Effect of simulated microgravity on salivary and serum oxidants, antioxidants, and periodontal status

Microgravity is associated with an increase in peroxidative damage. The effect is more pronounced after long-duration space flights and can even last for several weeks after landing. The objective of the study is to determine the influence of simulated microgravity on the periodontal status and salivary and serum oxidant/antioxidant status of the body in simulated microgravity (-6° head-down-tilt [HDT) bed rest).

Twenty healthy male volunteers were studied before and after 60 days of simulated microgravity (-6° HDT bed rest). We measured salivary and serum oxidative markers, such as malondialdehyde (MDA), 8-oxo-7,8 dihydro-2 deoxyguanosine (8-OHdG), and vitamins C and E, and clinical periodontal parameters (probing depth [PD] and clinical attachment level [CAL]).

Serum and salivary vitamin C and E concentrations were significantly decreased, whereas MDA and 8-OHdG levels were significantly increased after 60 days of simulated microgravity. Serum and salivary markers showed a strong and significant correlation. CAL and PD were higher but not statistically significant in simulated microgravity.

This study suggests that oxidative stress in the microgravity environment was increased but did not significantly influence periodontal parameters after 2 months. Also, this study indicates the possibility that the findings may have a broader clinical relevance to patients on bed rest or who are physically inactive. Studies on larger patient samples and follow-up for a longer time are required to verify the relationship between antioxidant status in the space microgravity condition and periodontal health.