RÉSUMÉ
<p><b>OBJECTIVE</b>To investigate the correlation between the expression of microRNA-451 in red blood cells and chronic mountain sickness(CMS).</p><p><b>METHODS</b>Peripheral blood samples were collected from emigrant CMS patients (28 cases), localized CMS patients (12 case), emigrant healthy people (24 case) and localized healthy people (22 case). The microRNA-451 expression in red blood cells was measured by the RT-PCR. The results combined with the clinical data of patients were analysed.</p><p><b>RESULTS</b>The expression of microRNA-451 in emigrant CMS patients was higher than that in emigrant healthy people (P<0.05); the expression of microRNA-451 in localized CMS patients was higher than that in localized healthy people (P<0.05); the microRNA-451 expression had no statistical difference between emargant and localized healthy people. The level of hemoglobin in CMS patients was positively correlated with the expression of microRNA-451 in red cells (r=0.701).</p><p><b>CONCLUSION</b>There is a certain level of microRNA-451 in healthy people, the expression of microRNA-451 in CMS patients is significantly higher than that in healthy people. MicroRNA-451 may play an important role in the process of chronic mountain sickness.</p>