Rho kinase inhibitor fasudil protect neurons in hippocampal CA1 region following cerebral ischenda reperfusion through inhibiting MLK3-JNK signal transduction pathway in rats

Abstract

Objective To investigate the effect of Rho kinase inhibitor fasudil on mixed lineage kinase 3 （MLK3）, c-Jun NH2-terminal kinase （JNK） phosphorylation, caspase-3 expression, and neuronal injury in hippocarnpal CA1 region follwong cerebral ischemic rep erfusion in rats. Methods A total of 72 Sprague-Dawley rats were randomly divided into sham operation, ischemia-reperfusion, normal saline, and fasudil groups. A global cerebral ischemic model was prepared by four-vessel ligation. The levels of MLK3 and JNK phosphorylation, and caspase-3 expression were detected by Western blot analysis. Cresyl violet staining was used to detect the numbers of survival neurons in hippocampal CA1 region. Results When 6 hours after ischemia-reperfusion, the level of MLK3 phosphorylation in the fasudil group （1.13 ± 0. 03） was sigaificantly lower than that in the normal saline group （2. 08 - 0. 01,P = 0. 000 3）, while the levels of MLK3 was no significant difference. When 3 hours after ischemia-reperfusion, the level of JNK phosphorylation in the fasudil group （1.27 - 0. 02） was significantly lower than that in the normal saline group （2. 09 - 0. 01, P = 0. 000 2）, while the levels of JNK was no signaificant difference. When 6 hours after ischemia-reperfusion, the expression level of caspase-3 in the fasudil group （1.28 ± 0. 02） was significantly lower than that in the normal saline group （2. 10±0. 01 ,P=0. 000 6）. When 5 days after ischemia-reperfusion, the pyramidal cells in hippocampal CA1 region almost completely disappeared in the ischemia-reperfusion group, and only a few cells left （9. 8 ± 2. 1）. The numbers of survival pyramidal cell （8. 28 ±3.2） in hippocampal CA1 region in the fasudil group was significantly more than that in the normal saline group （11.8 ± 1.6, P 〈 0. 05）. Conclusions Fasudil may significantly inhibit the ischemia-reperfusion-induced phosphorylation of MLK3 and JNK, as well as the expression of caspase-3, and thus reduce neuronal injury in hippocampal CA1 region. Key words: Brain ischemia; Fasudil; Neuroprotective agents; rho-associated kinases; MAP kinase kinase kinases; JNK mitogen-activated protein kinases; Caspase 3; Hippocampus; Rats