The Effects And Mechanisms Of C.nudiflora On Cognitive Impairment

Luohuazizhu,the dried leaves of Callicarpa nudiflora?C.nudiflora?,has been widely used for anti-inflammation and anti-bleeding in southern China.It was reported phenylethanoid glycosides?Ph Gs?,one of the main and effective components groups of C.nudiflora,showed the anti-inflammation,antioxidant activities and neuroprotective effects,some of them could be even detected in brain tissues and displayed effects of amelioration on cognitive impairment.From literature researches and our previous study,it was found that isoacteoside,one of the main components of C.nudiflora,was an important metabolite of many Ph Gs,which suggested that it might be the main active ingredient in vivo.However,the neuroprotective effects and mechanisms of isoacteoside reported rarely.Thus,this study will explore the effective substances of C.nudiflora on amelioration of cognitive impairment through the neuroprotective effects of isoacteoside relating to inflammatory reactions and oxidative stress.ObjectiveThe purpose of our study was to investigate the neuroprotective effects of C.nudiflora on cognitive impairment,the potential mechanisms relating to inflammatory reactions and oxidative stress and the effective substances of C.nudiflora.Methods1. Rats were injected with A?_1-42 into bilateral hippocampus to create the cognitive models,and then treated with different doses of extracts of C.nudiflora?CNEs??300,150,75 mg/kg?by oral administration once a day for 18 days.The learning and memory abilities of cognitive rats were detected by Morris water maze testing system after orally administered for16 days.The levels of reactive oxygen species?ROS?,superoxide dismutase?SOD?,malondialdehyde?MDA?,acetylcholinesterase?Ach E?,tumor necrosis factor-??TNF-??,interleukin-1??IL-1??and transforming growth factor-?1?TGF-?1?in serum or hippocampus of cognitive rats were detected by test kits.Morphology changes and ultrastructure's alterations in hippocampus were observed by microscopy and electron microscopy,respectively.The protein expressions of A?_1-42,advanced glycation end products?RAGE?,nuclear factor kappa Bp65?NF-?Bp65?,phosphorylated NF-?Bp65?p-NF-?Bp65?,inhibitor of?B-alpha?I?B??,phosphorylated I?B??p-I?B??,TNF-?,translocation of NF-?Bp65,gp91^phox,p47^phox?two subunits of nicotinamide adenine dinucleotide phosphate,NADPH?and inducible nitric oxide synthase?i NOS?were detected by Western blot.The m RNA expressions of A?_1-42,RAGE,NF-?Bp65,I?B?,TNF-?,gp91^phox,p47^phoxand i NOS were detected by real-time quantitative polymerase chain reaction?RT-q PCR?.The protein expressions of NF-?Bp65 and I?B?also detected by immunohistochemical method?IHC?.2.SAM mice were treated with different doses of isoacteoside?200,100,50 mg/kg?by oral administration once a day for 8 weeks.The biochemical molecules associated with oxidation and inflammation were detected by test kits.Morphology changes and ultrastructure's alterations were observed by microscopy and electron microscopy,respectively.The protein and m RNA expressions of A?_1-42,RAGE,factors related to NF-?B signaling pathway and NADPH oxidative stress pathway were analyzed by Western blot and RT-q PCR.The protein expressions of NF-?Bp65 and I?B?also detected by IHC.Results1.It was found that CNEs exhibited effects on learning and memory impairments amelioration,antiinflammation and antioxidation by decreasing escape latency,increasing the numbers of platform crossings and time spent in the target quadrant,down-regulating levels of ROS,MDA,Ach E and proinflammatory factors,as IL-1?and TNF-?,and up-regulating levels of SOD and TGF-?1 in serum or hippocampi in cognitive rats.CNEs showed neuroprotective effects by histopathological observations.2. CNEs reduced the protein and m RNA expressions of A?and RAGE,inhibited activation of NF-?B inflammation pathway to lower the generations of inflammatory mediators,by increasing expression of I?B?,reducing expressions of p-I?B?,NF-?Bp65 and p-NF-?Bp65,and inhibiting the translocation of NF-?Bp65,and inhibited activation of NADPH oxidative stress pathway to lower the generations of ROS and i NOS,by reducing expressions of gp91^phox,p47^phox and i NOS.CNEs ameliorated neuronal loss or damage in hippocampus might through antioxidation and antiinflammation.3. Isoacteoside,belonged to Ph Gs,showed amelioration of cognitive impairment,antioxidaition and antiinflammation activities on SAMP8 mice,which demonstrated the one of the bioactive components of C.nudiflora were Ph Gs.4. Isoacteoside reduced the protein and m RNA expressions of A?and RAGE,inhibited activation of NF-?B inflammation pathway and NADPH oxidative stress pathway.These results suggested the mechanisms of CNEs on neuronprotective effects was through alleviating oxidative stress and inflammation in brain and the effective substance were Ph Gs which represented by isoacteoside.ConclusionAll the results above demonstrated that C.nudiflora possessed neuroprotective effects on cognitive rats via anti-inflammation and anti-oxidation.Isoacteoside displayed amelioration of cognitive impairment,antioxidation and antiinflammation activities as well.One of the bioactive component groups of C.nudiflora on amelioration of cognitive impairment were Ph Gs which represented by isoacteoside in this study.