Differentiation of rat bone marrow stem cells in liver after partial hepatectomy

AIM： To investigate the differentiation of rat bone marrow stem cells in liver after partial hepatectomy. METHODS： Bone marrow cells were collected from the tibia of rat with partial hepatectomy, the medial and left hepatic lobes were excised. The bone marrow stem cells （Thy^＋CD3^-CD45RA^- cells） were enriched from the bone marrow cells by depleting red cells and fluorescence-activated cell sorting. The sorted bone marrow stem cells were labeled by PKH26-GL in vitro and autotransplanted by portal vein injection. After 2 wk, the transplanted bone marrow stem cells in liver were examined by the immunohistochemistry of albumin （hepatocyte-specific marker）. RESULTS： The bone marrow stem cells （Thy^＋CD3^-CD45RA^- cells） accounted for 2.8% of bone marrow cells without red cells. The labeling rate of 10 μM PKH26- GL on sorted bone marrow stem cells was about 95%. There were sporadic PKH26-GL-labeled cells among hepatocytes in liver tissue section, and some of the cells expressed albumin. CONCLUSION： Rat bone marrow stem cells can differentiate into hepatocytes in regenerative environment and may participate in liver regeneration after partial hepatectomy.

ALK5 transfection of bone marrow mesenchymal stem cells to repair osteoarthritis of knee joint

Previous studies have suggested that the transforming growth factor-β receptor ALK5 is crucial for articular chondrogenesis by bone marrow mesenchymal stem cells. Here, the wild-type ALK5 plasmids were mutated by overlapping extended PCR and transfected into bone marrow mesenchymal stem cells. The knee joint osteoarthritis mouse model was constructed by cutting oft＂ the anterior cruciate ligament and divided into three groups： saline group, bone marrow mesenchymal stem cells and ALK5-transfected bone marrow mesenchymal stem cells group. HE staining showed that the articular cartilage lesions were more serious of saline group compared with that of mesenchymal stem cell group, and this trend was more pronounced as time goes on. Immunohistochemical staining showed that although the expression level of type II collagen in all three groups down-regulated gradually upon time, its expression in ALK5-transfected bone marrow mesenchymal stem cells group was significantly enhanced compared with the other two groups. Micro-CT also suggested that ALK5 transfection of mouse bone marrow mesenchymal stem cells would promote repairing the knee cartilage lesions with arthritis of the mice. Although the osteoarthritis mechanism underlying a variety of factors work together, and the appropriate proportion of ALKS/ALK1 was also emphasized for the treatment of osteoarthritis. This work therefore demonstrated that ALK5 transfection of bone marrow mesenchymal stem cells could be a promising stem cell therapy for repair of cartilage lesions.