TH and Hyperglycemia: TUNEL-positive nuclei and cells containing positive immunoreactivity for the active form of caspase 3 have been observed in the retina of diabetic rodents during the first 4 weeks of hyperglycemia.31,32 The position of cells containing activated caspase 3 was consistent with bipolar neurons, amacrine cells, and retinal ganglion cells, and their colocalization with the NeuN and tyrosine hydroxylase antigens further supports that these cells were neuronal.33