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Objective: To compare the protective effect of nerve growth factor (NGF) and edaravone (a free radical scavenger) pretreatment against cerebral ischemia/reperfusion (I/R) injury to nerve cells., Methods: Cortical neurons of Sprague-Dawley (SD) mouse aged shorter than 24 hours were cultured for 7 days, then they were randomly divided into control group, I/R group, NGF of 10, 50, 100 microg/L pretreatment groups and 100 mumol/L edaravone pretreatment group. In pretreatment groups the cells were pretreated with drugs correspondingly. After culturing for 24 hours, glutamate of 200 mumol/L was given into the culture of all groups, except control group, for half an hour. Then culture medium in all groups were renewed with ordinary culture medium, and cultures were continued for 24 hours. The survival rate (by methyl thiazolyl tetrazolium assay), the content of lactate dehydrogenase (LDH, by spectrometry) and the rate of apoptosis (by flow cytometric) were determined. The cellular shape and ultrastructure were observed by hematoxylin-eosin (HE) staining and electronic microscopy correspondingly., Results: The survival rate of nerve cells in NGF groups and edaravone group was significantly higher than that in I/R group [(0.21 + or - 0.04)%, (0.23 + or - 0.04)%, (0.21 + or - 0.04)%, (0.24 + or - 0.04)% vs. (0.19 + or - 0.04)%]. The content of LDH in culture medium and the rate of apoptosis in NGF groups and edaravone group were lower than those in I/R group (P<0.05 or P<0.01). The release rate of LDH in each group was (0.50 + or - 0.06)%, (0.46 + or - 0.07)%, (0.50 + or - 0.02)%, (0.43 + or - 0.06)% vs. (0.56 + or - 0.03)%, respectively. The rate of apoptosis in each group was (10.77 + or - 1.07)%, (10.38 + or - 0.70)%, (13.34 + or - 0.57)%, (9.99 + or - 0.77)% vs. (14.52 + or - 0.77)%, respectively. The cellular shape and ultrastructure of nerve cells in NGF groups and edaravone group were affected much less than that of I/R group. NGF of 50 microg/L pretreatment group gave the best effect among three groups. There was no significant difference between NGF 50 microg/L pretreatment group and edaravone pretreatment group., Conclusion: NGF and edaravone pretreatment 24 hours before cerebral I/R give protective effects against cerebral I/R injury. The protective effects are best in NGF of 50 microg/L pretreatment group and edaravone pretreatment group, and there is no significant difference between them.

Objective: To study the protective effects of lidocaine and nerve growth factor (NGF) pretreatment on cerebral ischemia/reperfusion (I/R) injury., Methods: Fifty-four Mongolian gerbils were randomly divided into nine groups: normal group (Group A), lidocaine control group (Group L), NGF control group (Group N), lidocaine pretreatment groups at the point of 12, 24, 48 hours (named respectively Group L12, L24, L48), NGF pretreatment groups with NGF given 12, 24, 48 hours before injury (named respectively Group N12, N24, N48), with 6 animals in each group. Except Group A, the carotid artery on both sides were occluded for 20 minutes, then they were released to allow reperfusion. Alteration of apoptosis was observed with terminal-deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and the expression of Bcl-2 and Bax was assessed by immunohistochemistry method., Results: No apoptosis, Bcl-2 and Bax were found in Group A. In lidocaine or NGF pretreatment group, the expression of Bcl-2 (Group L12: 36.60 + or - 3.31, Group L24: 34.73 + or - 1.82, Group L48: 65.17 + or - 1.53; Group N12: 35.70 + or - 1.18 , Group N24: 37.30 + or - 3.86, Group N48: 62.77 + or - 2.91) was obviously increased comparing with control group (Group L: 24.53 + or - 1.48, Group N: 25.43 + or - 1.85), but the number of the apoptosis (Group L12: 32.87 + or - 0.99, Group L24: 31.90 + or - 4.14, Group L48: 24.50 + or - 0.70; Group N12: 32.80 + or - 1.27, Group N24: 32.83 + or - 1.30, Group N48: 23.30 + or - 0.86) and Bax expression (Group L12: 33.47 + or - 1.21, Group L24: 33.70 + or - 1.20, Group L48: 24.67 + or - 2.09; Group N12: 32.17 + or - 2.21, Group N24: 31.97 + or - 1.79, Group N48: 23.27 + or - 1.20) were significantly decreased comparing with the control group (the number of the apoptosis: Group L 67.43 + or - 3.92, Group N 67.80 + or - 3.82; Bax: Group L 59.73 + or - 1.32, Group N 59.37 + or - 1.54, P<0.05 or P<0.01). In lidocaine and NGF pretreatment groups, the number of cell apoptosis and expression Bax were significantly lower at 48 hours than those at 12 hours or 24 hours, but the cell expression Bcl-2 was obviously higher (all P<0.05). However, there was no difference between lidocaine and NEG pretreatment groups at each time point in regard of the number of cell apoptosis, expression of Bcl-2 and Bax., Conclusion: Lidocaine and NGF pretreatment before cerebral I/R can alleviate I/R injury to the cerebral tissue. The protective effect was most obvious when the treatment was given 48 hours before ischemia. The mechanism may be related with an increase in expression of Bcl-2 as well as a decrease in Bax level.

Objective: To observe the protective effect of verapamil pretreatment against cerebral ischemia-reperfusion injury in gerbils., Methods: Thirty-three Mongolian gerbils were randomized into the control group (group A, n=6, with sham operation), ischemia group (group B), and 3 verapamil groups (groups C, D, and E, n=7) with intraperitpneal verapamil injection (2 mg/kg) 48, 24 and 12 h before ischemia, respectively. In group A, the bilateral common carotid arteries were only exposed without clamping, and in the other 4 groups, the arteries were clamped for 20 min followed by reperfusion for 50 min. The gerbils were then decapitated and the forebrain cerebral cortex was removed to determine superoxide dismutase (SOD) and glutathione (GSH) activities and measure the contents of malondial dehyde (MDA), endothelin (ET) and calcitonin gene-related peptide (CGRP). The left forebrain cerebral cortex was sampled in each group to observe the ultrastructural changes under electron microscope., Results: In groups C and D, SOD activities were significantly higher than those in group B (P<0.05), and in group E, the SOD activity elevation was not statistically significant (P>0.05). In groups C, D and E, GSH activity was significantly higher than that in group B (P<0.05). MDA content was significantly lower in groups C and D than in group B (P<0.05), but comparable between groups E and B (P>0.05). ET content was also significantly lower in the pretreatment groups (P<0.05), but CGRP content higher (not statistically so, however) than those in group B. The more serious ultrastructural damage of the cerebral tissue was observed in group B, but only mild damage was found in the verapamil groups., Conclusions: Verapamil given 12-48 h before cerebral ischemia may protect the gerbils from cerebral ischemia-reperfusion injury by enhancing SOD, GSH activities and decreasing ET content.

Objective: To study the effect of nerve growth factor (NGF) pretreatment on apoptosis of neurons and the expression of Bcl-2 and Bax protein in cerebral cortex and hippocampus CA1 zone following global cerebral ischemia/reperfusion (I/R) injury in gerbils and to explore the mechanism of protection and the best time window of NGF pretreatment., Methods: Global cerebral I/R injury model was induced by occlusion of bilateral carotid arteries. NGF was injected into the lateral ventricle. Thirty gerbils were randomly divided into five groups, with six animals in each: sham operation group (A group), I/R injury group (B group), NGF pretreatment 12, 24 and 48 hours groups (C, D and E group). Gerbils in all groups were sacrificed after being subjected to 20 minutes of cerebral ischemia followed by 72 hours reperfusion, except A group. Neural apoptosis was identified by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), and immunohistochemistry was used to detect the expression of Bcl-2 and Bax protein in cerebral cortex and hippocampus CA1 zone., Results: Compared with B group, the number of apoptotic neurons and the expression of Bax positive cells in NGF pretreatment groups were decreased significantly (all P<0.05), while the expression of Bcl-2 positive cells was increased significantly (all P<0.05). The apoptotic rate in cerebral cortex and hippocampus CA1 zone and expression rate of Bax protein positive cells were the lowest, but the expression rate of Bcl-2 protein positive cells was the highest at 48 hours., Conclusion: NGF pretreatment can significantly decrease the neuronal apoptosis of the cerebral I/R injury in gerbils, and the best time window of NGF pretreatment is 48 hours. The mechanism of protection may be related to induction of Bcl-2 protein expression and inhibition of Bax protein expression by NGF pretreatment, thereby preventing neuronal apoptosis.