CD34+ bone marrow stem cells homing to embolized rabbit lung tissue / 第二军医大学学报

ABSTRACT

Objective To observe the homing of bone marrow stem cells (BMSCs) to the embolized lung tissues after mobilization and to investigate the potential mechanisms. Methods Thirty healthy Chinese big-ear rabbits were randomized into two groups regardless of gender pulmonary thromboembolism (PTE) group (model group), PTE+granulocyte colony-stimulating factor (G-CSF) mobilization group (experimental group), with each group having 15 animals. Stable PTE models were established by injecting autologous thrombus into the femoral veins of the animals (model group). The animals in the experimental group received daily hypodermic injection of G-CSF (10 μg/[kg��d]) for five days, which was started 4 days before the establishing PTE models and ended at one day after the models were established. The animals were sacrificed 24 hours after modeling in both groups for general sample observation. Hematoxylin-eosin (HE) staining was done for the samples. Immunohistochemical analysis was done to detect the expressions of CD34 and SDF-1 in the embolized area, edge area, and normal area. A medical image processing software was used to analyze the results of immunohistochemical results to calculate the relative contents of CD34 and SDF-1. Results (1)General sample observation the animals exhibited the damage of lung tissues in both groups, including splinter hemorrhage sites, local pale region and atelectasis. (2)Microscopic pathological observation the embolized areas of all animals exhibited interstitial edema and hyperemia, and many red blood cells entered the pulmonary alveoli. Increased monocyte infiltration was detected in the experimental group. (3)Results of immunohistochemical analyses and image analyses of CD34 Most CD34 expression was found in the embolized area, very weak expression was found in the edge area, and hardly any was detected in the normal area. CD34 expression in embolized area was significantly higher in the experimental group than that in the model group (P<0.01). More monocytes expressing CD34 were seen in the experimental group and only a small number of them were found in the model group. (4) Results of immunohistochemical analyses and image analyses of SDF-1 Most SDF-1 expression was found in the embolized area, and no expression was found in the edge area and normal area. SDF-1 expression in embolized area was significantly higher in experimental group than in the model group (P<0.01). Conclusion BMSCs expressing CD34 can home to the embolized lung tissues after PTE. The increased SDF-1 expression may be one of the mechanisms of BMSCs homing to embolized lung tissues after PTE. Mobilization with G-CSF can increase SDF-1 expression in embolized area, which can attract more BMSCs to home to embolized lung tissues.