The Effect Of Antioxidants Derived From Plants On Ex Vivo Expansion Of CD34~+ Cells

Ex vivo expansion is apotential approach to overcome the limited amount of hematopoietic stem cells(HSCs)in cord blood transplantation.However,recent studies indicate that high levels of intracellular reactive oxygen species(ROS)that are frequently caused by glucose and cytokines weaken the cellular proliferation dramatically.Addition of antioxidants,such as flavonoids,polyphenols,and anthraquinones isolated from plants,would benefit ex vivo expansion were examined comprehensively.In the present study,freshly isolated CD34+ cells from umbilical cord blood were cultured in serum free medium with cytokine cocktails.First of all,the dose effect of flavonoids on ex vivo expansion of CD34+ cells wasstudied.The results showed that an increase of total cells and CD34+ cells was yielded by the addition of 0.1 ?M Puerarin;the expansion of total cells,CD34+ cells and CD34+ CD38-cells was promoted significantly by the addition of 1?M hyperoside.The fold expansion of total cells,CD34+ cells and CD34+ CD38" cells could achieve 54.9±9.6,8.94±1.87 and 8.0±0.9 folds respectivelyafter 14 days culture with 1?M hyperoside,which were significantly higher than those in control group.And the cells cultured with 1?M hyperoside showed same re-expansion ability of CD34+ cells as those of the cells cultured without hyperoside.Further,the effect of hyperoside on the level of intracellular ROS and the rate of apoptosis cells were investigated,the result showed that the proportion of apoptosis cells was markedly decreased by the addition of 1?M hyperoside,however,the level of cellular ROS was not affected during culture with hyperoside.Moreover,the dose effect of polyphenols and anthraquinone on ex vivo expansion of CD34+ cellswere studied.The results demonstrated that the fold expansion of total cells and CD34+ cells could achieve57.2±12.8and 9.7±0.8 folds respectively,after 14 days culture with 10?M catechin,which increased significantly compared with those in control group.And the cells cultured with 10?M catechin showed same re-expansion ability of CD34+ cells as those in control group.Furthermore,the effect of catechin on the level of intracellular ROS and the rate of apoptosis cells were investigated,the results showed that the proportion of apoptosis cells was markedly decreased by the addition of 10?M catechin,however,the level of cellular ROS was not affected during culture with catechin.After 14-day culture with 1?M aloe emodin,the fold expansion of CD34+ cells and CD34+ CD38-cells were 5.4±1.1 and 5.8±0.9 folds respectively,which were both much higher than those in control group,but the re-expansion ability of CD34+ cells was decreased obviously compared with control.The proportion of apoptosis cells was markedly decreased by the addition of 1?M aloe emodin,however,the level of cellular ROS was not affected during culture with aloe emodin.The results indicated that the addition of those antioxidants promoted ex vivo expansion of HSCs by reduced the percentage of apoptosis cells.The above results provided a theoretical basis for the application of antioxidants to optimize the ex vivo expansion of hematopoietic stem cells.