Modifications of the digestive tract in rats submitted to an orbital flight aboard the Soviet satellite Cosmos 1129.

Investigations carried out on the digestive tract of rats submitted to an 18 1/2-day orbital flight aboard the Soviet biosatellite Cosmos 1129 revealed that flight produces a reduction of the glycoproteins (GP) of the submaxillary glands, gastric mucosa and the goblet cells of the small and large intestine, the last being the most nonreactive, as well as an augmented staining for leucine-aminopeptidase (LAP) and acid phosphatase (AP). In lamina propria an accumulation of eosinophils was noticed. These changes were more intense than those produced in the groups of rats maintained "synchronous" under environmental conditions similar to flight. On the basis of previous data obtained by various authors and by ourselves on hypokinetic rats from the biosatellite Cosmos 936, it can be concluded that these reactions have a nonspecific, stress character. A stress of restraint applied daily for 2 1/2 hours during a period of 6 days to the animals immediately after landing produced modifications similar to those following flight but more intense, thus underlying the hypothesis of a stress reaction.