title: Temporal and spatial characteristics of cone degeneration in RCS rats.
abstract: OBJECTIVE
  The temporal and spatial characteristics of cone degeneration in the Royal College of Surgeons (RCS) rat were studied to provide information for treatment strategies of retinitis pigmentosa.
  
  
  METHODS
  Nonpigmented dystrophic RCS rats (RCS) and pigmented nondystrophic RCS rats (controls) were used. Cone processes were visualized with peanut agglutinin (PNA).
  
  
  RESULTS
  Cone development appears to have been completed by postnatal day 21 (P21) in both the RCS and control rats. Signs of cone degeneration were obvious by P30, with shorter outer segments (OSs) and enlarged inner segments (ISs). At that time, 81.7% of the cones retained stained ISs. The rate of IS density decline was slower in the peripheral, nasal, and superior retina, and only 43.6% of the cones with ISs were present at P45. By P60, PNA-labeled cone ISs were distorted and restricted to the peripheral retina, and by P90, few cone pedicles were detected.
  
  
  CONCLUSIONS
  Our findings indicate that therapeutic strategies aimed at rescuing cones in the degenerating retina should be applied before P21 and no later than P45 while substantial numbers of cones retain their ISs. Either the middle or peripheral regions of the nasal and superior retina are the best locations for transplantation strategies.
authors.affiliation: Southwest Hospital, Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, People's Republic of China.
authors.forename: Yan Ming
authors.initials: YM
authors.lastname: Huang
authors.forename: Zheng Qin
authors.initials: ZQ
authors.lastname: Yin
authors.forename: Kang
authors.initials: K
authors.lastname: Liu
authors.forename: Shu Jia
authors.initials: SJ
authors.lastname: Huo
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development; D006651:Histocytochemistry; D019887:Peanut Agglutinin; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000254:growth & development / Q000473:pathology; D017949:Retinal Cone Photoreceptor Cells / Q000473:pathology*; D012162:Retinal Degeneration / Q000473:pathology*; D055211:Retinal Photoreceptor Cell Inner Segment / Q000473:pathology; D055214:Retinal Photoreceptor Cell Outer Segment / Q000473:pathology; D013997:Time Factors
chemical_list: D019887:Peanut Agglutinin