| Background Alzheimer disease is one of the chronic neurodegeneration diseases, whose typical clinical pathology changes are the senile plaques caused by Amyloid-peptide (Aβ) deposition, neurofibrillary tangles (NFTs) within neurons, granulovacuolar degeneration of the pyramidal neurons in hippocampus, and the decrease of neurons in cortex and hippocampus. Amyloid-peptide seems to have a central role in the neuropathology of Alzheimer disease. Neurotoxicity of Aβ, especially Aβ1-42 induced apoptosis of neurons in AD pathogenesis has been the research focus. Now as well acknowledged that Aβinduced oxidative stress is significant for the development of AD, research has shown that Aβmay activate the NMDA receptor and promote the formation of oxygen free radicals which can induce neuronal damage. Mitochondria are extremely sensitive to oxidative stress injury, sustained oxidative damage can bring rapid destruction to mitochondrial membrane's structure and function, which can lead to more serious obstacles to energy supply, and the damage of mitochondrial endometrial will directly result in the reduction of mitochondrial membrane potential and mitochondrial membrane permeability pore (membrane permeability transitionpore, MPTP) over open, leading to cytochrome C and other apoptosis-inducing factor release into the cytoplasm, which become a key factor in initiating cell apoptosis. As the important role of mitochondria in mechanisms of Aβneurotoxicity, oxidative stress injury and neuronal apoptosis, in recent years, it is considered mitochondria an effective target in the treatment of neurodegenerative diseases such as AD. Butylphthalide (L-3-n-butyphthalide, NBP) was extracted from celery seed, is the first proprietary drug within the cardiovascular and cerebrovascular diseases field in China, as the anti-ischemic drugs,its mechanism of action has been deepley investigated, researches show that butylphthalide can improve mitochondrial membrane fluidity, increase ATP activity in neurons'mitochondrial and the stability of mitochondrial membrane and activity of mitochondrial Complex IV. It is reasoned that the drug will be helpful in the treatment with neurodegeneration diseases associated with mitochondrial damge and mitochondrial metabolic disorders. There are experimental use of butylphthalide to treat neurodegenerative diseases clinically, such as Alzheimer disease, Parkinson disease, Amyotrophic Lateral Sclerosis(ALS) and so on, however, the mitochondrial protective effect of butylphthalide in antagonist for Aβ1-42 induced apoptosis in primary cortical neurons culture, is unclear, yet the specific mechanisms are systematically explained.Objective To investigate Aβ1-42 induced apoptosis effect upon cortical neurons, use L-3-n-butyphthalide preteat the cortical neurons at the same time, and evaluate the effect of L-3-n-butyphthalide against Aβ1-42 induced apoptosis in primary cortical neuron cultures through a mitochondrial apoptotic pathway.Methods Primary rat cortical neurons were cultured and evaluated by immunofluorescence. After pretreatment with NBP of differernt concentrations (0. lumol/L, lumol/L, 10umol/L) 4h before exposure to Aβ1-42 (10 umol/L) for 24 h, changes of cell vialbilty were determined by MTT, the LDH,MDA,SOD enzymes activities was spectrophotometrically determined to address the oxidatieve status.cell morphology was observed by an inverted fluorescence microscope, and the apoptotic rate was determined, expressions of target proteins(total p38 MAPK, phospho-p38 MAPK, bcl-2, bax, cytochrome C,caspasce-3 and Cleaved Caspase-3) were determined by Western blot.Results1, Being exposed to Aβ1-42 for 24 h, cell vialbilty remarkably decreased, cell apoptotic rate incresaed(p<0.05),the MDA content and LDH activity increased, the SOD activity decreased(p<0.05), expressions of Bcl-2 and mitochondrial cytochrome C decreased(p<0.05) and expressions of Bax, cytoplasma cytochrome C, caspasce-3 and Cleaved Caspase-3 increased(p<0.05), expressions of phospho-p38 MAPK(pp38 MAPK) increased(p<0.05), but the expression of total p38 MAPK didn't show significant difference.2, Pretreatment with NBP for 4h can significantly inhibits the Aβ1-42 induced the cell vialbilty decrease(p<0.05),cell apoptotic rate increase(p<0.05), the MDA content and LDH activity increase, the SOD activity decrease(p<0.05).3, Pretreatment with NBP for 4h can significantly inhabits the Aβ1-42 induced the decreased expression of Bcl-2 and mitochondrial cytochrome C (p<0.05) and increased expressions of phospho-p38 MAPK, Bax, cytoplasma cytochrome C, caspasce-3 and Cleaved Caspase-3 are also signifcantly inverted(p<0.05).Conclusions NBP can inhibit Aβ1-42 induced AD neurons apoptosis, decrease the oxidative damage and the phosphorylation of p38 MAPK of cortical neurons induced by Aβ1-42,then inverts the associated mitochondrial apoptotic proteins'experession, which indicates NBP could protect AD neurons through a mitochondrial apoptotic pathway. |
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