Migration and differentiation of intravenously transplanted bone marrow mesenchymal stem cells in rats with acute necrotizing pancreatitis

Objective To observe whether the intravenously transplanted homologous bone marrow mesenchymal stem cells (MSCs) can migrate to the impaired pancreas tissue in the rats with acute necrotizing pancreatitis (ANP). Methods MSCs were isolated from bone marrow of male Sprague-Dawley (SD) rats and adhered to the culture plate in vitro. Female rats were divided randomly into 3 groups:normal transplantation group, ANP transplantation group, ANP group with 10 rats in each group. ANP was induced by intraperitoneal injections with L-arginine. Both transplantation group received MSCs infusion through tail vein. 72 h later, the rats were sacrificed, the pancreas, heart, liver and kidney tissues were harvested, and the morphological changes were examined and scored, the characteristics of migration of MSCs to pancreas were detected with the expression of sry gene of Y chromosome by using chromogenic in situ hybridization (CISH). Results Rapid proliferation occurred in isolated MSCs after culture for 3 ～ 5 days and colonies were formed. After 3 generations, CD29 + CD44 + CD45-cells accounted for over 95% of all the cells. There ware massive tissue necrosis, inflammatory cells infiltration in the pancreas of ANP group, the pathological score was 10.31 ±0. 85, which were significantly higher than that in ANP transplantation group (7.30 ±0.79, P ＜ 0.05). Sry gene could be detected in the pancreas, heart, liver and kidney tissues. In addition, scattered distributed sry positive cells were observed in the normally transplanted pancreatic tissue, lots of sry positive cells were observed in the ANP transplanted pancreatic tissue, and they were located in the most injured areas.Conclusions The inflammatory pancreatic tissue has the ability of recruiting MSCs in vivo, which can alleviate local inflammation. Key words: Pancreatitis,acute necrotizing; Bone marrow mesenchymal stem cells; Cell movement; Cell differentiation; In situ hybridization