The Effect Of Simulated Weightless Test On Human Oral Microecosystem Health

ObjectiveTo observe the effection of simulated weightless test on human oral microecosystem health,In order to make a basic research on astronaut’s mouth cleaning technologyhe of medium-long flight and Aerospace medicine preparation MethodsFourteen healthy male were recruited and exposed to-6°head down tilt bed rest(HDT)for 30 days for simulating status of weightlessness.Another comparible group of 14 healthy male was selected as blank contrtrol.Rest salivary specimens were collected at the time points of 3 days before HDT.Day 3,Day 15,Day 30 and 3 day post-weightlessness recovery period.The salivary volumes,SIgA and tooth bacterial colony concentrations of each participate were examined and the salivary flow rates and SIgA secretary rates were then calculated respectively.Cultivate S.mutans, Blastomyces albicans. lactisbacillus, and all bacteria with selectivity culture media and blood dish.Separately accout CFU/ml and analyse by statistics. Results1.Level of salivary volumes at HDT Day 3(7.1±0.8ml/10min) was significantly lower comparing to pr-HDT (8.5±1.0ml/10min) (P<0.01). Day 15(8.0±0.7 ml/10min) was lower than pr-HDT(P<0.05). Day 30 (8.3±0.7 ml/10min) and 3 day post-PHD (8.2±0.6 ml/10min) were no changes.2.The concentrations and secretary rates of SIgA at HDT Day 3(122±81ng/ml;83±54ng/min),Day 15(192±183ng/ml;148±137ng/min) and Day 30 were (168±183ng/ml;135±144ng/min) significantly higher than that of pre-HDT and blank controls (P<0.01, P<0.05).There were no differences of SIgA concentrations at 3 days post-HDT,pre-HDT and blank controls.3.There was an marked increase of lactisbacillus[log (CFU/ml+1)]in tooth bacterial colony on Day 3,Day 15,Day 30 (2.52±1.14; 2.59±1.13; 2.61±1.23)vs pre-HDT(p<0.05);Amount of S.mutans (3.79±0.90) was reduced on the 15th day during HDT.there were no distinct difference of Blastomyes albicans and all bacteria. ConclusionsChanges caused by simulated weightlessness environment for performance.1) Saliva flow change show stress-to-the process of recession, Early reduction, and then gradually restored2) Human oral mucosal immunity of SIgA was enhanced.3)Dental plaque in environmental change,Acid bacteria increase.It may promote caries damage occurred.