The Research On Lycium Barbarum Polysaccharides And Its Mechanism Involved In PI3K/Akt-GSK3? Pathway On Mice Brain After Focal Cerebral Ischemia

Object: Ischemic stroke is a major cause of mortality and disability in human meanwhile the second leading cause of death in developed countries.In this study we investigated whether a general extraction of Lycium bararum polysaccharides(LBPs)could protect the mice from focal cerebral ischemic injury.Additionally,we identified that the protective mechanism works through PI3K/Akt-GSK3? pathway.Methods: In the present study,LBP(10,20 and 40 mg/kg)and Nimodipine(6mg/kg)were utilized for seven successive days,then middle cerebral artery occlusion(MCAO)mice were used as in vivo cerebral ischemia models.1.To investigate the neuroprotective effect of LBP on focal cerebral ischemia in mice.(1)Regional cortical blood flow(r CBF)was measured using laser speckle contrast imaging,(2)Spontaneous EEG of cerebral ischemic in the cortex were recorded and the total powers were quantify,(3)Histopathological impairments were analyzed by Nissl and hematoxylin-eosinstaining in ischemic brain tissues,(4)motor coordination were estimated by rotarod,neurological deficit scores,locomotor activity test and tail immersion test.2.To explore the effects of LBP on focal cerebral ischemia in mice and the possible mechanism through PI3K/Akt-GSK3? pathway.(1)Tunel staining was utilized to detect the number of apoptotic neurons in brain tissue of cerebral ischemia injury in mice.(2)Western blot analysis was used to examine the expression of Akt?p-Akt?GSK3?(ser 9)?p-GSK3?(ser 9)?p-PDK-1?Mcl-1in brain tissues.(3)QPCR was used to quantify the m RNA level of PP2 A and GSK3? in ischemic brain tissues.Results: 1.Protective effects of LBP on focal cerebral ischemic mice.Compare to the vehicle group,(1)the cerebral blood flows of the LBP(20 and 40 mg/kg)and Nim group had a significant enhancement(p<0.05 and p< 0.01).(2)LBP(20 and 40 mg/kg)pretreatment significantly strengthen the total power compared with the vehicle group(20 mg/kg,p<0.05;40 mg/kg,p<0.01).(3)LBP(40 mg/kg)and Nim group ameliorated histopathological morphological lesion dramatically.(4)LBP(40 mg/kg)and Nim significantly reduced the neurological deficits scores(p<0.01),improved tailing latency times,locomotor activity and fall latency(p<0.01).2.Protective effects of LBP on focal cerebral ischemia in mice via PI3K/Akt-GSK3? pathway.Compared to vehicle group(1)LBP(40 mg/kg)and Nim group significantly decreased the number of apoptotic neurons in ischemic brain tissues(p<0.01).(2)the protein expression levels of p-Akt?p-GSK3?(ser 9)?p-PDK-1?Mcl-1 markedly increased(p<0.01)in LBP 40 mg/kg group.(3)the m RNA expression of PP2 A and GSK3? were significantly reduced(p<0.01)in LBP 40 mg/kg group.Conclusion: We demonstrate that LBP pretreatment can induce cell survival which resists cerebral ischemia injury via PI3K/Akt-GSK3? pathway activation.