Adaptive response to stress of acute myocardial infarction leads to apoptosis of retinal cells of rats

Evidence indicates that adaptive responses to systemic stress occur in retina, as indicated by the changes in sympathetic and sensory afferent neurotransmitters in the retina when under stressful stimulation, such as acute myocardial infarction. The aim of this study was to investigate the potential association of the adaptive responses with retina injury, indicated as apoptosis of retinal cells of the rats suffering from acute stress evoked by coronary artery occlusion (CAO). The apoptotic rate of retinal cells and activity of caspase-3 in retina were examined and analyzed over 6 h of CAO using TUNEL and caspase assay. It was observed that the rate of apoptosis of the retinal cells was significantly increased to 16.8%±6% (n=10, vs. control, p<0.05) and 26.9%±6.1% (n=10, vs. control, p<0.05), mainly in ganglion cells of the retina, at 3 and 6h of CAO, respectively. And the activity of caspase-3 was also up-regulated to 2.16±0.77 at 3h of CAO (vs. 1.00±0.32 of the control, p<0.05, n=10) and 2.72±1.11 at 6h of CAO (vs. 1.37±0.76 of control, p<0.05, n=10). The findings may indicate that the adaptive responses to acute stressful simulation, such as acute myocardial infarction, could result in retinal cell injury, presented as increase in apoptosis of retinal cells.