Cellular death in retinas of DR rats. The top images depict hematoxylin and eosin-stained cryosections of retinas of control (A) and DR rats (B) 3 months after onset of diabetes. The cells of the GCL are uniformly distributed in the control rats, whereas there is shrinkage and cell death occurring in the GCL (arrowhead) in DR rats. The bottom images show TUNEL staining of retinas of control (C) and DR rats (D) 3 months after onset of diabetes. DNA damage was apparent in the GCL and INL in the DR rats (arrow) but not in the AMC. RGCL, retinal ganglionic cell layer; INL, inner nuclear layer; ONL, outer nuclear layer. Scale bar = 50 μ.