Salvianolic acid A protects rats against cerebral ischemic injury by regulation Wnt/glycogen synthase-kinase-3β/β-catenin signaling pathw ay / 国际脑血管病杂志

ABSTRACT

Objective To investigate the protective effect of salvianolic acid A (SAA) on permanent focal cerebral ischemia in rats and its possible mechanisms. Methods Fifty-four adult male Sprague-Daw ley rats w ere randomly divided into a sham operation group, a cerebral ischemia group, and a SAA group ( n =18 in each group). A model of permanent middle cerebral artery occlusion w as induced by the intraluminal suture method.At 0 h and 6 h after modeling, the rats of the SAA groups w ere intraperitonealy injected SAA (3 mg/kg). The other groups w ere injected equal volume of saline. At 24 h after modeling, the neurological deficit scores w ere performed. 2,3,5-Triphenyl tetrazolium chloride (TTC) staining w as used to detect cerebral infarction volume. TUNEL staining w as used to detect cel apoptosis. Both immunohistochemical staining and Western blotting w ere used to detect the expressions of Wnt3a, β-catenin, and phosphor-glycogen synthase-kinase-3β(p-GSK-3β) in the ischemic cortex. Results The neurological deficit scores show ed that no neurological deficits w ere observed in the sham operation group (score 0). The neurological deficit score in the SAA group (median and interquartile range) w as significantly low er than that in the cerebral ischemia group (3 [2-3] vs.4 [3-5]; Z = -2.679, P =0.007). No infarcts w ere observed in the sham operation group. The infarct volume in the SAA group w as reduced significantly compared w ith the cerebral ischemia group (79.038 ±10.665 mm 3 vs.212.702 ±8.029 mm 3; t = 24.525, P < 0.001). Very few positive cels w ere observed in the sham operation group. The numbers of TUNEL -positive cels in the SAA group and the cerebral ischemia group w ere 29.667 ±1.366/HP and 63.333 ±0.894/HP, respectively. The former w as significantly less than the latter ( t = 14.115, P < 0.001). Immunohistochemical staining show ed that the number of Wnt3a positive cels in the sham operation group, the cerebral ischemia group, and the SAA group w ere 35.500 ±2.572/HP, 18.056 ±3.765/HP, and 29.000 ±2.376/HP, respectively. There w ere significant differences among the 3 groups ( F = 115.972, P < 0.001), and those in the SAA group w ere significantly more than the cerebral ischemia group ( P < 0.01). The numbers of p-GSK-3βpositive cels in the sham operation group, the model group, and the SAA group w ere 7.944 ±2.127/HP, 37.444 ±3.434/HP, and 11.222 ±1.734/HP, respectively. There w ere significant differences among the three groups (F =730.580, P < 0.001), and those in the SAA group w ere significantly less than the cerebral ischemia group ( P < 0.01). The numbers of β-catenin positive cels in the sham operation group, the cerebral ischemia group, and the SAA group w ere 26.722 ±26.722/HP, 16.556 ±1.854/HP, and 21.333 ± 1.940/HP, respectively. There w ere also significant differences among the 3 groups ( F < 33.385, P <0.01), and those in the SAA group w ere significantly more than the cerebral ischemia group ( P < 0.01). Western blot analysis show ed that Wnt3a expression levels in the sham operated group, the cerebral ischemia group, and the SAA group w ere 1.000 ±0.190, 0.800 ±0.185, and 1.198 ±0.262, respectively. There w ere significant differences among 3 groups ( F = 9.621, P < 0.001), and those in the SAA group w ere significantly higher than the cerebral ischemia group ( P < 0.01). The p-GSK-3βexpression levels in the sham operation group, the cerebral ischemia group, and the SAA group w ere 0.650 ±0.150, 1.290 ± 0.250, and 1.190 ±0.250, respectively. There w ere also significant differences among the 3 groups ( F =19.668, P < 0.001), and those in the SAA group w ere significantly higher than the cerebral ischemia group (P <0.01). The β-catenin expression levels in the sham operation group, the cerebral ischemia group, and the SAA group w ere 1.200 ±0.210, 0.500 ±0.120, and 1.100 ±0.220, respectively. There w ere significant differences among the 3 groups ( F = 33.385, P < 0.001), and those in the SAA group w ere significantly higher than the cerebral ischemia group ( P < 0.01). Conclusions SAA has certain protective effect on permanent cerebral ischemia injury in rats. Its mechanism may be associated w ith the up -regulation of the expression of Wnt3a and β-catenin and the dow n-regulation of the expression of p-GSK-3β.