Abstract: Objective · To investigate the expression of LacZ gene mediated by intravenous injection of the single-stranded adeno-associated virus serotype 9 (ssAAV9) containing hypoxia-responsive element (HRE) promoter in the cerebral ischemic area, and further identify the types of brain cells that can be transfected by the vector. Methods · A mouse model of permanent left distal middle cerebral artery occlusion (dMCAO) was established. The expression of hypoxia-inducible factor-1 (HIF-1) in cerebral ischemic area was detected at 1 and 5 days after ischemia. The ssAAV vector containing HRE-regulated LacZ gene was packaged into the capsid of AAV9 virus (AAV9-H9LacZ), and AAV9-H9LacZ was injected into mice through jugular vein 1 h after the establishment of dMCAO model. Five days after injection of AAV9-H9LacZ, X-gal staining was used to detect the expression of β-galactosidase (β-gal) encoded by the LacZ gene in the ischemic area and liver tissue. Immunofluorescence double staining was used to detect the expression of β-gal in astrocyte, neurons and vascular endothelial cells. Results · The expression of HIF-1 was increased 1 and 5 days after ischemia. β-gal was mainly expressed in ischemic penumbra of mice injected with AAV9-H9LacZ. There was no positive expression of β-gal in the liver tissue of mice. β-gal was mainly co-expressed with glial fibrillary acidic protein as an astrocyte-specific marker, and a little of β-gal was co-expressed with neuron-specific nuclear protein. Conclusion · After cerebral ischemia, intravenous injection of AAV9-H9LacZ can effectively mediate gene expression in astrocyte in the cerebral ischemia area. HRE can effectively control the expression of the LacZ gene in cerebral ischemia.

Key words: adeno-associated virus serotype 9 (AAV9), cerebral ischemia, hypoxia-responsive element (HRE), astrocyte