Abstract
Abstract: :
Purpose:In our previous study on streptozotocin induced diabetic rat retina, outnumbered neuronal nitric oxide synthase(nNOS) expressing neurons appeared in the outer part of the inner nuclear layer(INL) and marked loss of photoreceptor cells in the outer nuclear layer in the long-term diabetic retina. There must be a close correlation between the two findings. The present study has been conducted to determine the identity of the up-regulated nNOS expressing neurons for a clue. Methods:Sprague-Dawley rats were injected with streptozotocin in dose of 60mg/kg body weight(in 0.05M sodium citrate-HCl buffer, pH 5.5). The animals showing high blood glucose level(over 300mg/dl) were cared for 1, 4, 12, and 24 weeks, respectively. At each time point, the retinas were dissected out and processed for both immunoelectron microscopy by using rabbit anti-nNOS antibody and double immunocytochemistry using anti protein kinase C-α(PKC-α)antibody, a marker of rod bipolar cells. Results:In the immunoelectron microscopic observation of the diabetic rat retina, nNOS expressing neurons in the outer part of the INL showed morphological characteristics of bipolar cells. In the double immunocytochemistry for identifying whether the property is of rod or of cone bipor cells, all nNOS expressing bipolar cells are not labeled with PKC-α antibody. Conclusion:These findings suggest that the up-regulated nNOS expressing neurons may be one population of rod and cone bipolar cells containing the same specific factor which is responsible for up-regulated NO production to diabetic stimulus.
Keywords: 388 diabetic retinopathy • 491 nitric oxide • 434 immunohistochemistry