| ObjectiveTo investigate the protective effect of soybean isoflavone(ISO) in permanent focal cerebral ischemia induced by the left middle cerebral artery occlusion(MCAO) in rats.Methodes1.The MCAO model in rats: 20 Sprague Dawley rats were randomly assigned into two groups: Model and Sham OP. The permanent left middle artery occlusion was applied by thread technique in all rats in Model group. In 24h after the operation we observed the symptem and evaluated the function of nervous system. And we examined the pathology change of brain in two groups. 2.The protective effects of ISO on rats with cerebral ischemia: 60 Sprague Dawley rats were randomly assigned into six groups: ISO-L+MCAO(low dose soybean isoflavone+MCAO, 10mg/kg bwd);ISO-M + MCAO(moderate dose soybean isoflavone+MCAO, 20mg/kg bwd);ISO-H+ MCAO(high dose soybean isoflavone+MCAO, 50mg/kg bwd);VE+MCAO (VE+MCAO, 20mg/kg bwd);Sham OP (sham operated) and Model. ISO and VE were provided orally for 28 days. Then the permanent left middle artery occlusion was applied in all rats except for rats in Sham OP group. The function of learning and memory was examined in Y-maze. Ischemic penumbra was observed by MRI in lh and 6h after operation. The activity of SOD, GSH-Px and the content of MDA in brain and in serum before treatment and after operation wasmeasured by kit. The expression of HO-1 and HO-2 mRNA in brain and in blood lymphocyte before treatment and after operation was measured in RT-PCR. The concentration of homocysteine(Hcy) in blood before treatment and after operation was detected in HPLC. The morphological change of neuron were observed by the electronic microscope. And we examined the pathology change of brain in all groups. Results1. The MCAO model in rats: The rats in Sham OP group was all alive. There were two rats in Model group died in anesthesia and the operation in one rat inModel group was not be completed successfully. The rest 7 rats all had the symptem of Horner in left side, and the score of function of nervous system is in 1 to 3. In Model group we can find obvious pathology change. MCAO Model in this 7 rats reached the level of success..2. The protective effect of soybean isoflavone on cerebral ischemia in rats:(1) The protective effect of soybean isoflavone on cerebral ischemia in rats: Thefunction of learning and memory, the activities of SOD and GSH-PX in serum andbrain, the expression of HO-1 and H0-2mRNA in blood lymphocyte and brain,rADC, rDCavg, rFA in 6h in interesting areas in ISO-M+MCAO and ISO-H+MCAOwere significantly higher than those in Model^O.OS or PO.01). The content ofMDA in serum and brain, the concentration of Hey in plasma in ISO-M+MCAO andISO-H+MCAO were significantly lower than those in Model(P<0.01). The functionof learning, the activities of SOD and GSH-PX in serum and brain, the expression ofHO-1 mRNA in blood lymphocyte, H0-2mRNA in brain, rADC, rFA in 6h ininteresting areas in ISO-L+MCAO were significantly higher than those in Model(P<0.01). There were no significant difference in the content of MDA in bloodlymphocyte and brain, the activity of GSH-PX in serum, the expression ofHO-1 mRNA in brain, the expression of H0-2mRNA in blood lymphocyte, theconcentration of Hey in plasma, rDCavg in 6h in interesting areas betweenISO-L+MCAO and Model(/> > 0.05). (2)The comparison of the effect of ISO and VE:The activities of SOD and GSH-PX, the the expression of HO-1 and H0-2mRNA inblood lymphocyte and brain, rADC, rDCavg, rFA in lh and 6h in ISO-L+MCAO and ISO-M+MCAO were significantly lower than those in VE+MCAO. The content of MDA in serum and brain, the concentration of Hey in plasma were significantly higher than those in VE+MCAO (P<0.01). There were no significant difference in activity of SOD and GSH-PX, the content of MDA in serum and brain, the expression of HO-1 and HO-2 mRNA in blood lymphocyte and brain, the concentration of Hey in plasma, rADC, rDCavg, rFA in 6h in interesting areas between ISO-H+MCAO and VE+MCAO (P > 0.05). (3)The relationship between the dose of ISO and all indices: There were positive correlation between the dose of ISO and the function of learning and memory, the activities of SOD, GSH-PX in serum and brain, the expression of HO-1 and H0-2mRNA in blood lymphocyte and brain, rADC, rDCavg, rFA in 6h in interesting areas. There were negative correlation between the dose of ISO and the content of MDA in serum and brain, the concentration of Hey in plasma. (4)Pathology examination of brain: In Model group we could find obvious pathology change: the reduction of neuron, pyknosis of karyon, axon disapeared, a few neuron was in triangle, the glia cell was also in pyknosis condition, the clearance between neuron, glia cell, capillary vessel, minute vessel and brain interstitial substance was large, brain interstitial substance was loose. It was better in ISO-L+MCAO, ISO-M +MCAO, ISO-H+MCAO and VE+MCAO. (5)The observation of the morphological change of neuron in electronic microscope: In Model group the karyotheca was faint. The density of karyoplasms decreased. The rough surfaced endoplasmic reticulum was few. A large part of ribosome disappeared. Mitochondria was few and like granule, the configuration was faint. In ISO-H+MCAO group the configuration of neuron was in good condition. Karyon was big and in rotundity or ellipse shape. The two layer of karyotheca was clear. The rough surfaced endoplasmic reticulum was in short strip shape and the amount was large. The ribosome was abundance. The mitochondria was in pole, rotundity or ellipse shape.Conclusion1. The thread technique could be used in the establishment in MCAO model. The symptem in rats and the change of brain in pathology were obvious. The rats could reach the level of model success.2. ISO could enhance the function of learning and memory, the activities of SOD and GSH-PX in serum and brain, the expression of HO-1 and H0-2mRNA in blood lymphocyte and brain, rADC, rDCavg, rFA in 6h in interesting areas in MCAO rats. ISO could reduce the content of MDA in serum and brain, the concentration of Hey in plasma in MCAO rats. ISO could alleviate the change of pathology and ultrastructure in brain.3. ISO could protect the injury induced by cerebral ischemia through enhancing the activities of antioxidative system, the expression of HO-1 and HO-2mRNA and reducing the concentration of Hey in plasma. |
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