Effects of simulated microgravity conditions on carrageenin-induced oedema in rat

The effects of simulated microgravity conditions, using a three-dimensional clinostat (Random Positioning Machine, RPM), on carrageenin-induced paw oedema in rats as a model of local inflammation were evaluated. RPM-exposed animals showed a significant reduction of oedema and a more pronounced decrease in body weight with respect to control groups. Moreover, aspirine (ASA) treatment, an anti-inflammatory agent, on RPM-exposed rats did not exhibit any activity after carrageenin challenge with respect to RPM control, on the contrary, ASA elicited a significant inhibition of oedema with respect to control animals on the ground. ASA activity on RPM could be prevented by RPM-induced anti-oedematous effect. RPM-induced anti-oedematous effect did not reversed by pre-treatment with the non-selective glucocorticoid receptor antagonist, mifepristone ruling out the supposed influence of an increase of cortisol release during the RPM treatment.