ABSTRACT
AIM:To investigate the effects of hypoxia exposure on the structure and function of erythrocytes in rats at different time.METHODS:Male SD rats(n=40)were randomly divided into 5 groups,normal control group,1-week hypoxia group ,2-week hypoxia group ,3-week hypoxia group and 4-week hypoxia group ,with 8 rats per group.The rats in hypoxia groups were placed in the simulated 5800 m of high altitude in a hypobaric chamber for different time.The values of detected blood ,erythrocyte deformation index ,erythrocyte osmotic fragility ,erythrocyte oxygen dissociation ,e-rythrocyte apoptosis and bone marrow biopsy were determined.RESULTS:Compared with normal control group ,the red blood cell count ,hemoglobin content ,mean corpuscular volume and mean corpuscular hemoglobin significantly increased(P<0.01).Eversion rate of phosphatidylserine of erythrocytes increased.Oxygen half-saturation of hemoglobin increased(P<0.05).Bone marrow erythroid proliferation increased.The erythrocyte deformation index and erythrocyte osmotic fra-gility decreased significantly(P<0.01).In addition,oxygen dissociation curves shifted to the right.CONCLUSION:In the early stage of hypoxia ,compared with normal control group ,the changes of erythrocyte structure and function increase the oxygen supply to the tissue and are conducive to adapting to the plateau.However ,with the extension of hypoxia ,ex-cessive erythrocytosis results in thrombosis ,microcirculation disturbance and aggravating tissue hypoxia.
ABSTRACT
The present study was aimed to explore the changes of phosphorylated AMP-activated protein kinase (pAMPK) level in skeletal muscle after exposure to acute hypobaric hypoxia and exhaustive exercise. Thirty-two male Sprague-Dawley (SD) rats were randomly divided into sea level and high altitude groups. The rats in high altitude group were submitted to simulated 5 000 m of high altitude in a hypobaric chamber for 24 h, and sea level group was maintained at normal conditions. All the rats were subjected to exhaustive swimming exercise. The exhaustion time was recorded. Before and after the exercise, blood lactate and glycogen content in skeletal muscle were determined; AMPK and pAMPK levels in skeletal muscle were detected by Western blot. The results showed that the exhaustion time was significantly decreased after exposure to high altitude. At the moment of exhaustion, high altitude group had lower blood lactate concentration and higher surplus glycogen content in gastrocnemius compared with sea level group. Exhaustive exercise significantly increased the pAMPK/AMPK ratio in rat skeletal muscles from both sea level and high altitude groups. However, high altitude group showed lower pAMPK/AMPK ratio after exhaustion compared to sea level group. These results suggest that, after exposure to acute hypobaric hypoxia, the decrement in exercise capacity may not be due to running out of glycogen, accumulation of lactate or disturbance in energy status in skeletal muscle.