| Research background: Spinal cord injury(SCI)is a damage of spinal cord that caused by trauma or diseases.As the main reason for paralysis or sensory deficits,SCI has aroused more and more attention in recent years.Until now,the therapeutic strategies to ameliorate neurologic injury in patients with SCI are very limited.Numerous studies have demonstrated that many factors,including ischemia mediated neurogenic shock,inflammation,ionic derangement,neurotransmitter accumulation,excitatory amino acid accumulation and cell apoptosis,are all involved in the pathogenesis of SCI.It is worthy believing that searching for novel and more effective therapeutic medicines for alleviating neurological injury will be helpful for SCI prevention and treatment.Angelica sinensis(Oliv.)Diels,a perennial herb,has been broadly used as herbal medicine in Asian countries.Angelica Polysaccharide(AP)is one of the most major active components isolated from the root of Angelica sinensis(Oliv.)Diels.Researches have proved that AP has a wide range of pharmacological activities,including immunomodulation,anti-tumor,anti-oxidation,anti-inflammation,anti-anaemia,hepato-protection and neuro-protection.However,there is no any information available about the effects of AP on SCI,yet.More experimental researches are still needed to explore the potential anti-inflammatory and anti-injury effects of AP on SCI.Micro RNAs(mi RNAs)are small and non-coding RNA transcripts ineukaryotic cells with 20–24 nucleotides(nt).As a class of key regulatory RNAs in eukaryotic cells,mi RNAs has been found to exertcritical roles in the regulation of multiple gene expression and cellular function.Increasing numbers of reports provide evidences that mi RNAs also participate in the pathogenesis of multiple human diseases,including SCI.The PC-12 cell line derived from a pheochromocytoma of the rat adrenal medulla.When treated with NGF(nerve growth factor),the PC-12 cells differentiate into neuron-like cells.This makes PC-12 cells useful as a model to study the function and pathophysiology of neurons.Research objectives:(1)Effects of AP on LPS-induced PC-12 cell viability loss and apoptosis.(2)Effects of AP on LPS-induced overproduction of inflammatory cytokines in PC-12 cells.(3)Effects of AP on the expression level of mi R-223 in LPS-treated PC-12 cells.(4)Correlation between mi R-223 and the protective effects of AP on LPS-treated PC-12 cells.(5)Mechanism of AP on protecting PC-12 cells from LPS-induced inflammatory injury.Research method: Rat pheochromocytoma PC-12 cells were purchased and cultured.PC-12 cells were exposure to LPS in this research.Cell viability was detected using cell counting kit-8(CCK-8)assay.Cell apoptosis was assessed using Guava Nexin assay.q RT-PCR was conducted to measure the expression of interleukin-1?(IL-1?),IL-6,tumor necrosis factor-?(TNF-?)and micro RNA-223(mi R-223).Cell transfection was performed to up-regulate the expression of mi R-223.Finally,protein expression levels of key factors involved in cell apoptosis,inflammatory reaction and nuclear factor kappa-B(NF-?B)pathway were evaluated using western blotting.Research result:(1)AP pre-treatment alleviated LPS-induced PC-12 cell viability loss and apoptosis.(2)AP pre-treatment repressed LPS-induced overproduction of inflammatory cytokines in PC-12 cells.(3)AP pre-treatment down-regulated the expression level of mi R-223 in LPS-treated PC-12 cells.(4)mi R-223 was involved in the protective effects of AP pre-treatment on LPS-treated PC-12 cells.(5)AP pre-treatment alleviated LPS-induced nuclear factor kappa-B(NF-?B)pathway activation in PC-12 cells by down-regulating mi R-223.Research conclusions: AP protected PC-12 cells from LPS-induced inflammatory injury at least partially by down-regulating mi R-223 and then inactivating NF-?B pathway.This study provides evidence for further understanding the anti-inflammatory effects of AP and offers theoretical basis for deeply exploring the prevention and treatment of SCI by using AP. |
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