title: Effect of long-term weightlessness on retina and optic nerve in tail-suspension rats.
abstract: OBJECTIVE
  To evaluate the effect of long-term weightlessness on retina and optic nerve in tail-suspension (TS) rats.
  
  
  METHODS
  A stimulated weightlessness model was established by suspending rats' tail. After 12wk, the ultrastructure and the number of optic nerve axons were observed by transmission electron microscope. The number of survival retinal ganglion cells (RGCs) was calculated by fluorescent gold retrograde labeling. Retina cells apoptosis was detected by TUNEL staining. The function of optic nerve and retina was evaluated by the visual evoked potential (VEP) and oscillatory potentials (Ops).
  
  
  RESULTS
  The optic nerve axons were swollen and sparsely aligned, and the lamellar separation and myelin disintegration occurred after 12wk in TS rats. The density of optic nerve axons was 32.23±3.92 (vs 37.43±4.13, P=0.0145), the RGCs density was 1645±46 cells/mm(2) (vs 1867±54 cells/mm(2) P=0.0000), the incidence rate of retinal cells apoptosis was 5.38%±0.53% (vs 4.75%±0.54%, P=0.0238), the amplitude of VEP-P100 was 15.43±2.14 µV (vs 17.67±2.17 µV, P=0.0424), the latency of VEP-P100 was 69.05±5.34ms (vs 62.43±4.87ms P=0.0143) and the sum amplitude of Ops was 81.05±8.34 µV (vs 91.67±10.21 µV, P=0.0280) in TS group and the control group, respectively.
  
  
  CONCLUSIONS
  Long-term weightlessness can induce the ultrastructural changes and functional depress of the optic nerve, as well as retinal cell damages in TS rats.
authors.affiliation: Chinese PLA General Hospital, Beijing 100039, China; Department of Ophthalmology, the 306th Hospital of PLA, Beijing 100101, China.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Zhao
authors.affiliation: Department of Ophthalmology, the 306th Hospital of PLA, Beijing 100101, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Ophthalmology, the 306th Hospital of PLA, Beijing 100101, China.
authors.forename: Lian-Na
authors.initials: LN
authors.lastname: Hu
authors.affiliation: Institute of Microbiology, Chinese Academy of Science, Beijing 100101, China.
authors.forename: Jing-Nan
authors.initials: JN
authors.lastname: Liang
authors.affiliation: Department of Ophthalmology, the 306th Hospital of PLA, Beijing 100101, China.
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Shi
authors.affiliation: Department of Ophthalmology, the 306th Hospital of PLA, Beijing 100101, China.
authors.forename: Chuang
authors.initials: C
authors.lastname: Nie
authors.affiliation: Department of Ophthalmology, the 306th Hospital of PLA, Beijing 100101, China.
authors.forename: Chang-Yu
authors.initials: CY
authors.lastname: Qiu
authors.affiliation: Anhui Medical University, Hefei 230000, Anhui Province, China.
authors.forename: Xin-Shuai
authors.initials: XS
authors.lastname: Nan
authors.affiliation: Department of Ophthalmology, the 306th Hospital of PLA, Beijing 100101, China; Third Military Medical University, Chongqing 400038, China.
authors.forename: Yu-Xin
authors.initials: YX
authors.lastname: Li
authors.affiliation: Department of Ophthalmology, the 306th Hospital of PLA, Beijing 100101, China.
authors.forename: Fu-Lin
authors.initials: FL
authors.lastname: Gao
authors.affiliation: Department of Ophthalmology, the 306th Hospital of PLA, Beijing 100101, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: The First hospital of Jilin University, Changchun 130021, Jilin Province, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Department of Ophthalmology, the 306th Hospital of PLA, Beijing 100101, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Luo
keywords: optic nerve; retina; tail suspension; weightlessness