AIM:To evaluate the protective effects of transplantedand mobilized bone marrow stem cells(BMSCs)on micewith severe acute pancreatitis(SAP)and to probe intotheir possible mechanisms.METHODS:A mouse model of SAP induced by intraperitonealinjections of L-arginine was employed in the present study.Two hundred female Balb/c mice weighing 18-22 g wererandomly assigned into 4 groups.Group A was the stemcell mobilized group treated by injection of granulocyte-colony stimulating factor(G-CSF)into mice for 4 days at adose of 40 μg·kg~(-1)·d~(-1)before induction of SAP.Group B wasthe group of BMSCs transplantation,in which the micewere given the isolated BMSCs via the tail vein 4 daysprior to induction of SAP.Group C served as the modelcontrol and only SAP was induced.The mice withoutinduction of SAP in group D acted as the normal control.Atthe time of animal sacrifice at 24,48 and 72 h after inductionof SAP,blood samples were obtained and prepared todetect serum amylase,while the abdominal viscera wereexamined both grossly and microscopically for theobservation of pathological changes.RESULTS:The mortality of mice in the model control,groupsA and B was 34 %,8 % and 10 % respectively within 72 hafter induction of SAP.The serum level of amylase in themodel control was significantly increased at all time pointsafter induction of SAP as compared with that of the normalcontrol(P<0.05-0.01).When the mice were pretreatedwith BMSCs’ transplantation or G-CSF injection,their serumlevel of amylase was significantly reduced at 48 h and 72 hafter induction of SAP in comparison with that of the modelcontrol(P<0.05-0.01).In accordance with these observations,both gross and microscopic examinations revealed thatthe pathological changes of SAP in mice pretreated withBMSCs transplantation or G-CSF injection were considerablyattenuated as compared with those in the model control atall observed time points.CONCLUSION:Both transplanted allogenic and mobilizedautologous BMSCs can protect mouse pancreas from severedamage in the process of SAP. AIM: To evaluate the protective effects of transplanted and mobilized bone marrow stem cells (BMSCs) on mice with severe acute pancreatitis (SAP) and to probe intotheir possible mechanisms. METHODS: A mouse model of SAP induced by intraperitoneal injections of L-arginine was employed in the present study. Two hundred female Balb / c mice weighing 18-22 g were randomly assigned to 4 groups. Group A was the stem cell mobilized group treated by injection of granulocyte-colony stimulating factor (G-CSF) into mice for 4 days at adose of 40 μg · kg -1 · d -1 before induction of SAP. Group B wasthe group of BMSCs transplantation, in which the micewere given the isolated BMSCs via the tail vein 4 daysprior to induction of SAP.Group C served as the model control and only SAP was induced. The mice without induction of SAP in group D acted as the normal control. At a time of animal sacrifice at 24, 48 and 72 h after induction of SAP, blood samples were obtained and prepared to detect serum amylase, while the abdominal v iscera wereexamined both grossly and microscopically for the observation of pathological changes. RESULTS: The mortality of mice in the model control, groups A and B was 34%, 8% and 10% respectively within 72 hafter induction of SAP. The serum level of amylase in themodel control was significantly increased at all time points after induction of SAP as compared with that of the normal control (P <0.05-0.01) .When the mice were pretreatedwith BMSCs’ transplantation or G-CSF injection, their serum level of amylase was significantly reduced at 48 h and 72 hafter induction of SAP in comparison with that of the model control (P <0.05-0.01). In accordance with these observations, both gross and microscopic examinations revealed that the pathological changes of SAP in mice pretreated with BMSCs transplantation or G-CSF injection were irradiated attenuated as compared with those in the model control atall observed time points. CONCLUSION: Both transplanted allogenic and mobilizedautologous BMSCs can protect mouse ppancreas from severe damage in the process of SAP.