The Studies On The Interaction Of Cesium Compounds With Erythrocytes Membranes And Its Trans-Membrane Behaviors

It is shown that the abnormal concentration of cesium is associated withmany diseases, such as cardiovascular disease, senile dementia, and tumours. That isbecause cesium can block the inwardly rectifying K⁺ channel and hyperpolarizationactivated current. Furthermore, there are numerous therapeutic potentials for cesiumtherapy, i.e. depression schizophrenia and cancer. Further study on the cesiumtransmembrane mechanisms are needed which can help understanding molecularinteractions and of great significance for designing relevant medicines.With the help of Graphite Furnace Atomic Absorption Spectrometry (GFAAS), theuptake of cesium (cesium 3,5-dinitrosalicylate, cesium 5-aminotetrazole, cesiumaspartate, cesium 5-sufosalicylate) by human erythrocyte and their transmembranemechanisms were systematically investigated in vitro. Firstly, we investigated thedynamics characterize of cesium compounds. In this foundation, Inhibition experimentswere carried out as follows: (1) 0.1 mmol·L^-1 nifedipine for Ca²⁺ channel. (2) 0.1mmol·L^-1 ouabain was used for Na⁺,K⁺-ATPase, (3) Replace NaCl with choline chloridein the PIB media and add 0.1 mmol·L^-1 ouabain in it to testify the possibility of Na⁺/Cs⁺countertransport, (4) 50μmol·L^-1 DIDS and 5 mmol·L^-1 NaHCO₃ for anion exchanger.Meanwhile, we investigated the effects of cesium compounds on erythrocyte membraneby Scanning Electron Microscopy(SEM), Raman and Atomic Force Microscopy(AFM).The results show that the uptake of cesium followed a first-order kinetic processduring the beginning 2 hours. The transport of cesium through Ca²⁺ channel isunavailable, but the degradation product of nifedipine can mediate the transfer of Cs⁺ asthe lipophilic ionophore. Most of extracellular cesium was transported into erythrocyteby Na⁺,K⁺-ATPase, however, other pathways for cesium were found: (1)Na⁺/Cs⁺-countertransport systems; (2) the anion channel.The results of SEM show that Cs(H₂Ssal) could change human erythrocytes' shape.There are blebs and protuberances appearing and developing gradually on the red cellsurface. Cs(H₂Ssal)change the erythrocytes from discoid shape to echinocytes andspheroechinocytes at higher concentration (1.8 mmol·L^-1). According to the bilayercouple hypothesis, these shape changes of erythrocytes are due to differential expansionof their two monolayers. The Raman results show that: (1) the polar parts of the phospholipid to becomemore stabilization, the fluidity of the erythrocytes membrane decreased; (2) the packingof the long chain of phospholipid and the -C=C- chain ofβ-carotene become losse in thelower cesium concentration and orderly in the higher concentration.The AFM image of the normal surface of intact erythrocytes membrane is featuredby closely packed globular particles (that is protein). The domain structures thatappeared after incubation with cesium are featured by the aggregation of the protein.