title: Efficacy of Rho-kinase inhibition in promoting cell survival and reducing reactive gliosis in the rodent retina.
abstract: OBJECTIVE
  To analyze the outcomes of Rho-kinase (ROCK) inhibition on retinal cell survival and glial reactivity under adverse conditions.
  
  
  METHODS
  Organotypic cultures of mouse retinas were incubated with the specific ROCK-inhibitor H-1152P for 24 to 48 hours under serum deprivation. Cell damage was determined by ethidium homodimer-1 uptake and caspase-3 cleavage. Immunohistochemistry and Western blot were performed to detect reactive gliosis and to confirm the specificity of H-1152P. The cytokine profile of the culture medium was analyzed using a membrane-based array. H-1152P was administered intravitreally into rats before optic nerve crush (ONC) and the extent of apoptosis and reactive gliosis was determined after 7 days.
  
  
  RESULTS
  Cell damage in cultured retinas was significantly reduced in response to 1 microM H-1152P, particularly in the ganglion cell layer. This was associated with a decrease in the levels of glial fibrillary acidic protein (GFAP) isoforms and the number of reactive astrocytes, Müller cells, and microglia. The release of proinflammatory cytokines including TNF-alpha, interferon-gamma, and IL-6 was also reduced, which likely contributed to the significantly lower toxicity of the conditioned media collected from retinas incubated with H-1152P. H-1152P (1 microM) suppressed the ROCK-dependent phosphorylation of adducin without a considerable interference with the protein kinase A/C-mediated phosphorylation events, indicating the specificity of the inhibitor for ROCK. H-1152P also resulted in a significant decrease in the extent of apoptosis and reactive gliosis after ONC.
  
  
  CONCLUSIONS
  These results demonstrate the neuroprotective effect of H-1152P-mediated ROCK-inhibition on retinal cells under stress, which may rely partly on the attenuation of glial cell reactivity.
authors.affiliation: University Eye Hospital of the Center of Ophthalmology at the Eberhard-Karls University of Tübingen, Tübingen, Germany. ayseguel.tura@med.uni-tuebingen.de
authors.forename: Aysegül
authors.initials: A
authors.lastname: Tura
authors.forename: Frank
authors.initials: F
authors.lastname: Schuettauf
authors.forename: Philippe P
authors.initials: PP
authors.lastname: Monnier
authors.forename: Karl U
authors.initials: KU
authors.lastname: Bartz-Schmidt
authors.forename: Sigrid
authors.initials: S
authors.lastname: Henke-Fahle