OBJECTIVETo observe the effects of Guipi Pill (GPP) on bone marrow cell cycle of mice exposed to benzene and to explore its possible mechanisms for regulating hematopoiesis.

METHODSSeventy-two Kunming mice were randomly divided into 6 groups, i.e., the normal control group, the model group, the Western medicine treatment group, the large, middle, and small dose GPP groups, 12 in each group. The mice were exposed to manually simulated high concentrations of benzene fqr eight h every day, fourteen successive days, to replicate benzene intoxication model. Mice in the large, middle, and small dose GPP groups were administered with 8, 4, 2 mg/kg GPP per day respectively by gastrogavage. Mice in the Western medicine treatment group were administered with leucogen (at the daily dose of 1.5 mg/kg) and batyl alcohol (at the daily dose of 5 mg/kg) by gastrogavage. Mice in the model group and the normal control group were administered with normal saline by gastrogavage, once daily, for 3 successive weeks. The nucleated bone marrow cell count and the cell cycle of bone marrow cells were detected using flow cytometry.

RESULTSCompared with the normal control group, the nucleated bone marrow cell count obviously decreased in the model group (P <0.05). Compared with the model group, the nucleated bone marrow cell count obviously increased in the large and small dose GPP groups, and the Western medicine treatment group (P <0.01). Compared with the normal control group, the S phase cell ratio and proliferation index (PI) increased, and the G0/G1 phase cell ratio decreased in the model group, showing statistical difference (P <0.05). The G0/G1 phase cell ratio decreased, while the G2/M phase cell ratio and PI increased in the large dose GPP group. The S phase cell ratio decreased in the middle dose GPP group, showing statistical difference when compared with the model group (P <0.01, P <0.05). Compared with the Western medicine treatment group, the G2/M phase cell ratio and PI increased, and the G0/G1 phase cell ratio decreased in the large dose GPP group, showing statistical difference (P <0.01).

CONCLUSIONGPP could promote the recovery of hematopoietic functions of benzene exposed mice by ending off G1 or G2-phase arrest, accelerating G0/G1-S phase and S-G2/M phase transition, promoting the proliferation of bone marrow hematopoietic cells, and improving the peripheral hemogram.