| Objective:To study the expression of MMP-9 and TIMP-1 after minocycline, ischemic post-conditioning against focal cerebral ischemia and reperfusion.to reveal the possible mechanisms of minocycline, ischemic post-conditioning in neuroprotection,to provide experimental evidence for the clinical treatment of cerebral vascular disease.Methods:The 250 male SD rats, weighing 250-320g, were randomly divided into sham operation group, ischemia reperfusion group, ischemic post-conditioning group, minocyciine group, combined treatment group. Each group was divided 6 time points (6h, 24h,48h,3d,5d,7d), Sham operation group had 10 rats, Other groups had 10 rats in each time point. We made the model of cerebral ischemia by MACO law Ischemic reperfusion group was bolt out of line to recover after 90 min of ischemia; Ischemic postconditioning group was pulled out cord 5 mm,30s and then plug the cord into the 30s after 90 min of ischemia, the normal blood perfusion was returned after three times; Minocycline group was given the injection of minocycline 45mg/kg after 90 min of ischemia, once every 12 hours; The combined therapy group was given the above two methods. The successful rat model were sacrificed at corresponding time points. We compare neurological score, infarct volume, brain water content, MMP-9 and TIMP-1 expression and the HE staining among groups.Results:1,Sham operation group did not haven neurological dysfunction at all time points. The neurological score of each group was the lowest at 48h,and significantly lower than the sham group (P<0.05); The neurological score of ischemic post-conditioning group and minocycline group were significantly better than the ischemia reperfusion group after 48h of reperfusion(P<0.05); The neurological score of combined treatment group were significantly better than ischemic post-conditioning group or minocycline group, there was significant difference(P<0.05); There was no significant difference between minocycline group and ischemic post-conditioning group.2,TTC staining showed that the sham group was not cerebral infarction;The infarction had occurred after ischemia reperfusion at each time point, which was most serious at 48h; The infarction volume of the each treatment group was significantly reduced, compared with ischemia reperfusion group (P<0.05); The infarction volume of combined treatment group was significantly reduced,compared with minocycline group or ischemic postconditioning group (P<0.05); There was no statistical difference between minocycline group and ischemic postconditioning group.3,Under light microscope HE staining was observed that sham group was no neuronal damage and inflammation, which had the normally cells; The staining of the ischemia reperfusion group was pale in ischemic area, There was the edema, micro-thrombosis, inflammation in the cortex of ischemic, and the number of neurons and glial cells was significantly reduced, cells were vacuolar degeneration, nuclear pyknosis was triangular, nucleoli disappeared. The neuronal damage of minocycline group and ischemic postconditioning group were lighter than the ischemia reperfusion group, The combined treatment group significantly reduced neuronal damage.4,The brain water content of sham operation group are basically same at each time points, there is no cerebral edema; The brain water content of ischemia reperfusion group gradually increased after reperfusion, which reached the peak after 48h of reperfusion, then gradually decreased, there was significant difference compared with sham group (P<0.05); The brain water content of ischemic postconditioning group and minocycline group significantly decreased, compared with ischemia reperfusion group after 24h of reperfusion (P<0.05); The brain water content of combined treatment group was significantly lower than ischemic postconditioning group or minocycline group at 24h,48h,3d,5d of reperfusion (P<0.05); There was no significant differences between ischemic postconditioning group and minocycline group.4,Sham operation group had less expression of MMP-9; The ischemia reperfusion group had the expression of MMP-9 at 6h, then further increase; The positive cells reached the peak at 48h of reperfusion; The expression of MMP-9 began to decrease after 3d of reperfusion and was weak at 7d of reperfusion (P<0.05); The expression of MMP-9 positive cells of combined treatment group were lower than ischemic postconditioning group or minocycline group at 24h,48h,3d,5d of reperfusion (P<0.05). The inhibitory effect of minocycline group did well than ischemic postconditioning group at 3d of reperfusion (P<0.05).5,Sham operation group had less the expression of TIMP-1 positive cells; The ischemia reperfusion group had the expression of TIMP-1 at 6h,The positive cells reached the peak at 24h of reperfusion and then gradually reduced after 48h of reperfusion, the expression was weak at 7d of reperfusion; The TIMP-1 positive cells of ischemic postconditioning group and minocycline group were lower than ischemia reperfusion group at 6h,24h,48h,3d of reperfusion (P<0.05);The combined treatment group was significantly lower than ischemic postconditioning group or minocycline group at 6h,24h of reperfusion (P<0.05); The expression of TIMP-lof minocycline group was lower than ischemic postconditioning group at 24h of reperfusion (P<0.05).Conclusion:1,Suture method is the ideal method to make the mode of focal cerebral ischemia in rat.2,MMP-9 and TIMP-1 is closely in a state of dynamic equilibrium in cerebral ischemia reperfusion injury. Minocycline and ischemic postconditioning could inhibit the expression of MMP-9/TIMP-1, Combined effect is more obvious.3,Minocycline and post-processing can reduce ischemic brain edema formation, reduced infarct volume and improve neurological dysfunction, combination has a more pronounced effect.
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