Objective:To investigate the effect of Angelica polysaccharide on inhibition of proliferation and induced erythrocytic differentiation of human erythroleukemia cell line(K562).Methods:Techniques of cell culture were used in this experiment.The effect of APS on proliferation of K562 was examined by MTT、trypan blue staining and flow cytometry.The change of cell form was observed by Wright's stain.The effect of APS induced erythrocytic differentiation of K562 was detected by cytochemistry and spectrophotometric method.Results:APS can significantly inhibit the proliferation of K562 ex vivo,and the inhibitory extent is paralleled to the concentration and the acting time of APS;APS promoted the expression of Hb.Conclusion:APS can significantly inhibit the proliferation and induce the differentiation towards erythroid cell of K562 ex vivo.

The number of clinical postgraduates is growing with the reform of educational mode of postgraduates.It is a particular concern for medical colleges to improve educational quality of postgraduates,especially to cultivate postgraduates with great ability of observational study.The ability of clinical thinking and observational study is a key objective throughout postgraduate teaching.A good teaching method plays an important role in improving the ability of observational study for clinical postgraduates.A teaching platform combining academic theories with clincal pratice is a basis for promoting quality of clinical postgraduates.The construction of tutor team is a key point in elevating clinical observational ability.Academic exchange is a shortcut to cultivate postgraduates with great observational ability in clinical work.

Objective To explore the relative signal transduction pathway of angelica polysaccharide(APS) inducing K562 cells toward erythroid differentiation. Methods K562 cells were divided into control group and ASP group, the control group cells were routinely cultured and APS group cells were treated with APS(final concentration is 100-500mg/L). By using of benzidine staining and spectrophotometry, the characteristics of erythroid differentiation of K562 cell induced by APS were detected;By using of laser confocal microscopy, the distribution of JAK_2 and STAT_5 in K562 cells was observed;By using of Western blotting, the expression of JAK_2 and STAT_5 in nucleus and cytoplasm of K562 cells was detected, By using of imm～uno～pre～cipi～ta～tion, the phosphorylation change of JAK_2 in cytoplasm was tested. Results After being induced by APS, the benzidine staining positive rate of K562 was increased.With increasing the concentration of APS, hemoglobin synthesis in K562 cells was promoted accordingly. After being cultured for 12 hours, 24 hours and 48 hour, the expression of STAT_5 in nucleus of K562 cells induced by APS was significantly higher than that of control group, however, expression of STAT_5 in cytoplasm of K562 cell induced by APS was obviously lower. The expression of JAK_2 in K562 cells was not different between APS group and control group, but the JAK_2 phosphorylation level of APS group was much higher than that of control group.Conclusion APS can induce erythroid differentiation of K562 cells, and the mechanisms may be that APS can promote the phosphorylationthe of JAK_2, then stimulating nuclear translocation of STAT_5.

OBJECTIVETo investgate the signal transduction and regulation in erythropoiesis by angelica polysaccharides (APS) to clarify the mechanism for APS promoting hematopoiesis.

METHODThe mononuclear cells were isolated from foetus umbilic cord blood (mononuclear cells, MNCs), after MNCs were incubated in the presence of APS group (APS 200 mg x L(-1)) and control group for 24 h, the cells were stimulated with Epo (5 U x mL(-1)) for 0, 2, 5, 30 min, respectively. STAT5 was measured by ICC and laser confocal scanning microscope. JAK2, STAT5 in nucleus and cytoplasm were measured by western-blotting-ECL.

RESULTAngelica polysaccharide cooperated with Epo has significant impact on the expression of STAT5. The expression of STAT5 has significant difference between APS group and the control group at 4 time points. JAK2, STAT5 expressed in cytoplasm and nuclear of APS group significantly increased as compared to those of control group, and they expressed the strongest at 5 min.

CONCLUSIONJAK2, STAT5 signal transduction molecule plays an important role in the effect of APS cooperated with Epo on promoting hematopoiesis.

Angelica ; chemistry ; Blotting, Western ; Cells, Cultured ; Erythropoietin ; pharmacology ; Gene Expression ; drug effects ; Hematopoiesis ; drug effects ; Humans ; Janus Kinase 2 ; metabolism ; Microscopy, Confocal ; Polysaccharides ; pharmacology ; STAT5 Transcription Factor ; metabolism ; Signal Transduction ; drug effects