Increased levels of miR-210 in human saliva induced by acute hypobaric hypoxia

Objective: This study investigated the effects of acute hypobaric hypoxia (HH) on miR-210 levels in the blood, saliva, and brain, in a high altitude-simulating cabin environment. qRT-PCR was used to detect miR-210 in cerebrospinal fluid, brain tissue, blood and saliva before and after acute HH exposure. This study aimed to evaluate the role of miR-210 as a noninvasive marker of acute HH. Methods: Sprague-Dawley rats were randomly assigned to the experimental group and were placed in a hypobaric chamber to mimic a high altitude of 5000 m (12.95% O-2) for 0.5, 1, and 2 h. The control group rats were exposed to corresponding normoxic conditions. At the indicated time points, brain tissue homogenates, cerebrospinal fluid and blood were collected from the rats, and plasma and saliva were collected from the human subjects. Eight healthy human subjects were studied at baseline (80 m), during acute HH at a high altitude (4300 m) for 40 min and upon return to baseline (80 m). All work involving human participants was approved by the Ethics Committee of the Institute of Psychology, Chinese Academy of Sciences (ethics review approval number: H19008). Results: Acute HH led to increased miR-210 levels in the cerebrospinal fluid, plasma and saliva but decreased miR-210 levels in brain tissue and blood cells. Conclusion: This study confirmed that the amount of circulating miR-210 in cerebrospinal fluid, plasma and saliva markedly increases under acute HH, suggesting that circulating miR-210 may be a biomarker of acute HH. In particular, evaluation of salivary miR-210 represents a rapid, noninvasive test of acute HH-related diseases with important clinical significance for diagnosis and disease progression monitoring.