Wound healing response to lunar dust exposure in the Rat cornea

Aziza Glass, C. Theriot, C. W. Lam, J. James, S. Zanello

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    1 Scopus citations


    During the Apollo missions, astronauts reported nasal and eye irritation due to lunar dust exposure upon return from lunar extra-vehicular activities. Lunar dust has been reported to have adhesive/abrasive properties. Animal studies show lunar dust is moderate toxic in the lung. However, a recent study on rabbit eyes showed minimal irritancy of the ocular surface from fine (respirable) and coarser unground lunar dust particles. Yet, it is plausible that signaling pathways within the ocular tissue are activated in response to lunar dust exposure, while still being subclinical, evading conventional tests aimed to diagnose change in ocular integrity. To date, no studies have been conducted to assess the effects of lunar dust toxicity on the eyes at the molecular. In a tissue sharing effort derived from a parent lunar dust nose-only inhalation study in which rats were exposed to 0, 20, and 60 mg/m3 of lunar dust for 4 weeks (6 h/d; 5 d/wk), we assessed gene profiles in cornea RNA collected from rats 1 and 7 days after the exposure. Microarray analysis was performed using the Affymetrix GeneChip Rat Genome 230 2.0 Array with Affymetrix Expression Console and Transcriptome Analysis Console used for normalization and secondary analysis. An Ingenuity iReportTM was then generated for canonical pathway identification. Corneas from exposed rats were collected, and the gene expression profiles were compared, at day 1 at high dose and day 7 at low dose, to that in corneas of air-exposed rats. The observed molecular responses in the high dose group suggest a rapid initiation of wound healing/repair process within the cornea. This may be the result of micro-abrasion or epithelial debridement from lunar dust particle contact, which could be aggravated due to the contract of the eyes with the wall of the restraint tube housing the rat during the nose-only exposure. Activation of a gene network implying the actin cytoskeleton signaling response in conjunction with induction of filopodia and membrane ruffles suggest cytoskeleton remodeling to form projection and filopodia that could be used towards phagocytosis and transport of dust particles. The observed response at day 7 focuses more on repopulation of the tissue, differentiation and development, and remodeling of the stromal extracellular matrix. We also see processes suggesting mobilization of neutrophils, apoptosis of stromal cells, change in corneal morphology, and epithelial to mesenchymal transitions. Finally, there is a limited response to oxidative damage within keratocytes. Zhang et al. report activation of inflammation and fibrotic genes in rats exposed to these two lunar concentrations. However, additional studies in which animals not in retraining tubes are required to definitively and fully assess the risk of vision decrements and the responses initiated in the cornea exposed to lunar dust as well as the potential for long-term effects to astronaut health.

    Original languageEnglish (US)
    Title of host publication65th International Astronautical Congress 2014, IAC 2014
    Subtitle of host publicationOur World Needs Space
    PublisherInternational Astronautical Federation, IAF
    Number of pages7
    ISBN (Electronic)9781634399869
    StatePublished - 2014
    Event65th International Astronautical Congress 2014: Our World Needs Space, IAC 2014 - Toronto, Canada
    Duration: Sep 29 2014Oct 3 2014

    Publication series

    NameProceedings of the International Astronautical Congress, IAC
    ISSN (Print)0074-1795


    Other65th International Astronautical Congress 2014: Our World Needs Space, IAC 2014

    ASJC Scopus subject areas

    • Aerospace Engineering
    • Astronomy and Astrophysics
    • Space and Planetary Science


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