The Effects of the Spaceflight Environment on the Vaginal Mucin Layer of the Mouse

ABSTRACT It has been well documented that spaceflight has adverse effects on many tissues and systems throughout the body. Although this phenomenon is well documented, relatively little research has been done in the area of the female reproductive system. If spaceflight has harmful effects on the female reproductive system, the migration of the human species into space would be greatly compromised. The purpose of this study was to determine the effects of spaceflight on the thickness of the apical mucin layer in the vaginae of mice, as changes in this layer could have detrimental effects on sperm survival and, therefore, a profound impact on the animal’s ability to reproduce. This study examined the thickness of the vaginal mucin lining from female mice that were exposed to 13 days of spaceflight and their concomitant controls. The tissues were stained using a technique commonly used to localize and analyze mucin varieties. The tissue was qualitatively analyzed for the type of mucin produced (i.e., acidic, neutral, acidic/neutral mixture). Further, the tissue was quantitatively analyzed for the amount of mucins produced by measuring the thickness of the mucin layer. The results of this study indicate that spaceflight causes a thickening of the mucin lining of the vaginal canal. The results further indicate being housed in an Animal Enclosure Module also caused a thickening of the vaginal mucin layer — presumably due to internal cage environmental factors — but this effect was not as pronounced as that seen in the spaceflight mice.