Abstract
Purpose :
Although the association between tobacco smoking and open-angle glaucoma has been reported, the mechanism of the impact of smoking on retinal ganglion cells remains controversial.
We studied whether smoking directly injures retinal ganglion cells (RGCs) and the mechanisms of cell death using cigarette smoke extract (CSE) and harvested primary rat RGCs.
Methods :
Primary rat RGCs were harvested from three- or four-day-old newborn rats and exposed to CSE. Cell viability was measured by adenosine 5′-triphosphate (ATP) assay. Apoptosis was evaluated by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) and real-time reverse transcription polymerase chain reaction (RT-PCR) for Bcl-2 family. Autophagy was assessed by Western immunoblots for light chain (LC) 3B.
Results :
After the primary RGCs were exposed to CSE for two hours, cell viability decreased in a dose-dependent manner. In the presence of 0.05% CSE, the RGC viability was 77.68±7.60% compared to the control cells; in the presence of 1.0% CSE, viability was 47.48±2.56% of the control cells. As determined by TUNEL, CSE increased the apoptotic RGCs in a dose-dependent manner. In the presence of 0.05% CSE, the apoptosis was 26.55±1.97% of the control cells; in the presence of 2.5% CSE, it was 41.07±3.75% of the control cells. RT-PCR revealed that exposure to 0.05% CSE resulted in significantly increased expression of Bcl-2 family that regulates apoptosis. Western immunoblots which was used to evaluate autophagy showed that exposure to 0.05% CSE significantly increased the expression of LC3B II.
Conclusions :
CSE directly injures primary RGCs, and both apoptosis and autophagy mechanism seem to be related to this CSE-induced RGCs death.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.