Effects of spaceflight on trabecular bone in rats

Area of Science:

• Space biology
• Skeletal physiology

Background:

• Spaceflight poses risks to bone health.
• Understanding microgravity effects on growing bone is crucial.

Purpose of the Study:

• To investigate the effects of spaceflight on trabecular bone in growing rats.
• To assess bone changes during and after spaceflight.

Main Methods:

• Growing male Wistar rats were flown on the COSMOS 1129 biosatellite for 18.5 days.
• Bone mass, marrow fat content, osteoblast, and osteoclast populations were analyzed.

Main Results:

• Spaceflight decreased mineralized tissue mass and increased bone marrow fat in tibiae and humeri.
• Osteoblast numbers decreased, while osteoclast numbers remained unchanged.
• Most skeletal alterations resolved within 29 days postflight, except for tibial bone mass.

Conclusions:

• Spaceflight appears to inhibit bone formation while maintaining resorption.
• The growing rat skeleton exhibits partial recovery after spaceflight exposure.