Limb remote ischemic postconditioning protects integrity of the blood-brain barrier after stroke.

Integrity of the blood-brain barrier structure is essential for maintaining the internal environment of the brain. Development of cerebral infarction and brain edema is strongly associated with blood-brain barrier leakage. Therefore, studies have suggested that protecting the blood-brain barrier may be an effective method for treating acute stroke. To examine this possibility, stroke model rats were established by middle cerebral artery occlusion and reperfusion. Remote ischemic postconditioning was immediately induced by three cycles of 10-minute ischemia/10-minute reperfusion of bilateral hind limbs at the beginning of middle cerebral artery occlusion reperfusion. Neurological function of rat models was evaluated using Zea Longa's method. Permeability of the blood-brain barrier was assessed by Evans blue leakage. Infarct volume and brain edema were evaluated using 2,3,5-triphenyltetrazolium chloride staining. Expression of matrix metalloproteinase-9 and claudin-5 mRNA was determined by real-time quantitative reverse transcription-polymerase chain reaction. Expression of matrix metalloproteinase-9 and claudin-5 protein was measured by western blot assay. The number of matrix metalloproteinase-9- and claudin-5-positive cells was analyzed using immunohistochemistry. Our results showed that remote ischemic postconditioning alleviated disruption of the blood-brain barrier, reduced infarct volume and edema, decreased expression of matrix metalloproteinase-9 mRNA and protein and the number of positive cells, increased expression of claudin-5 mRNA and protein and the number of positive cells, and remarkably improved neurological function. These findings confirm that by suppressing expression of matrix metalloproteinase-9 and claudin-5 induced by acute ischemia/reperfusion, remote ischemic postconditioning reduces blood-brain barrier injury, mitigates ischemic injury, and exerts protective effects on the brain.

[Effect of ligustrazine on cell proliferation in subventricular zone in rat brain with focal cerebral ischemia-reperfusion injury].

OBJECTIVE: To observe the effect of ligustrazine on cell proliferation in subventricular zone (SVZ) in rat brain with focal cerebral ischemia reperfusion injury. METHODS: Male SD rats were randomly divided into a normal group,a sham operation group,a ligustrazine treatment group, and a control group. The ligustrazine treatment group and the control group were further divided into 5 subgroups: 1d, 3d, 7d, 14d, and 21d reperfusion after 2h middle cerebral artery occlusion (MCAO). The focal cerebral ischemia-reperfusion model was made by MCAO. S phase cells were labelled with BrdU. Immunohistochemistry method was conducted to detect the BrdU positive cells. The total number of BrdU positive cells in the SVZ was measured. The expression of neuro nitric oxide synthase (nNOS) was detected with Western blot method. RESULTS: There was a significant increase of BrdU positive cells in SVZ of ligustrazine treatment in the 1d and 3d group compared with that of the control group (P<0.01). The total number of BrdU positive cells reached a peak in 7d group and declined afterwards. Cells proliferated also in SVZ on the contralateral side, and peaked at 7d. The nNOS expression of ligustrazine administration after the focal cerebral ischemia-reperfusion decreased at 1d and 3d after the reperfusion compared with that of the control group (P<0.05), and increased at 7d, but with no significant difference compared with that of the control group. CONCLUSION: Ligustrazine may promote the cell proliferation in SVZ of adult rats with ischemia-reperfusion injury by decreasing the nNOS expression.

[Effect of ligustrazine on nNOS expression and neuranagenesis in adult rats after cerebral ischemia-reperfusion injury].

OBJECTIVE: To observe the effect of ligustrazine on cell proliferation in the subventricular zone (SVZ) and dentate gyrus (DG) and nNOS expression in rat brain after cerebral ischemia-reperfusion injury. METHODS: Male SD rats were randomly divided into normal control group, sham operation group, model group and ligustrazine treatment group. The latter two groups were further divided into 5 subgroups for observation at 1, 3, 7, 14 and 21 days after reperfusion following a 2-hour middle cerebral artery occlusion (MCAO). The cells in S phase were labeled with BrdU, and immunohistochemistry was employed to detect BrdU- and nNOS-positive cells. The numbers of BrdU-positive cells in the SVZ and DG were measured. The expression of nNOS was detected by Western blotting. RESULTS: nNOS expression increased significantly in the model group as compared to the sham operation group (P<0.05), and ligustrazine treatment significantly lowered the expression level in comparison with the model group (P<0.05). Compared with the model group, a significant increase in BrdU-positive cells occurred in the SVZ of rats 1 and 3 days after igustrazine treatment (P<0.05), along with an increase of DG BrdU-positive cells. CONCLUSION: Ligustrazine significantly restrains ischemia-reperfusion injury-induced nNOS activity enhancement and promotes cell proliferation in the SVZ and DG of adult rats after ischemia-reperfusion injury.

[Effects of ligustrazine on hippocampal dentate gyrus cell proliferation after focal cerebral ischemia in adult rats].

OBJECTIVE: To explore the effects of ligustrazine on cell proliferation in hippocampal dentate gyrus subgranular zone (SGZ) after focal cerebral ischemia in adult rats. METHODS: Middle cerebral artery occlusion (MCAO) model was established in adult rats by placement of an intraluminal filament at the origin of the MCA. Ligustrazine was administered intraperitoneally at a daily dose of 80 mg/kg starting at 2 h after MCAO, and BrdU (50 mg/kg daily) was also injected intraperitoneally starting at 4 h after MCAO. BrdU-positive cells in the SGZ were counted 7, 14 and 24 days after MCAO, respectively. RESULTS: Compared with sham operation group, ischemic ipsilateral BrdU-positive cells in the ischemic model group increased 7 days after MCAO, reaching the peak on day 14, and decreased on day 21 (P<0.01). The number of ischemic ipsilateral BrdU-positive cells in ligustrazine group was significantly greater than that in the ischemic model group on days 7, 14 and 21 (P<0.01), and maintained the high level on day 21. CONCLUSION: Ligustrazine possesses long lasting effect of promoting cell proliferation in the SGZ after focal cerebral ischemia in adult rats.

[Effect of ligustrazine on cell proliferation in subventricular zone of lateral cerebral ventricle after adult rat suffering from focal cerebral ischemia].

OBJECTIVE: To explore the effect of ligustrazine on cell proliferation in subventricular zone of lateral cerebral ventricle after middle cerebral artery occluded (MACO) in adult rat. METHODS: SD male rats were randomly divided into three group: sham operation group, ischemic model group and Ligustrazine group. The model of the middle cerebral artery occlusion was established by placement of an intraluminal filament at the origin of left MCA. Ligustrazine was administered intraperitoneally with a dose of 80 mg/kg daily starting at 2 hours after MCAO. BrdU (50 mg/kg) was injected once a day intraperitoneally starting at 4 hours after operation. Number of BrdU-positive cells and expression of doublecortin (DCX) in subventricular zone (SVZ) were measured by immunohistochemistry on day 7, 14, 24 after operation. RESULTS: Compared with sham operation group, BrdU-positive cells in ischemic model group increased on day 7, reached the peak on day 14, then decreased on day 21 after operation. On day 7 and 14, the numbers of BrdU-positive cells in Ligustrazine group were markedly augmented and significantly more than those in ischemic model group (P < 0.01), but decreased on day 21. The expressions of DCX in SVZ in ischemic model group were enhanced on day 7 with lasting into day 14, and reduced on day 21, but still higher than those in sham operation group on day 7, 14, and 21, respectively. The expressions of DCX in SVZ in Ligustrazine group increased gradually along with prolong of ischemia and kept the high level up to day 21 after operation, and were higher than those in ischemic model group on day 14 and 21. CONCLUSION: Our results suggest that Ligustrazine may promote the cells of SVZ, which the adult rats suffer from the focal cerebral ischemia, to go into cell proliferation.

[The effect of ligustrazine on cells proliferation in cortex and striatum after focal cerebral ischemia in adult rats].

OBJECTIVE: To explore the effect of Ligustrazine on cells proliferation in cortex and striatum after focal cerebral ischemia in adult rats. METHODS: Focal cerebral ischemia was induced by left middle cerebral artery occlusion (MCAO) with suture method. Two hours later, injection of Ligustrazine (80 mg/kg, 1 time/d) was performed peritoneally. Four hours after the ischemia, 5-bromodeoxyuridine (BrdU) (50 mg/kg, 1 time/d) was injected peritoneally. At 7d, 14d and 21d after ischemia, BrdU-Labeled cells in the cortex and striatum were observed by immunohistochemical staining. RESULTS: In ischemia model group, at 7 day, BrdU-labeled cells were observed in the ipsilateral cortex and striatum. With the prolongation of ischemia, the number of BrdU-labeled cells increased, reached the peak at 21d. In Ligustrazine group, BrdU-labeded cells were observed with an intense distribution in ischemic penumbra of the cortex and striatum. With the prolongation of ischemia, the number of BrdU-labeled cells increased significantly at 14d, and reached the peak at 21d. The numbers of BrdU-labeled cells at 7d, 14d and 21d were more than those in ischemia model group respectively. CONCLUSION: Ligustrazine increase the proliferated cells in the cortex and striatum after focal cerebral ischemia in adult rats. The results suggest that it may be useful for promoting self-repair after ischemia.