Objective To investigate the effect of astragalus polysaccharide (AP) on proliferation and apoptosis of human acute myelocytic leukemia cell line KG-1a and the underlying mechanisms.Methods Human acute myelocytic leukemia cell line KG-la was cultured under 37 ℃ and 5 ％ C02,when appropriate cell passage and cryopreservation were performed.After treatment for 48 h with different concentrations of AP,the proliferative activity and apoptosis rate of KG-1a cells were examined by CCK-8 assay and flow cytometry,respectively.The expressions of p-Akt and bcl-2 protein in AP-treated KG-1a cells were evaluated by Western blot.The expression of PTEN mRNA by quantified real-time PCR.Results The proliferative activity of KG-la cell was obviously suppressed by AP treatment,and the inhibition rate increased in a dosedependent manner.The flow cytometry showed that,compared with the control group,the apoptosis rates of KG-1a cells were significantly increased after treatment with AP for 48 h.The early apoptosis rates were (1.98±0.16) ％,(12.60±0.48) ％,(16.31±0.73) ％,the late apoptotic rates were (3.11±0.19) ％,(17.17±1.40) ％,(21.17 ± 0.81)％,the differences were statistically significant (P ＜ 0.05).Western blot showed that the expressions of p-Akt and bcl-2 protein in KG-1a cells decreased significantly after treatment with AP (P ＜ 0.05).In contrast,the mRNA level of PTEN increased (P ＜0.05),which was shown by real-time PCR.Conclusion AP could repress cellular proliferation activity of KG-1a cells,which could be attributed to inhibition of PTEN-PI3K-Akt signaling pathway.

OBJECTIVE: To investigate the interventional effect of the Chinese herbal preparation Xi Fu Pai Chen(XFPC) on pulmonary inflammation and fibrosis in rats with silicosis. METHODS: A total of 144 adult specific pathogen free male SD rats were randomly divided into 6 groups: blank control group, silicosis model group, drug administration control group and groups of low-dose,medium-dose and high-dose XFPC, with 24 rats in each group. Lung silicosis model was established by single inhalation tracheal instillation method, which was treated with 50.0 g/L silica suspension, in groups except in the blank control group. On the 7 th day of modeling, the rats in the drug administration control group were orally given tetrandrine(5 mg/kg body weight), while those in the low-, medium-and high-dose groups were given 43, 86 and 192 g/L of XFPC by atomization inhalation once a day for 20 minutes, 5 days a week for 4 weeks. At the end of drug administration, the histopathological changes of the lung were observed. The number and classification of cells in bronchoalveolar lavage fluid(BALF)were examined, and the levels of malondialdehyde(MDA) and interferon-gamma(IFN-γ) in BALF were measured by enzyme-linked immunosorbent assay. RESULTS: On the 7 th day after modeling, the body weight in the drug administration control group and XFPC high-dose group decreased compared with the blank control group(P<0.05). On the 35 th day after modeling, the body weights of rats in the other 5 groups were lower than that in the blank control group(P<0.05). The pathological changes of lung tissue(infiltration of inflammatory cells, fibrosis and size of silicon nodule) in drug administration control group and XFPC low-dose group were better than those in silicosis model group by naked eyes and under light microscope. The lung coefficient, the proportion of neutrophils and the level of MDA and IFN-γ in BALF of the drug administration control group and XFPC low-dose group decreased(P<0.05), and the proportion of macrophages in BALF increased(P<0.05) compared with the silicosis model group. There was no significant difference in lung coefficients and the relevant indices of BALF between XFPC medium-, high-dose groups and silicosis model group(P>0.05). CONCLUSION: Low dosage XFPC can improve pulmonary fibrosis and inflammation in rats with silicosis, and its mechanism of action may be related to reducing the levels of IFN-γ and MDA in BALF.