Effects Of Kadsura Pepper Stem On The Expression Of IL-1βand TNF-αin Microglia Induced By Oligomeric Aβ_1-42

BackgroundAlzheimer’s disease (AD) is a progressive neurodegenerative disease gradually destroying memory and cognitive functions. One of the pathological features of Alzheimer’s disease is the neuritic plaques. It is now generally recognized that neuroinflammation probably plays a prominent role in AD progression. Amyloidβ1-42(Aβ1.42) is the main component of neuritic plaques, and may play an important role in the activation of microglia and excretion of prolammatory cytokines such as IL-1β and TNF-a.The effects of soluble Aβ1-42oligomers may be more important. These inflammatory cytokines can cause inflammatory damage to neurons, which leads to AD.The kadsura pepper stem is dry pepper plant wind vine,which has anti-inflammatory and analgesic effects. Through observing the impact of oligomeric Aβ1-42on the release of proinflammatory cytokines and the effect of kadsura pepper stem extracts,this experiment was aimed to further elucidate the mechanism of AD and find effective treatment of AD.ObjectiveThe experiment was designed to observe the impact of oligomeric Aβ1-42on the excretion of IL-1β and TNF-a in microglia cells, and to investigate the effect of piper kadsura ohwi extracts on microglia actived by oligomeric Aβ1-42.Methods1.Microglia cells were cultured (recovery, passage, cryopreservation) in vitro; 2. The soluble oligomeric Aβ1-42was prepared and observed to insure its stability by the electron microscope;3. Microglia cells were randomly divided into3groups:the contrast group(with no intervention), Aβ1-42group(intervented by oligomeric Aβ1-42）Aβ1-42+kadsura pepper stem extracts group(intervented by oligomeric Aβ1-42and kadsura pepper stem extracts).48hours later, levels of the expression of IL-1β and TNF-α were determined by Western blot.Results1.Microglia cells cultured in vitro have a branched, ramified morphology.After a pathological event,these "resting" cells undergo a transformation and acquire a amoeboid morphology.2. After2weeks of preservation at4℃, oligomeric Aβ1-42were observed under the electron microscope.They have a monomer or spherical form and no fiber formation was found.3. Western blot showed that Aβ1-42group[(32.0±3.6)(83.3±8.5)] had an increased expression of TNF-α and IL-1β than the blank contrast group[(2.6±1.7)(25.2±13.9),](t=11.74, P=0.000,t=7.46, P=0.000), and the Aβ1-42+kadsura pepper stem extracts group(21.7±4.5)[(59.3±2.7),] had a decreased expression of TNF-α and IL-1β than the Aβ1-42group(t=4.38, P=0.005,t=3.08, P=0.022),There were significant differences between the two groupsConclusion1.The overexpression of IL-1β and TNF-α in microglia activated by oligomeric Aβ1-42can be inhibited by kadsura pepper stem extracts.2.The formations of oligomer Aβ1-42prepared in this experiment had no change after2weeks and can be used to build a model of AD brain microenvironment.