Establishment Of Curative Effect Index On Rat Acute Leukemia Treated With Cytosine Arabinoside

Objective:Cytosine arabinoside(Ara-C), a deoxycytidine analog , is used clinically for treatment of acute leukemia for many years and effective in the treatment. However,some patients still can't reach complete remission (CR) or relapse finally. The reason is relatively complicated.The individual differences of the Ara-C metabolizing enzymes activity and Ara-C multidrug resistance may be the most important factor.At present,there are not a index to directly reflect the curative effect on rat acute leukemia treated with Ara-C.So we establish a method to study the correlation between the index of curative effect and rat survival time for more investigation and guide the rationalization clinical administration of Ara-C.Methods:A reversed-phase liquid chromatographic (HPLC) method to determine Ara-C and uracil arabinoside (Ara-U) on a C18 column(4.6mm×250mm i.d.,5μm).The mobile phase was a mixture of 5% methanol and 95% 10 mmol·L^-1 phosphate buffer adjusted to pH 7.0 with NaOH.The flow-rate was 1.0mL·min^-1 and the detection wavelength was set at 280 nm.We used the SD rat to establish acute leukemia model by inoculating the WEHI-3 leukemic cells.The plasma samples were collected from the rats which were receiving Ara-C 1g/m² ivgtt. on the fifteenth day after 1×10⁶ WEHI-3 cells per rat inoculating. HPLC to determine the ratio of the plasma Ara-C and Ara-U(C_Ara-C/C_Ara-U)at 0min,5min,15min,30min.Result:Under these chromatographic conditions described above, The method was rapid,simple,The accurate,reproducible and the average recovery were >96% (RSD<4.0%). 5 to 25 days after inoculation,the number of peripheral blood WBC was remarkably increased .(P<0.001).This study describes a HPLC method to determine the concentrations of Ara-C and Ara-U in plasma, compare the correlation of C_Ara-C/C_Ara-U at a particular time point with the rats survive time.The coefficient: r=0.9076,P<0.001.Conclusion:The establishment of the HPLC chromatographic conditions described above was rapid,simple.The accurate,reproducible and the average recovery were suitably.The model of SD rat acute leukemia can be made by inoculating 1×10⁶ WEHI-3 cells,and this method have higher making model success rate,obvious symptom,longer survive time.Establish a index of the C_Ara-C/C_Ara-U be used to express the curative effect on rat acute leukemia treated with Ara-C.The determination of index may provide a scientific basis for clinical treatment.