BDNF and glaucoma: After 4 weeks of experimental glaucoma, eyes that received intravitreal AAV-BDNF 38% of RGC were rescued by the AAV-BDNF.[33, 34] Other studies have shown that AAV can mediate transgene expression in RGC for at least 1 year.[35] Isenmann et al.[36] also found protection of the RGCs after Ad-mediated delivery of BDNF, and protection was increased by the combined systemic administration of the free radical scavenger N-tert-butyl-(2-sulfophenyl)-nitrone (S-PBN).