N-Methyl-N-Nitrosourea-Induced Photoreceptor Degeneration Is Inhibited by Nicotinamide via the Blockade of Upstream Events before the Phosphorylation of Signalling Proteins

Figure 1

Histological retinal examination seven days after MNU or MNU/NAM administration. All retinal layers were clearly observed in control retinas (a). Photoreceptor cells were completely degenerated in the retinas of MNU injected rats (b), whereas they were rescued from the degeneration by subcutaneous NAM injection (c). Scale bar is indicative of 50 micrometres. The thickness of whole retina ((d) from ILM to RPE) and the ONL (e) were measured at 0.5 mm interval between the superior (+) and inferior (-) part. Data are shown as mean ± standard error (n = 4–8). MNU: N-methyl-N-nitrosourea; NAM: nicotinamide; OCT: optical coherence tomography; ONL: outer nuclear layer; PRE: retinal pigment epithelium; and ILM: internal limiting membrane.