| Objective:Stroke is one of the severest causes of deformity and death in human. A great deal of studies indicate that oxidative stress is the important causative factors of neuron trauma after cerebral ischemia-reperfusion injury. Lycopene is one of the antioxidants in diet. Accumulatiing evidences strongly suggest that lycopene has the protection effect of cerebrovascular diseases, human studies show that serum lycopene is negative related with cardio-cerebrovascular diseases. This study aimed to investigate the protection effects of lycopene on cerebral ischemia-reperfusion injury induced by focal cerebral ischemia in rats in oxidative stress and anoxic ways.Method:1. The establishment of Middle cerebral artery occlusion (MCAO)20 male SD rats weighting 260-280g were divided randomly to weight into A, B, C, D group, each group has 5 rats. The diameter of embolism thread each group were 0.22mm,0.24mm,0.26mm and 0.28mm. The model of cerebral ischemia-reperfusion injury was established by middle cerebral artery occlusion (MCAO). Finding the befitting diameter of embolism thread according to the successful rates of each group.2. The effects of lycopene on cerebral ischemia-reperfusion injury in rats inoxidative stress and anoxic damage.64 male SD rats weighting 130-140g were acclimatized for 3 days prior to bein-g divided randomly to weight into 5 groups:LPH(16), LPL(16), Model (16), SHAM (10) and Nor (6) group. Rats of LPH,LPL groups were given lycopene orally 20,5 mg/kg.bw per day, and Model, SHAM rats were given equal salad oil for 15d.Then cerebral ischemia-reperfusion injury was established by middle cerebral artery occlusi on (MCAO) in LPH,LPL and Model group, SHAM group was used as fake surgery control. The reperfusion was 2h after ischemia.24h after reperfusion, the neurological infarction sizes were measured and neurological deficits evaluated by a method of grading on a scale of 0-8 at 3,24h after reperfusion. The activities of SOD,CAT,NOS,iNOS,LDH, the contents of MDA,NO,ROS,LD in cortex of brain and serum uric acid were measured at 24h after reperfusion. The levels of Bcl-2 mRNA and HIF-1αmRNA in cortex and hippocampi were determined by using reverse transcri-ption polymerase chain reaction (RT-PCR) technique.Result:1. Successful rate of B group and death rate of D group are the highest; failure rates of A and C group are high.2. (1) The effect of LP on neurological infarction sizes, neurological deficits scores and brain index:Neurological deficits scores and infarction sizes of LPH, LPL group at 3,24h after reperfusion were lower than Model group(P<0.05), and the infarction sizes of LPH group were smaller than LPL group(P<0.05); The brain index of LPH, LPL and Model group were increased compared with SHAM and Nor group(P<0.05), but brain index of LPH were obvious lower than Model group(P<0.05).(2) The effect of LP on oxidative stress 24h after reperfusion:The content of MDA, ROS and serum UA of LPH and LPL rats (1.01±0.08 nmol/mgprot,114.23±18.91 Fluo unit/gprot,154.56±15.39 umol/L),(1.09±0.05 nmol/mgprot,135.89±14.17 Fluo unit/gprot,164.42±14.76 umol/L) were decreased compared with Model group(P< 0.05); CAT activity of LPH (1.20±0.11 U/mgprot), LPL (1.08±0.15 U/mg prot), and SOD activity of LPH(13.88±0.91 U/mgprot) were higher than Model group(P<0.05).(3) The effect of LP on inflammation and anoxia 24h after reperfusion:The NO value and NOS, iNOS activities of LPH, LPL,Model group rats (6.60±0.77μmol/gprot, 0.817±0.016 U/mg prot,0.502±0.022 U/mgprot), (7.13±0.47μmol/gprot,0.875±0. 095 U/mgprot,0.523±0.039 U/mgprot), (8.38±0.80μmol/gprot,1.030±0.101 U/mgprot,0.612±0.030 U/mgprot) were higher than SHAM and Nor group(P<0.05); but the NO, LD values and NOS, iNOS activities of LP rats were significantly decreased compared with Model group(P<0.05).(4) The effect of LP on the expression of HIF-1αmRNA,Bcl-2 mRNA in both cortex and hippocampi tissue:Compared with SHAM and Nor group, the expression of HIF-1αmRNA in both cortex and hippocampi tissue were increased in LPH, LPL and Model rats (P<0.05), but they were obviously higher in LP rats than in Model rats (P<0.05); the expression of Bcl-2mRNA in cortex of LPL rats and hippocampi of LPL and LPH rats were increased compared with Model group(P<0.05).Conclusion:1. The successful rate of MCAO with 0.24mm diameter is the highest for SD rats weighting 260-280g.2. Oral administration of lycopene can protect brain from cerebral ischemia-reperfusi on injury induced by focal cerebral ischemia and oxidative stress in rats. The possible mechanism may be related with increasing activities of antioxidant enzymes,producing and cumulating of ROS,inhibiting lipid peroxidation,alleviating inflammation and anoxia and upregulating the expression of HIF-1αmRNA as well as Bcl-2 mRNA. |
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