[Rna content of gerbil hepatocytes after the flight aboard space platform Foton-M3]

Area of Science:

• Hepatocyte biology
• Space biology
• Histology and histochemistry

Background:

• Hepatocyte size and RNA content are key indicators of liver function.
• Understanding cellular responses to spaceflight is crucial for astronaut health.

Purpose of the Study:

• To compare hepatocyte cytoplasm area and RNA content in gerbils under different experimental conditions: vivarium control, modeled space flight, and actual orbital flight.
• To investigate the zonal distribution of these cellular parameters within hepatic lobes.

Main Methods:

• Histological and histochemical analyses of gerbil liver tissues.
• Cytometric and cytophotometric measurements using an image analyzer (Video-7-Test-Morpho).
• Assessment of hepatocyte cytoplasm area and RNA content (via cytoplasm basophilia) across central, intermediate, and peripheral liver zones.

Main Results:

• In vivarium controls, largest hepatocytes were in intermediate and central zones; highest RNA content was in binucleate hepatocytes of the intermediate zone.
• Synchronous controls showed hepatocyte enlargement, particularly in the peripheral zone, with uniform RNA content across zones.
• Space flight led to greater cytoplasm enlargement than observed in vivarium controls, with a significant decrease in RNA content throughout the liver parenchyma compared to both control groups.

Conclusions:

• Space flight induces significant alterations in hepatocyte morphology and cellular metabolism.
• The observed decrease in RNA content suggests impaired protein synthesis or other RNA-dependent cellular processes in hepatocytes post-flight.
• Findings underscore the profound effects of space environments on liver cell physiology.