title: Neural Stem Cell-based Intraocular Administration of Pigment Epithelium-derived Factor Promotes Retinal Ganglion Cell Survival and Axon Regeneration after Optic Nerve Crush Injury in Rat: An Experimental Study.
abstract: BACKGROUND
  Pigment epithelium-derived factor (PEDF) is regarded as a multifunctional protein possessing neurotrophic and neuroprotective properties. PEDF has a very short half-life, and it would require multiple injections to maintain a therapeutically relevant level without a delivery system. However, multiple injections are prone to cause local damage or infection. To overcome this, we chose a cell-based system that provided sustained delivery of PEDF and compared the effect of weekly injections of PEDF and neural stem cell (NSC)-based intraocular administration of PEDF on retinal ganglion cell (RGC) survival and axon regeneration after optic nerve injury.
  
  
  METHODS
  Seventy-two rats were randomly assigned to 3 groups: group with injections of phosphate buffered saline (PBS) (n=24), group with weekly injections of PEDF (n=24), and group with NSC-based administration of PEDF (n=24). Western blot was used to analyze the PEDF protein level 2 weeks after injection. Retinal flat mounts and immunohistochemistry were employed to analyze RGC survival and axon regeneration 2 weeks and 4 weeks after injection. The data were analyzed with one-way ANOVA in SPSS (version 19.0). A P<0.05 was considered significant.
  
  
  RESULTS
  The PEDF protein level in the group with NSC-based administration of PEDF increased compared with that in the groups with injections of PEDF and PBS (P<0.05). The PEDF-modified NSCs differentiated into GFAP-positive astrocytes andβ-tubulin-III-positive neurons. NSC-based administration of PEDF effectively increased RGC survival and improved the axon regeneration of the optic nerve compared with weekly injections of PEDF.
  
  
  CONCLUSIONS
  Subretinal space transplantation of PEDF-secreting NSCs sustained high concentrations of PEDF, differentiated into neurons and astrocytes, and significantly promoted RGC survival and axon regeneration after optic nerve injury.
authors: Department of Neurosurgery, Zhumadian Central Hospital, Zhumadian, China.
authors: Wei-Min
authors: WM
authors: Zhang
authors: Department of Medical Administration, Zhumadian Central Hospital, Zhumadian, China.
authors: Zhi-Ren
authors: ZR
authors: Zhang
authors: Department of Neurosurgery, Zhumadian Central Hospital, Zhumadian, China.
authors: Yong-Gang
authors: YG
authors: Zhang
authors: Department of Neurosurgery, Zhumadian Central Hospital, Zhumadian, China.
authors: Yan-Sheng
authors: YS
authors: Gao
keywords: Neural stem cells; Optic nerve; Pigment epithelium-derived factor