Scar formation, also known as tissue fibrosis, is a common response when most organs of the body get pathological damage.The cell populations involved are as follows: circulating fibroblasts from bone marrow, endothelial cells, resident fibroblasts, epithelial cells, and perivascular cells(pericytes).Pericytes are a kind of vascular wall cells, surrounding endothelial cells on the side of basement membrane in the microvascular system.It plays an important role in angiogenesis, maintaining the blood-brain barrier, regulating function of capillary blood, mediating the entry of immune cells into the brain, fibrosis response and so on.There is accumulating evidence suggests that pericytes are involved in the scar formation of central nervous system.This article reviews the scar formation process of central nervous system diseases such as spinal cord injury, epilepsy and traumatic brain injury, with emphasis on the role of pericytes in scar formation of central nervous system.On this basis, the perspective of pericytes involved in the regulation of scar formation is given.

Patients with central nervous system infection are always accompanied by severe long-term seque-lae and high mortality and disability, so timely diagnosis and treatment are required.Recognition of pathogens often plays a key role in treating such disease.This article reviewed new research progress in the differential diagnosis of different pathogens of central nervous system infection, which may provide the basis for the etiological and differential diagnosis of it.

Astrocytes exist in the central nervous system widely, through cell-cell communication in neurovascular units, playing an important role in providing metabolic support for neurons, regulating nerve function and plasticity and so on.There is evidence that exosomes play a key regulatory role in intercellular communication by carrying natural cargo molecules and participate in a variety of pathophysiological processes.However, the role of astrocyte-derived exosome in central nervous system diseases is largely unknown.In this paper, the classification, characteristics, biomarkers, physiological functions, functions of astrocyte-derived exosome and their roles in central nervous system diseases are reviewed, for a deeper understanding of the role of astrocytes in central nervous system diseases.

Objective:To explore the perivascular activation of reactive pericytes after status epilepticus(SE), and the relationship between pericytes and glial cells in proliferation and function.Methods:Eighty rats were randomly divided into control group( n=16) and model group( n=64, 16 for each group in SE1d, SE3d, SE7d, SE28d). The SE model was induced by intraperitoneal injection of lithium chloride and pilocarpine, and hematoxylin-eosin staining was performed on brain tissue sections to observe basic pathological changes.Use immunohistochemistry and Western blot to detect(neuron-glial antigen 2, NG2) expression, and use immunofluorescence technology to double stain NG2 and(glial fibrillary acidic protein, GFAP) to observe their relationship. Results:In the model group, the neurons were arranged disorderly, losing the ribbon structure, and the neurons appeared degeneration and necrosis.It was observed that the nuclei of the neurons were blurred, and the cytoplasm was agglomerated.There were more glial cells proliferation.Compared with the control group, it was found in model group that NG2 showed a dynamic high expression after SE( P<0.05). The number of pericytes increased significantly, reaching a peak at 7d, and the results of Western blot were consistent with the results of histochemistry( P<0.05). The aggregation of glial cells were induced in the surrounding area, and pericytes participated in the signal transduction of glial cells. Conclusion:Pericytes can induce the aggregation of glial cells and participate in the repairment in the form of glial scars after SE brain injury.