OBJECTIVETo study the inhibitory effect of Xiaotan Sanjie Recipe (XSR) on the microsatellite instability of orthotopic transplantation tumor in MKN-45 human gastric cancer nude mice.

METHODSThe 3rd passage subcutaneous transplantation tumor was taken as the origin of the model by using MKN-45 human gastric cancer cell lines. MKN-45 human gastric cancer nude mouse model was established using OB glue adhesive method. Then 30 nude mice were divided into the model group, the XSR group, and the chemotherapy group. Mice in the XSR group were intragastrically given XSR at the daily dose of 0.4 mL. Mice in the chemotherapy group were intragastrically given Fluorouracil at the daily dose of 0.4 mL. No intervention was given to mice in the model group. After 6 weeks of medication, the tumor weight was measured, and the tumor inhibition rate calculated. The size, the peak height, and the peak area of 5 microsatellite instability sites were detected.

RESULTSThe tumor inhibition rate was 40. 84% in the XSR group. The tumor weight was significantly lower in the XSR group than in the model group (P < 0.01), showing no statistical difference when compared with the chemotherapy group (P >0.05). The incidence of high microsatellite instability (MSI-H) in the model group was 70%, and the incidence of low microsatellite instability (MSI-L) was 30%. Microsatellite stable site tended be stable after 6 weeks of XSR treatment.

CONCLUSIONXSR showed inhibition on microsatellite instable orthotopic transplantation tumor in MKN-45 human gastric cancer nude mice.