中樞神經(jīng)系統(tǒng)損傷后細(xì)胞增殖效應(yīng)的實(shí)驗(yàn)研究
[Abstract]:The glial scar formed after the Central Nervous Systerm (CNS) injury in adult animals is an important factor in the failure of CNS regeneration. In the past, the mature glial scar is the co structure of extracellular components (such as collagen type IV and laminin) and cell components (astrocytes, fibroblasts, macrophages) The reactive proliferation of astrocytes is the main cell component. Oligodendrocyte precursor cell (OPC) is a recent discovery of the fifth kinds of fine cell [1]. except neurons, astrocytes, oligodendrocytes, and microglia, but it is currently about whether OPC is involved in CNS against damage. The study of its significance and its significance is still less in the early 90s of the.20 century. It was proposed that adult mammalian CNS exist neural stem cells (Neural Stem Cell, NSC) [2], and a large number of studies have confirmed that NSC exists in a wide range of CNS, and these NSC are mostly in a state of rest in the body, stimulated by pathological conditions such as CNS injury or by external signal molecules. To be activated and proliferate, the lower layer of the ventricle (subventricular zone, SVZ) and the underlayer of the dentate gyrus of the lateral ventricle (subgranular zone, SGZ) are the.Parent in the two NSC enrichment regions of the adult mammalian CNS, which prove a variety of brain damage models, which can cause the proliferation of NSC in the dentate gyrus and subventricular zone of the damaged region. The proliferating cells can differentiate into [3] '[4]' [5] '[6]., such as astrocytes and neurons, so CNS damage can not only cause the activation of glial cells in damaged sites, but also lead to the proliferation of NSCs in damaged sites and distant sites. In recent years, more and more studies have shown that adult mammalian activity NSC is only microring existing in specific signal molecules. BMP4 and Noggin are [7]., a pair of protein molecules that play an important role in the proliferation and differentiation of NSC, which confirm that BMP4 and Noggin regulate the differentiation of neural stem cells in the subventricular region by BMP4 and Noggin, and the BMPs signal differentiates into astrocytes by promoting the NSC to the astrocytes in the subventricular region, and inhibits the production of [8]. Our study found that BMP4 also has the function of promoting the differentiation of NSC into astrocytes in the hippocampus of adult animals, [9]., however, whether BMP4 and Noggin have a similar role in other parts except the hippocampus and subventricular region. What is the effect of BMP4 and Noggin on the differentiation of proliferating cells after CNS damage? There is still to be further study Confirm.
In this study, unilateral exucleation of the rat was used as an animal model to observe the expression of GFAP and NG2 positive cells in the lateral superior colliculus at different time points after the injury. It was confirmed that the unilateral exucleation of the lateral colliculus after unilateral exucleation of the brain existed in the brain, and the GFAP positive astrocytes, and the significance of the proliferation of NG2 positive OPC, were found in the second part. BrdU markers were used to observe the proliferation of BrdU positive cells in the dentate gyrus and subventricular zone after unilateral exucleation of the eyeball, combined with BrdU/GFAP and BrdU/DCX immunofluorescence, to explore the differentiation direction of the proliferation positive cells. The last part was to further explore the factors affecting the differentiation of the proliferating cells after the injury of CNS. In situ hybridization and Western-blot were used to detect the expression of BMP4 mRNA and Noggin mRNA in the superior colliculus at different time points after injury and the expression of Noggin protein.
Main results:
1. after unilateral exucleation, the GFAP staining of the lateral superior colliculus increased in 24h than that in the normal control group. The expression of 24h to 1W increased after the operation, and the number of GFAP positive cells in the upper colliculus reached the peak at 1W, and the dyeing deepened and the prominences increased. But the GFAP staining did not increase step by step between 1W to 3W after the operation.
2. after unilateral enucleation, the NG2 staining of 24h superior colliculus increased. The number of 1W NG2 positive cells reached a peak after injury, and the number of NG2 positive cells decreased slowly from 1W to 3W.
3. using the BrdU labeling method, we found that a small amount of BrdU positive cells were found outside the vascular endothelial cells of the lateral colliculus after unilateral exucleation of the 24h, and the number of positive cells reached the peak at 1W, and the number of positive cells decreased at 2W after 2W, and the BrdU positive cells decreased further at 3W.
4. after unilateral exucleation, the number of BrdU positive cells in the dentate gyrus and subventricular zone of 24h was slightly higher than that in the control group. The number of BrdU positive cells reached the peak at 1W, and the number of BrdU positive cells decreased gradually between 2W and 3W. Besides, we observed that the number of positive cells in the lateral ventricle of the lateral ventricle increased after 2W. The number of BrdU positive cells in corpus callosum increased.
After 5. unilateral exucleation, the DCX positive cells in the dentate gyrus and subventricular zone of 1W were significantly increased, the number of positive cells in the subsequent two weeks decreased and the level of 3W decreased to the normal control group.
6. the double immunofluorescence double labeling showed that a small amount of BrdU/GFAP double standard positive cells were detected in the BrdU positive cells with the proliferation of the superior colliculus, and there was no BrdU/DCX double standard positive cells. The BrdU positive cells of the hippocampal dentate gyrus and subventricular zone had BrdU/GFAP positive double standard cells and BrdU/DCX double standard positive cells.
The 7.BMP4 mRNA in situ hybridization showed that the number of BMP4 mRNA positive cells in the lateral superior colliculus increased significantly after the unilateral exucleation of the 24h, and the staining was deepened. The expression of BMP4mRNA in the 1W group was lower than that of the 24h group. The number of BMP4mRNA positive cells in the 2W? 3W group was further reduced, and the 3W was reduced to the normal level.
8. the expression of Noggin mRNA in the lateral superior colliculus was not significantly different in each group. There was no significant change in 1W, 2W? 3W group compared with the normal control group. The results of Western-blot experiment also found that there was no significant difference in the expression of Noggin protein in each group.
The main conclusions are as follows:
1. we observed the reactive proliferation of GFAP positive astrocytes in the lateral superior colliculus after unilateral exucleation and the activation of NG2 positive OPC. It was confirmed that the unilateral exucleation of the lateral superior colliculus did have a damage response to the lateral superior colliculus, and established a new, simple and feasible animal model for the CNS damage; meanwhile, it was confirmed that the astrocytes were reactive proliferation except the astrocyte reactive hyperplasia, CN The response of S to injury also includes the activation of NG2 positive OPC.
2.CNS damage can not only induce local response to glial cells, including astrocytes and OPC, but also induce local BrdU positive cells. The number of BrdU positive cells in the dentate gyrus and subventricular zone in the hippocampus increases, and the BrdU positive cells proliferate in astrocytes and neuron progenitor cells.
The expression of BMP4 and Noggin after 3.CNS injury may be an important factor in regulating proliferation of differentiated cells after injury.
【學(xué)位授予單位】:第三軍醫(yī)大學(xué)
【學(xué)位級(jí)別】:碩士
【學(xué)位授予年份】:2007
【分類號(hào)】:R363
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