The Mice Drawer System (MDS) Tissue Sharing program was the longest
rodent space mission ever performed. It provided 20 research teams with
organs and tissues collected from mice having spent 3 months on the
International Space Station (ISS). Our participation to this experiment
aimed at investigating the impact of such prolonged exposure to extreme
space conditions on mouse skin physiology.
were maintained in the MDS for 91 days aboard ISS (space group (S)).
Skin specimens were collected shortly after landing for morphometric,
biochemical, and transcriptomic analyses. An exact replicate of the
experiment in the MDS was performed on ground (ground group (G)).
A significant reduction of dermal thickness (−15%, P=0.05) was observed in S mice accompanied by an increased newly synthetized procollagen (+42%, P=0.03),
likely reflecting an increased collagen turnover. Transcriptomic data
suggested that the dermal atrophy might be related to an early
degradation of defective newly formed procollagen molecules.
Interestingly, numerous hair follicles in growing anagen phase were
observed in the three S mice, validated by a high expression of specific
hair follicles genes, while only one mouse in the G controls showed
growing hairs. By microarray analysis of whole thickness skin, we
observed a significant modulation of 434 genes in S versus G mice. A
large proportion of the upregulated transcripts encoded proteins related
to striated muscle homeostasis.
suggest that a prolonged exposure to space conditions may induce skin
atrophy, deregulate hair follicle cycle, and markedly affect the
transcriptomic repertoire of the cutaneous striated muscle panniculus