The Protective Effects Of LBP On Focal Ischemic Cerebral Injury In Mice By Attenuating The Mitochondrial Apoptosis Pathway

Object: To investigate the neuroprotective of Lycium barbarum polysaccharide (LBP) onfocal cerebral ischemic injury in mice and to explore its possible mechanism.Methods: Male ICR mice were used to make the model of middle cerebral arteryocclusion (MCAO) after intragastric administration with LBP (10,20and40mg/kg) andNimodipine (4mg/kg) for seven successive days. After24h of reperfusion, neurological scoreswere estimated and infarct volumes were measured by2,3,5-triphenyltetrazolium chloride(TTC) staining. Morphological changes in ischemic brains were performed forhematoxylin-eosin (HE) staining. The number of apoptotic neurons was detected by TUNELstaining. Activation of Caspase-3protein in ischemic brains was measured byspectrophotometry. The Bax, Bcl-2protein expression and CytC, Caspase-3,-9and cleavedPARP-1activation were investigated by immunofluorescence and western-blot analysis.Results: Compare to the vehicle group, LBP (20and40mg/kg) groups significantlyreduced infract volume and neurological deficit scores (P<0.05); compare to the vehicle group,LBP (10,20and40mg/kg) groups relieved neuronal morphological damage respectively andalso obviously attenuated the neuronal apoptosis (P<0.05). After24h of reperfusion, Compare tosham-operated group, the activation of Caspase-3was increased significantly in vehicle group(P<0.01), while LBP (40mg/kg) group and nimodipine (4mg/kg) group could markedlyreduced Caspase-3activity in ischemic brain (P<0.05). In the results of immunofluorescencetests, after24h of reperfusion, the expression of Bax, CytC and Caspase-3proteins weresignificantly increased in the vehicle group (P<0.01) and Bcl-2protein expression wasmarkedly lower than sham-operated group (P<0.01). The expression of Bax, CytC andCaspase-3proteins were obviously decreased (P<0.01) and Bcl-2expression was markedly increased (P<0.05) in LBP40mg/kg and nimodipine groups. In Western blot analysis results,expression of Bax, CytC, Caspase-3,-9and cleaved PARP-1proteins were significantlyincreased in vehicle group mice ischemic brains compared to sham-operated group after24hof reperfusion (P<0.01) and Bcl-2protein expression was obviously decreased (P<0.01). LBP40mg/kg and nimodipine groups could inhibit the overexpression of Bax, CytC, Caspase-3,-9and cleaved PARP-1proteins (P<0.05) and protect against the reduction of Bcl-2expression(P<0.05).Conclusion: Based on these findings we propose that LBP protects against focal cerebralischemic injury by attenuating the mitochondrial apoptosis pathway.