Abstract: Objective To explore the effect of low dose hydroquinone(HQ)pretreahnent on the cell viability and the expression of NQ01,HSP10 and 2-Cys Prxs in umbilical cord blood mononuclear cells (UCBMC).Methods Mononuclear cell from cord blood were isolated and Annexin V/PI staining assay was applied to evaluate the effect of low level HQ on human hematopoietic system cells Real tine PCR was perfouned to deteunine the expression of NQ01,HSP10 and 2-Cys Prxs.Results The results ofAnnexin V/PI staining assay showed that the UCBMC weremore tolerable to 250μmol/L HQ after pretreated with 10μmol/L HQ at cell survival level (44.92±25.10 vs 39.37±20.98).The results of real-tine PCR showed that compared with the control group,the expression of HSP10,Prx3 and Prx4 significantly increased by 2.22± 1.03,3.44±1.07 and 2.97±0.79-folds,respectively,in high dose group.The Prxl was increased by 1.08±0.29-folds in adaptive group.The expression of NQO1 was increased by 3.44±1.07 and 3.57±1.31-folds,respectively,in high and adaptive group.The expression of Prx4 in high dose group was significantly increased by 2.41±0.31-folds compared with that of the control and with a significant difference from that of in adaptive group.Conclusion Prxl,Prx3,prx4,and Hsp10 may take part in the adaptive response of UCBMC induced by hydroquinone.