Effects Of Hypoxia Exposure At Different Time On The Structure And Function Of Erythrocytes In Rats

BackgroundHigh altitude polycythemia(HAPC)is the most common long-term high altitude sickness among people living in the plateau.The essence of HAPC is the excessive increase of erythrocytes under the action of long-term hypoxia,which leads to the increase of blood viscosity and microcirculation disturbance,which in turn aggravates the hypoxia of tissues and cells and causes headache,dizziness and other symptoms.It is severe for the patients losing the abilities to work and live.Worse still,sudden death due to vascular embolism is possible.It has been reported that altitudes,duration of exposure to hypoxia,physical activity,daily water intake and body mass index are the main factors that affect HAPC.The factors including altitudes and duration of hypoxia exposure are more significant.As the altitude rises,the incidence rises linearly.Hypoxia can upregulate hypoxia-inducible factor(HIF),stimulate the massive secretion of erythropoietin(EPO),such as liver and kidney,and induce erythropoietic proliferation of bone marrow after binding with EPO receptor,resulting in an increase in the number of erythrocytes in the blood.In the past,little attention was paid to the changes of the structure and function of erythrocytes.However,the changes of erythrocyte structure and function in hypoxia environment were of great significance for clinical and scientific research.ObjectiveTo investigate the effects of hypoxia exposure on the structure and function of erythrocytes in rats at different time.MethodsForty rats were randomly divided into 5 groups: normal control group(C),1 week hypoxia group(H1 group),2 week hypoxia group(H2 group),3 week hypoxia group(H3 group)and 4 week hypoxia group(H4 group),8 per a group.The rats in H groups were placed in the simulated 5800 m of high altitude in a hypobaric chamber at different time.Then values of blood,the erythrocyte deformation indexes,erythrocyte osmotic fragmentation,erythrocyte oxygen dissociation,erythrocyte apoptosis and bone marrow biopsy were fulfilled.ResultsCompared with the normal control group,the red blood cell count(RBC),hemoglobin(HB),mean corpuscular volume(MCV),mean corpuscular hemoglobin(MCH)significantly increased(P <0.01);phosphatidylserine(PS)exposure of erythrocytes increased;P50 increased(p <0.05).Bone marrow erythroid proliferation increased.Erythrocyte deformation indexes and erythrocyte osmotic fragility decreased significantly(p <0.01).In addition,oxygen dissociation curve shifted to the right.ConclusionIn the early stage of hypoxia,compared with the normal control group,the changes of structure and function could increase the oxygen supply to the tissue and be conducive to adapt to the plateau.H3 became a turning-point of the effects.However,with the extension of time,excessive intravascular retention of changed erythrocytes easily led to thrombosis,microcirculation disorder and aggravating tissue hypoxia.