title: Changes in the photoreceptor mosaic of P23H-1 rats during retinal degeneration: implications for rod-cone dependent survival.
abstract: OBJECTIVE
  To investigate the spatiotemporal relationship between rod and cone degeneration in the P23H-1 rat.
  
  
  METHODS
  Control Sprague-Dawley (SD) and P23H-1 rats of ages ranging from P30 to P365 were used. Retinas were processed for whole mounts or cross sections and rods and cones were immunodetected. We used newly developed image analysis techniques to quantify the total population of L/M cones (the most abundant cones in the rat) and analyzed the rings of rod-cone degeneration.
  
  
  RESULTS
  In P23H-1 rats, rod degeneration occurs rapidly: first the rod outer segment shortens, at P30 there is extensive rod loss, and by P180 rod loss is almost complete except for the most peripheral retina. The numbers of L/M cones are, at all postnatal ages, lower in P23H-1 rats than in control SD rats, and decrease significantly with age (by P180). Rod and cone degeneration is spatiotemporally related and occurs in rings that appear already at P90 and spread throughout the entire retina. At P180, the rings of rod-cone degeneration are more abundant in the equatorial retina and are larger in the dorsal retina.
  
  
  CONCLUSIONS
  This work describes for the first time that in the P23H-1 rat, rod and cone degeneration is spatiotemporally related and occurs in rings. Cone loss follows rod loss and starts very soon, even before P30, the first age analyzed here. The characteristics of the rings suggest that secondary cone degeneration is influenced by retinal position and/or other intrinsic or extrinsic factors.
authors.affiliation: Laboratorio de Oftalmología Experimental, Facultad de Medicina, Universidad de Murcia, Campus de Espinardo, Murcia, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: García-Ayuso
authors.forename: Arturo
authors.initials: A
authors.lastname: Ortín-Martínez
authors.forename: Manuel
authors.initials: M
authors.lastname: Jiménez-López
authors.forename: Caridad
authors.initials: C
authors.lastname: Galindo-Romero
authors.forename: Nicolás
authors.initials: N
authors.lastname: Cuenca
authors.forename: Isabel
authors.initials: I
authors.lastname: Pinilla
authors.forename: Manuel
authors.initials: M
authors.lastname: Vidal-Sanz
authors.forename: Marta
authors.initials: M
authors.lastname: Agudo-Barriuso
authors.forename: María P
authors.initials: MP
authors.lastname: Villegas-Pérez
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D007150:Immunohistochemistry; D055355:Opsins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D055647:Rats, Transgenic; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology*; D012162:Retinal Degeneration / Q000235:genetics / Q000473:pathology*; D017948:Retinal Rod Photoreceptor Cells / Q000166:cytology*; D012243:Rhodopsin / Q000235:genetics
chemical_list: D055355:Opsins; D012243:Rhodopsin
keywords: P23H; automated quantification; opsin; retinitis pigmentosa; rhodopsin; rings