| All trans-retinoic acid induces HL-60 to differentiate into granulocytes,neutrophils which have important immunological properties,especially in the inflammatory response.Initial adhesion of neutral granulocytes was mediateted by selectin,while stable adhesion is mediated by intergrin.The stable adhesion cells then migrate to the inflammatory part to play their immune response.For a long time,leukemia has caused the extensive attention of the researchers.At present,the treatment of leukemia is roughly divided into four categories,gene therapy and bone marrow transplantation,chemical treatment and differentiation treatment.Induction differentiation therapy aims to differentiate abnormal cells into normal cells.All-trans retinoic acid?ATRA?is the first induction drug that has been successfully used in the treatment of leukemia and induces acute promyelocytic differentiation toward mature granulocytes.HL-60is a cellular model for the study of acute promyelocytic leukemia,and the reason is that the induction of differentiation of HL-60 cells by ATRA is similar to the primary APL,and all-trans retinoic acid clinical trials of acute promyelocytic leukemia?APL?are experimental results of HL-60 cells in vitro.In this paper,we studied the proliferation and differentiation of HL-60 cells treated with ATRA and the rolling adhesion of HL-60 cells by E-selectin under fluid shear stress.All trans-retinoic acid induced differentiation of HL-60 cells into mature granulocytes.This paper elaborates from two aspects of biological cell morphology and cell biomechanical point of view.From the perspective of cell morphology function,we explored the initial concentration of cells and the optimal concentration of drug treatment.In this paper,we selected 1×10-5M,1×10-6M,1×10-7M three concentration to obtain cell growth curve.The rate of differentiation under different concentrations of 1×10-5M,1×10-6M,1×10-7M and different drug treatment time was determined by nitrotetrazol blue reduction test in order to obtain the optimal drug-induced concentration.The morphological changes of the cells under the concentration of1 x 10-6M ATRA were observed by the Swiss Giemsa staining experiment.It was found that with the extension of drug treatment,the cell appeared polymorphic nucleus,and the surface area of cells decreased.From the point of view of cell biomechanics,E-selectin-mediated rolling adhesion of HL-60 cells showed fluid-enhanced phenomenon under the fluid shear stress.With the increase of shear stress,the cell rolling velocity decreased first and then increased,and there is the characteristics of the catch band and slip band.At the shear stress of 0.4 dyn/cm2 or less,cell rolling velocity decreases with the increase of shear stress from 0.2 dyn/cm2 to 0.4dyn/cm2,at the shear stress of 0.4 dyn/cm2 or more,and the cell rolling velocity increased with the increase of shear stress from 0.4 dyn/cm2 to 0.6dyn/cm2.Under the same shear stress,with the extension of dosing time,the rolling velocity of HL-60 cells showed a decreasing trend.The rolling velocity of HL-60 cells showed dependence on drug treatment time and fluid shear stress.Furthermore,We found that the trend of frational stop time of the cells was opposite to that of the average velocity of the cells.Therefore,the regulation of the exposure time of ATRA and shear stress on the HL-60 cell rolling velocity was achieved mainly by regulating frational stop time of cells. |
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