Suppression of Ganglion Cell Death by PACAP Following Optic Nerve Transection in the Rat

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide that was first isolated from the ovine hypothalamus. PACAP has previously been shown in in vitro experiments to have neuroprotective effects, but its possible application in clinical situations must first be tested in vivo. We examined the protective effect of PACAP against retinal ganglion cell (RGC) death following optic nerve transection in the rat. Fourteen days after sectioning of the optic nerve, the number of RGCs in the vehicle control (untreated: vehicle 0.9% saline, volume 3 μl, injected into the vitreous body) group with axotomized optic nerve was decreased compared with that of intact animals. The number of RGCs in PACAP-treated animals (10 or 100 pM dose added to the vehicle) was significantly increased compared with the vehicle control group. These results indicate that PACAP suppresses ganglion cell death induced by optic nerve transection.