this study was to test whether a novel beta-adrenergic receptor agonist can reduce apoptosis and TNFα in vitro. This agent will also be used topically for chronic studies of diabetic retinopathy.
Methods: :
Retinal endothelial cells and Müller cells were cultured in high glucose (25mM) media. Cells were treated with various novel beta-adrenergic receptor agonists at specific dosages and time points. Cells receiving no treatment served as controls. Caspase-3 ELISA and TNF-α ELISAs were performed to evaluate apoptosis and inflammatory markers. Two-month diabetic rats were treated for 4 days with compound 49b, followed by PKA ELISA and CREB Western blotting to optimize the dose of 49b.
Results: :
Compound 49b significantly reduced caspase-3 and TNF-α levels in both cell types. Caspase-3 and TNF-α levels were significantly reduced at 50nM in cultured cells, a dose lower than that of a non-specific beta-adrenergic agonist, isoproterenol. PKA levels were significantly increased in diabetic rats treated with 49b at a dose of 10mM.
Conclusions: :
These results indicate that a novel beta-adrenergic receptor agonist is able to reduce inflammation and cell death, common features of non-proliferative diabetic retinopathy. The topical application of the novel compound is currently being tested in vivo in chronic diabetes at 10mM. We will assess diabetic-like changes at 2 and 8-months following treatment.
Keywords: neurotransmitters/neurotransmitter systems • apoptosis/cell death • inflammation