| Object By observing the changes of MMP-9expression on rats with cerebral ischemia/reperfusion injury, to explore the protective effects of ATRA and the possible mechanism.Methods180healthy male Sprague-Dawley rats were divided randomly into sham operation group (Sham group)、ischemia-reperfusion injury group (OP group) and all trans retinoic treated group (ATRA group). Each group had60rats. Rats of OP group and ATRA group were subjected to ZeaLonga suture method. The rats in Sham group were subjected to the same surgical procedures as the other groups except that the middle cerebral arteries were not occluded. Rats of ATRA group were given gavage30ml/kg ATRA every24hours after operation. OP group and Sham group received saline. Each group according to the time of operation (1day,3day and7day) was divided randomly. Each group had20rats. Rats of every timeponts were used for TTC staining, EB staining, immunohistochemistry and Western Blot for detection of MMP-9, respectively.Results1. The score of motor functionIn Sham group there was no motor deficit, so the Bederson score of each rat was zero. Compared with OP group, the score of ATRA group was improved, especially3day group.(P<0.05).2. TTC stainingIn Sham group, there were no infarction areas found in the brains of rats. In OP group, the infarction volume reached a peak1day after reperfusion, and decreased from3day to7day. Compared with OP group, infarction volumes of ATRA group were smaller, especially1day group and7day group (P<0.05).3. The content of EBIn Sham group, the content of EB in brain tissue was very low. In OP group, the content reached a peak1day after reperfusion; then decreased gradually; on7day did not return to Sham group level. Compared with Sham group, the content of OP group was higher at different time (P<0.05). Compared with OP group, the content of EB of ATRA group was lower, especially1day and7day group.(P<0.05).4. The immunohistochemistryRats of Sham group almost did not express MMP-9. In OP group and ATRA group, MMP-9positive cells were located in surrounding infarction area and infarction area. MMP-9mostly expressed in cytoplasm of glial cells. Compared with Sham group, the expression of MMP-9of OP group was higher, especially3day and7day groups (P＜0.05). Compared with OP group, the expression of MMP-9of ATRA group was lower, especially3day and7day groups.(P<0.05).5Western Blot Expressions of MMP-9at each time point of OP group were significantly higher than that of Sham groups (P<0.05). There were significantly differences between ATRA groups and OP groups at each time points (P<0.05).ConclusionsATRA may reduce the permeability of blood brain barrier in rats with cerebral ischemia/reperfusion injury by down-regulating the expression of MMP-9. |
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