Objective: To observe the effect of Hui medicine Zhali Nusi Fang (ZLNS) combined bone marrow mesenchymal stem cells (BMSCs) transplantation on neurons and P-glycoprotein (P-gp) expression in rats after cerebral ischemia reperfusion injury (CIRI). Method: Two hundred and fifty SD rats were randomly divided into the sham-operated group

the model group

the ZLNS group

the BMSCs transplantation group and the ZLNS combined BMSCs transplantation group. The rats except the 10 rats in the sham-operated group were subdivided into day 1

3

7 and 14 groups of 15 each. Middle cerebral artery occlusion (MCAO) model was duplicated by inserting a nylon thread. BMSCs were cultured and amplified by a whole bone marrow adherence method. Drugs were given to the rats by intragastric administration (14.6 g·kg-1·d-1)

BMSCs suspension solution were transplanted into brain through carotid artery (2×106/200 μL). Rat brain was taken out at 1

3

7

14 days after transplantation. The neuronal density (ND) in hippocampal CA1 area and brain pathological damage (BPD) were observed and determined. The expression of P-gp was measured by using an immunohistochemical method. Result: Compared with the sham-operated group

ND decreased (P<0.01)

BPD increased (P<0.01

P<0.05)

and the P-gp expression increased significantly (P<0.01) in the model group. Compared with the model group

the ND increased at day 3

7 and 14 in the ZLNS

transplantation and combination groups (P<0.01

P<0.05)

the P-gp expression decreased significantly in the ZLNS

transplantation and combination groups (P<0.01)

the BPD decreased in all groups

and the results were obvious at day 7 and 14 (P<0.01

P<0.05). Compared with the transplantation group

the ND increased at day 1 in ZLNS group (P<0.01)

decreased at day 14 in ZLNS group

and increased in combination groups (P<0.01)

the BPD alleviated at day 7

14 in the combination group (P<0.05)

the P-gp expression decreased at day 1

3 and 7 in the ZLNS groups

and the results were obvious at day 1 (P<0.05) and increased at day 14 (P<0.05)

the P-gp expression decreased significantly in all combination groups (P<0.01). Compared with the ZLNS group

all the indicators in the combination groups were improved (P<0.01

P<0.05). Compared with the same time group

all changes were more obvious at day 7 and were improved at day 14. Conclusion: The ND in hippocampal CA1 area and BPD had a variable degree of damage in rats after cerebral ischemia. Both ZLNS and BMSCs transplantation could improve the amounts and condition of neurons

and the effect was superior when they were combined. Its mechanism may be related to the regulation of the dynamic expression of P-gp.