title: Effects of high salt-exposure on the development of retina and lens in 5.5-day chick embryo.
abstract: OBJECTIVE
  Excess maternal salt intake during pregnancy may alter fetal development. However, our knowledge on how an increased salt intake during pregnancy influences fetal eye development is limited. In this study, we investigated the effects of high-salt treatment on the developing eyes in chick embryos, especially focusing on the development of the retina and the lens.
  
  
  METHODS
  5.5-day chick embryos were exposed to 280mosm/l (n=17), or 300mosm/l (n=16) NaCl. The treated embryos were then incubated for 96 hours before they were fixed with 4% paraformaldehyde for H&E staining, whole-mount embryo immunostaining and TUNEL staining. BrdU and PH3 incorporation experiments were performed on the chick embryos after high-salt treatment. RT-PCR analyses were conducted from chick retina tissues.
  
  
  RESULTS
  We demonstrated that high-salt treatment altered the size of eyes in chick embryos, induced malformation of the eyes and impaired the development of the lens and the retina. We found an impaired expression of Paired box 6 (PAX6) and neuronal cells in the developing retina as revealed by neurofilament immunofluorescent staining. There was a reduction in the number of BrdU-positive cells and PH3-positive cells in the retina, indicating an impaired cell proliferation with high-salt treatment. High-salt treatment also resulted in an increased number of TUNEL-positive cells in the retina, indicating a higher amount of cell death. RT-PCR data displayed that the expression of the pro-apoptotic molecule nerve growth factor (NGF) in chick retina was increased and CyclinD1 was reduced with high-salt treatment. The size of the lens was reduced and Pax6 expression in the lens was significantly inhibited. High salt-treatment was detrimental to the migration of neural crest cells.
  
  
  CONCLUSIONS
  Taken together, our study demonstrated that high-salt exposure of 5.5-day chick embryos led to an impairment of retina and lens development, possibly through interfering with Pax6 expression.
authors.affiliation: Key Laboratory for Regenerative Medicine of the Ministry of Education, Division of Histology and Embryology, Medical College, Guangzhou, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Chen
authors.forename: Guang
authors.initials: G
authors.lastname: Wang
authors.forename: Xiao-yu
authors.initials: XY
authors.lastname: Wang
authors.forename: Zheng-lai
authors.initials: ZL
authors.lastname: Ma
authors.forename: You-peng
authors.initials: YP
authors.lastname: Chen
authors.forename: Manli
authors.initials: M
authors.lastname: Chuai
authors.forename: Karoline
authors.initials: K
authors.lastname: von Websky
authors.forename: Berthold
authors.initials: B
authors.lastname: Hocher
authors.forename: Xuesong
authors.initials: X
authors.lastname: Yang
mesh_terms: D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D002642:Chick Embryo; D017931:DNA Primers; D004305:Dose-Response Relationship, Drug; D005124:Eye Abnormalities / Q000139:chemically induced; D005136:Eye Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D007908:Lens, Crystalline / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D016900:Neurofilament Proteins / Q000378:metabolism; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D012160:Retina / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012965:Sodium Chloride / Q000008:administration & dosage*
chemical_list: D017931:DNA Primers; D005136:Eye Proteins; D018398:Homeodomain Proteins; D016900:Neurofilament Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; D012965:Sodium Chloride