Kallikrein promotes endogenous neuronal stem cell proliferation, mioration, and selective differentiation after focal cortical infarction / 中华神经科杂志

ABSTRACT

Objective To investigate whether delayed treatment with exogenous kallikrein on neurogenesis after focal cortical infarction in stroke-prone renovascular hypertensive rats (RHRSP). Methods Seventy-two RHRSP were divided into 3 groups. Twenty-four rats were given human tissue kallikrein ( 1.6 × 10-2 PNAU/kg) and 24 rats were given vehicle through tail venous daily for 2 or 6 days consecutively starting at the 24th hour after distal middle cerebral artery occlusion (MCAO). 24 rats underwent sham-operation. Cell proliferation was examined by using 5'-bromo-2'-deoxyuridine (BrdU, 50 mg/kg). Rats were respectively sacrificed 3, 7, 14 or 28 days after MCAO. Results Treatment with kallikrein significantly increased the number of BrdU+ cells in the ipsilateral subventricular zone (SVZ) (304.0±73. 9 vs 167.0±32.2 vs 56.0±12.2 at 7 d after operation, q =7.165, 12.916 and 5.751 respectively,all P<0.05) and in the peri-infarction region (490.0±82.0 vs 308.0±51.5 vs 49.0± 9.5 at 7 d after operation, q = 7.920, 19.184 and 11.264 respectively, all P < 0.01 ), and increased the number of BrdU+/DCX+ cells (225.0±13.6 vs 98.0±9.6 vs 23.0±5.6 at 7 d after operation, q = 30.731,48.735 and 18.004 respectively,all P < 0.01) in the ipsilateral SVZ compared with the vehicle group or the sham-operated group, which began on the 3 day, peaked in 7--14 days after MCAO, and then gradually decreased. Compared with the vehicle group, exogenous kallikrein markedly increased the number of BrdU+/NeuN+ cells (21.0±3.4 vs 13.0±2.6 at 14 d, P =0.001 ) in the peri-infarction region after MCAO. The kallikrein group showed a better functional improvement than the vehicle group after stroke ( all P < 0.05). Conclusion Our study suggests that administration of exogenous kallikrein at 24 h after cortical infarction enhances the SVZ neuroblasts proliferation, migration, and selective differentiation and improves functional recovery after stroke.