Abstract: Objective To investigate the therapeutic effect and mechanism of micheliolide (MCL) on peritoneal effusion in model mice with ascites tumor. Methods H22 ascites mouse model was established by i.p. injecting H22 cells (0.2 mL, about 2×107 cells) in 40 BALB/C mice. Mice were randomly divided into MCL group (n=20, 50 mg/kg MCL once a day for 7 days) and model group (n=20, 0.1 mL/d normal saline once a day for 7 days). The daily data of bodyweights, abdominal circumference and behavior of the mice were observed and recorded. Thirteen mice were sacrificed at 24 hours after the last administration, and tumor markers (CA199, CEA, serum ferritin, CA242, AFP) were detected by ELISA. HE staining was performed to observe the pathological changes of liver and ascites. The flow cytometry was used to detect the apoptosis of ascitic tumor cells in two groups. Results The bodyweights and abdominal circumference were decreased significantly in MCL group than those in model group from the day four of experiment (P < 0.05). Compared with the model group, the levels of CEA, CA242 and AFP were decreased in MCL group, while the serum ferritin was increased. At the same time, the degree of diffuse edema of hepatocytes in the lobules and ascitic tumor cells was decreased in MCL group than that in model group, but the apoptotic rate of ascitic tumor cells was elevated obviously in MCL group（P < 0.05） . Conclusion MCL has a significant inhibitory effect on H22 ascites tumor bearing mice, and the mechanism is mainly through the induction of apoptosis of liver cancer cells.

Key words: liver neoplasms, ascites, apoptosis, tumor markers, biological, mice, inbred BALB C, Micheliolide, H22 hepatocarcinoma, ascitic tumor