Microgravity in the STS-29 Space Shuttle Discovery affected the vestibular system of chick embryos

C. D. Fermin, D. Martin, T. Jones, J. Vellinger, M. Deuser, P. Hester, R. Hullinger

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Out of 32 embryos flown (16 @ E2 + 16 @ E9) for 5 days, 16 survived. All sixteen E2 were dead at landing. Eight were opened and eight were incubated at 1.0G. Autopsy showed that 4 E2 survived over 24 hours in space. Eight E14 hatched without anatomical malformations, and 8 E14 were fixed. The height of the macular epithelia was 31 μm (mean) in control and 26 μm in flight chicks. The cross-sectional area of macular nuclei of control was 17 μm2 for hair cells and 14 μm2 in supporting cells. In flight, cross-sectional area was 17 μm2 in hair cells and 15 μm2 in supporting cells (n = 250). The shape factor of cartilage cells (1.0 = perfect circle) between control (mean = 0.70) and flight (mean = 0.72), and the area of cartilaginous cells between controls (mean = 9 μm2) and flight (mean = 9 μm2) did not differ (n = 300). The nuclei of support cells were closer to the basement membrane in flight than in control chicks. The immunoreactivity of otoconia with anti keratan, fibronectin or chrondroitin sulfate was not different between flight and control ears. There were more afferent fibers inside the macular epithelia of flight (p < 0.05) than control. Three of 8 flight animals had elevated vestibular thresholds (VT), with normal mean response amplitudes and latencies. Modified afferent innervation patterns requiring weeks to compensate are sufficient to elevate VT, and should be investigated further. Other reversible (sublethal) microgravity effects on sensory epithelia (vacuoles, swelling, etc) require quantification.

Original languageEnglish (US)
Pages (from-to)407-426
Number of pages20
JournalHistology and Histopathology
Issue number2
StatePublished - 1996
Externally publishedYes


  • STS-29
  • color thresholding
  • embryos
  • microgravity
  • space flight
  • vestibular system

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology


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