| Objective: Intracerebral hemorrhage (ICH) is defined as the spontaneous bleeding of nontraumatic origin into the brain parenchyma. The basal ganglia are commonly affected structures (80%). In China, ICH is accounting for 40%–50% of all stroke hospital admissions, and its mortality is the highest. Neuron death of the center area of hemorrhage focus will induce neurologic impairment after ICH. However, there are few truly effective long-term treatments existing at present. To retrieve the agonal neurons around the hemorrhage area has been the objective of a variety of treatment strategies. Of all the strategies, cell therapy and gene therapy are regarded as the most promising ones. Bone marrow stromal cells(BMSCs,MSCs), a kind of bone marrow-derived stem cells, has been widely used to explore the development of cell and gene therapy for multiple diseases. MSCs possesses the following characteristics (i) easily available; (ii) capable of rapid expansion in culture; (iii) immunologically inert; (iv) capable of long-term survive and integration in the host brain; and (v) amenable to stable transfection and long-term expression of exogenous genes. In this study, we explored the survive and migration of MSCs in normal rat brain and area around the hemorrhage focus. This might be helpful to provide theory and experimental basis for repairation of ICH. Methods: MSCs was collected from adult Sprague-Dawley rats by density gradient centrifugation method. Then cell surface antigen CD11b, CD45 and CD90 were tested in order to estimate the purity of MSCs. After being expanded, transduction of MSCs with a retroviral vector containing the enhanced green fluorescent protein (EGFP) cDNA was performed. ICH animal model was obtained by injecting collagenase and heparin into the striatum. After praxiology test succeeded, 5μl MSCs suspension containing 5×104 cells was stereotactically transplanted into hemorrhage focus of ICH model and striatum of normal rats. Then rats were killed in batches at different time, and brain sections were prepared with a cryostat. Here, we examined the survive and migration of MSCs in the brain of normal rats and the area around hemorrhage focus using a fluorescence microscope, and examined EGFP expression of transplanted cells by immunohistochemical and immunofluorescence histochemical methods. Results: The observations showed that primary cultured MSCs had a multiple morphological appearance, and proliferated rapidly. Cell surface antigen test showed that CD90+/CD45-/CD11b- cells added up to 75%. MSCs expressed EGFP steadily in vitro, and survived for 8 weeks after being injected in the striatum of normal rats and area around hemorrhage focus of ICH model. Implanted cells migrated into multiple areas of the brain including the striatum, the corpus callosum, and the cortex ipsilaterally, as well as the corpus callosum and the cortex contralaterally. Many cells were found in blood vessels, vessel walls and area around the vessels. There was no evidence of grafts proliferation. In the hemorrhage focus, a few surviving MSCs had a multiple morphological appearance, migrated into the area around the hemorrhage focus,and most of them residented around the vessels. Conclusion: The results suggested that the cultured MSCs had a high purity, strong ability to proliferate, and great capability of long-term expression of EGFP. After the MSCs was transplanted into rat brain, there was no grafts proliferation. Besides, MSCs could survive for a long term in normal rat brain and area around the hemorrhage focus, and could migrate widely. There still need further study to confirm whether MSCs can effectively repair the damage caused by ICH.
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