Objective:To observe the distribution of grafted GDNF-modified neural stem cells in the rat brain with focal ischemia and to explore the neuroprotective effect.Methods:Neural stem cells(NSCs) of neonatal rat were cultured in vitro.The model of middle cerebral artery occlution(MCAO) and reperfusion was set up.Normal saline(NS)

NSCs and GDNF/NSCs were transplanted into the lateral ventricle of MCAO model after reperfusion 3 days by stereotaxis instrument

Neurological severity score(NSS) tests were undertaken in all groups 1

2

3

5

7weeks respectively before and after transplantation.Immunohistochcmistry was used to check the survival and distribution of NSCs in vivo.Results:NSCs tranfected after 2 d with recombinant adenovirus containing GDNF gene launched green fluoresent and expressed nestin.NSS of GDNF/NSCs groups and NSCs groups was significantly decreased than control groups at 1～7 w after reperfusion(P<0.05).NSS of the GDNF/NSCs group was lower than that of the NSCs groups in 2 w and 3 w subgroup(P<0.05).Grafted cells were located in the cortex and striatum of the lesion side.More reactive cells were found in the cortex and striatum at 3rd

5th and 7th week than at 2nd week(P<0.05).Compared with NSCs groups

the number of reactive cells in GDNF/NSCs groups were significantly increased at 2nd

3rd

5th and 7th week(P<0.05).In GDNF/NSCs groups

the neuropils were more dense and compact than in NSCs groups.Conclusion:GDNF transfected NSCs improved neural function and have a neuroprotective effect after being transplanted into brain of MCAO rats.