RESUMO
Objective: To investigate the physicochemical properties of sodium carboxymethyl starch(CMS) and its effect on erythrocyte rheology and oxygen carrying function. Methods According to the requirements of Chinese Pharmacopoeia,the physicochemical properties were determined for CMS120,CMS380 and hydroxyethyl starch 130 (HES130),including pH value,osmotic pressure molar concentration and viscosity. Normal saline,CMS120,CMS380 and HES130 were mixed with whole blood(7:3,V/V),respectively,and the experimental groups were set as whole blood group,whole blood+normal saline(NSB)group,whole blood+CMS120(CMS120B)group,whole blood+CMS380 (CMS380B)group,and whole blood+HES130(HES130B)group. The colloid osmotic pressure,blood viscosity,eryth- rocyte deformation and aggregation,and the partial pressure of oxygen when blood oxygen saturation was 50%(P50)val- ue were measured for each of these groups. Results: The osmotic pressure molar concentration and the viscosity of CMS120 and CMS380 were both significantly higher than those of HES130(all P<0.05)as indicated by the determina- tion of physicochemical properties. Compared with the whole blood group,the colloid osmotic pressure was significantly increased in the CMS380B and CMS120B groups(P<0.05),which was also significantly higher than that in the HES130B group(P<0.05). At low shear rate(10/s),compared with the whole blood group,the whole blood and the plasma vis- cosities were significantly increased in the NSB,CMS380B and CMS120B groups(all P<0.05),but the whole blood viscosity was significantly decreased in the HES130B group(P<0.05). Under the conditions of shear rate 10/s,50/s and 150/s,compared with the HBS130B group,the whole blood and the plasma viscosities were both significantly in- creased in the CMS120B and CMS380 groups(all P<0.05). At the effect of high shear rate,both the CMS380 and HES130 groups showed a tendency to promote erythrocyte deformation,and the CMS120B and CMS380B groups promot- ed erythrocyte aggregation,while the HES130B group inhibited erythrocyte aggregation amplitude(P<0.05). The P50 value was significantly higher in the CMS380B group than in the HES130B group(P<0.05). Conclusion: CMS130 and CMS380 could improve the rheological properties of erythrocytes and CMS380 could also promote the oxygen release of erythrocytes.
RESUMO
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.