Protective Effects And Mechanism Of Zingiber Officinal(Ginger) On Experimental Cerebral Ischemia Reperfusion Injury

Objective1 To study the therapeutic effects of Zingiber officinale(ginger) on cerebralischemia using gernerally acknowledged models of cerebral ischemia.2 To sduty and compare the therapeutic effects of the three extracts ofginger(essential oil, ethanol extract and aqueous extract) on cerebral ischemia, todefine their effective doses basing on dose-effect relationship.3 To sduty the protective mechanism of the aqueous extract of ginger oncerebral ischemia and reperfusion by investigating ATPase, free radical, calciumoverloading, excitatory amino acid, apoptosis and relative gene expression viadifferent cerebral ischemia and reperfusion models in rats.4 To sduty the improving effects and mechanism of the aqueous extract ofginger on cerebral ischemia and reperfusion with cognitive impairment in ratsby investigating Morris spatial learning and memory, the function of cholinergicneuron in brain tissue and antioxidation.Methods1 Male SD rats were randomly divided into sham-operation group, modelcontral group, ligustrazine group and high, middle and low dosage groups ofginger. The model of focal cerebral ischemia in rats was established by the rightmiddle cerebral artery occlusion(MCAO). The neurological outcomes werescored. Step by step test was used to evaluate passive conditional reflex. Theinfarct size of brain was measured by TTC staining.2 Kunmin mice were randomly divided into 15 groups, includingsham-operation group, model contral group, nimodipine group and high, middleand low dosage groups for each extract of ginger (essential oil, ethanol extractand aqueous extract and their mixture). Cerebral ischemia and reperfusion(CIR)model in mice was made by bilateral corotid ligation and repeated cerebralischemia reperfusion. The changes of brain water content were measured by thewet and dry weight method. Spectrophotometric assay was used to measure theactivities of Na⁺,K⁺-ATPase, Ca²⁺-ATPase and superoxide dismutase (SOD)and the contents of malondialdehyde (MDA) in brain tissue. 3 Male SD rats were randomly divided into sham-operation group, modelcontral group, nimodipine group and high, middle and low dosage groups ofginger aqueous extract. Cerebral ischemia and reperfusion (CIR) model in ratwas established by Pulsinelli's "Four Vessel Occlusion" method. Activatedpartial thromboplastin time(APTT), prothrombin time(PT), thrombin time (TT)and fibrinogen(FIB) in blood were analysed. The changes of brain water contentwere measured by the wet and dry weight methods. The contents ofGlumatate(Glu), Asparate(Asp) and Glycine(Gly) in brain tissue were analysedby high performance liquid chromatography with fluorescent detection. Atomicspectrophotometry was used to measure contents of Ca²⁺, Na⁺, K⁺ in brain tissue.Spectrophotometric assay were used to measure the activity of Na⁺, K⁺ -ATPase,Ca²⁺-ATPase and SOD and the content of MDA in brain tissue.4 Male SD rats were randomly divided into sham-operation group, modelcontral group; nimodipine group and high, middle and low dosage groups of gingeraqueous extract. The model of focal cerebral ischemia-reperfusion (MCAO) in ratwas established by Zea Longa's thread method. Terminal deoxynucleotidylTransferase Biotin-dUTP Nick End Labeling(TUNEL staining) was used toobserve neuron apoptosis in cerebral cortex and hippocampus. The proteinexpression of caspase-3, Bcl-2 and Bax in cerebral cortex and hippocampus weredetected by immunohistochemistry method. HE staining was used to investigatepathological changes in cerebral cortex and hippocampus.5 Male SD rats were randomly divided into sham-operation group, modelcontral group, nimodipine group and high, middle and low dosage groups ofginger aqueous extract. The model of cerebral ischemia and reperfusion withcognitive impairment was established by bilateral corotid ligation and repeatedcerebral ischemia reperfusion. Spatial learning and memory abilities in bothplace navigation test and spatial prob test were evaluated with Morris watermaze. The activities of acetylcholinesterase (ACHE) in cortex and striatum tissue,SOD and MDA in brain tissue were detected by spectrophotometry.Results1 Efeects of ginger on focal cerebral ischemia in ratsCompared with the sham-operation group, the score of neurological symptomand the infarct size of brain increased, learning and memory abilities decreasedin model contral group rats. Ginger could lessen obviously the score ofneurological symptom and the infarct size of brain and raise learning andmemory abilities in MCAO rats, compared with model contral group. 2 Efeects of different extracts from ginger on cerebral ischemia andreperfusion in miceCompared with the sham-operation group, the activities of Na⁺,K⁺-ATPaseand Ca²⁺-ATPase declined significantly in CIR model contral group mice. Theactivities of SOD and the contents of MDA were not changed remarkably. Theessential oil, aqueous and ethanol extract of ginger could significantly increasethe activities of Na⁺,K⁺-ATPase, Ca²⁺-ATPase and SOD, decrease the contentsof MDA in brain tissue. The aqueous extract exhibited more dose-effectrelationship than other extracts.3 Efeects and mechanism of aqueous extract from ginger on cerebralischemia and reperfusion injury in ratsCompared with the sham-operation group, the contents of Glu, Ca²⁺, waterand MDA in brain tissue and FIB in blood increased, the activities of SOD,Ca²⁺-ATPase and content of Na⁺ in brain tissue and TT in blood declinedsignificantly in CIR model contral group rats. Aqueous extract Of ginger coulddecrease the contents of Glu, Ca²⁺ and water in brain tissue and FIB in blood,increase the activities of SOD, the ratio of SOD/MDA, the contents of Na⁺ andK⁺ in brain tissue and TT in blood, but no significant difference to Gly, ATPaseand MDA, compared with model control group.4 Efeects of aqueous extract from ginger on neuron apoptosis and relatedgene expression with focal cerebral ischemia and reperfusion injury in ratsCompared with sham-operation group, TUNEL positive cells and caspase-3,Bcl-2 and Bax immunoreative neurons in cortex and hippocampal tissueincreased significantly, the ratio of Bcl-2/Bax was decreased in MCAO modelcontrol group rats. Aqueous extract of ginger could decrease significantlyTUNEL positive cells and caspase-3, Bcl-2 and Bax immunoreative neurons incortex and hippocampal tissue and increased significantly the ratio of Bcl-2/Bax,compared with MCAO model control group.5 Efeects and mechanism of aqueous extract from ginger on cerebralischemia and reperfusion injury with conitive inpairment in ratsCompared with sham-operation group, the rats in model control groupexhibited serious learning and memory deficits in both place navigation test andspatial prob test, AChE activity decreased significantly in striatum tissue.Aqueous extract of ginger could not only improve the learning and memory abilities in both place navigation test and spatial prob test, but also increaseAChE activity and the ratio of SOD/MDA and decrease MDA content in braintissue.Conclusion1 Ginger and the it's essential oil, aqueous extract and ethanol extract hasobviously protective effects on cerebral ischemia and reperfusion in rats andmice.2 The therapeutic effects of aqueous extracts from ginger on cerebralischemia and reperfusion can be realized by ATPase protection, lowering EAAneurotoxicity, decreasing intracellular Ca²⁺ owerload, increasing antioxidantactivity and inhibiting apoptosis.3 The aqueous extracts from ginger has obvious effects on improvinglearning and momery abilities of cerebral ischemia and reperfusion rats withcognitive impairment. Antioxidant activity and increasing the function ofcholinergic neuron are likely to the partial mechanism.