0bjective To study the expression of Fas in hippocampus of cerebral ischemia-reperfusion rats after treatment with monosialoganglioside (GM1). Methods Seventy-two SD rats were randomly divided into sham group (n=8), GM1 treatment group (n=32) and ischemia-reperfusion (I/R) group (n=32). According to the different time points (6 h, 12 h, 24 h and 3 d) of I/R, there were four subgroups in GM1 and I/R groups respectively. The expression of Fas in hippocampus was examined by immunochemistry and Western blot methods in all groups. Results Results of immunochemistry method showed that there was a little expression of Fas (the mean optical density was 0.17±0.02) in hippocampus of sham group, and the positive expression of Fas at different time points were increased significantly after reperfusion. The mean values of opti-cal density at different time points were 0.42±0.11, 0.51±0.13, 0.55±0.13 and 0.62±0.15 in I/R group, which reached to the peak at 3 d . The positive expression of Fas at different time points were significantly decreased in GM1 group (0.29 ± 0.09, 0.34±0.11, 0.37±0.12 and 0.43±0.12) than that of I/R group (P＜0.05). Conclusion Monosialoganglioside participated in the pathogenesis of cerebral ischemia-reperfusion injury by down-regulating the expression of Fas.

Objective : To investigate the effect and mechanism of Src homology 2 domain - containing protein tyrosine phosphatase inhibitor PHPS1 on atherosclerotic plaque vulnerability in ApoE knockout mice , and to provide a new idea for the study of atherosclerosis. Methods : Sixteen 8 ⁃week⁃old ApoE - / - mice were randomly divided into control group and PHPS1 group. The aortic root was fixed with formalin and sectioned. The collagen and macrophage contents in the plaque were evaluated by Movat and Sirius red staining. The activity of ERK and the expression of MMP⁃9 in the descending aorta were detected by Western blot. Results : The plaque area (0. 52 ± 0. 05) , (0. 31 ± 0. 03 ) , collagen content (0. 062 ± 0. 013 ) , (0. 136 ± 0. 022) and macrophage cell ratio (0. 799 ± 0. 031) , (0. 621 ± 0. 043) were different between PHPS1 group and control group ( P < 0. 01) . The results of western blot showed that PHPS1 inhibited the activity of ERK and decreased the protein expression of MMP⁃9 (P <0. 01) . Conclusion PHPS 1 , an inhibitor of SHP⁃2 , can inhibit ERK activity and decrease the expression of MMP⁃9 , thus reducing the degradation of collagen in fibrous cap and stabilizing vulnerable atherosclerotic plaque.