The Effect Of Ulinastain On Lipopolysaccharide-induced Microglia Activation And Neuroprotection

[BACKGROUD]:Neurodegenerative deseases are one kind of age-associated diseases withpathological features including the function and structure loss of neurons, whicheven lead to the death of neurons. Alzheimer’s disease (AD) and Parkinson’sdisease (PD) are typical neurodegenerative diseases. According to differentdamage types, clinical symptoms include diverse behavioral, psychiatric,cognitive, and motor disorders. In pathology, both inflammation and oxidativestress play an important role in neurodegeneration.Microglia have an important relationship with neurodegeneration asnervous system immune unit. Resting microglia have several functions fornervous system, such as support, surveillance, and repair. Microglia are sensitiveto environmental changes in the brain. Some stimulation can induce microgliaactivation. Active microglia produce many inflammatory chemokines and freeradicals, most of which have cell toxicity and their excessive accumulation can make neuronal degeneration, death, further lead to neurodegeneration.Activation of microglia is regulated by several signal pathways,such asJAK-STAT, MAPK, NF-kB, et, many of which have cross-talk with each other.Regulation of signal pathways plays a important role in microglia activation.Therefore it has important significance to inhibit the activation of microgliaduring the treatment and prevention of neurodegeneration.Microglia as neurodegeneration therapeutic targets has become a feasibleway. In previous studies, it has been confirmed that the activation of microgliacould inhibited by some pharmaceuticals, which have clinical crue andprotection effect to a certion extant. It has been confirmed that, ulinastain (UTI),a kind of protease inhibitor, has clear anti-inflammatory andoxidation resistance effect. However, whether it could suppress the activationof microglia is unknown, and we would discuss it in this research.[OBJECTIVE]We investigated the effect of UTI on microglia activation and spatialmemory though establishing in vitro and in vivo microglia activation model byLPS. Then we further investigated the signaling pathways involved.[METHODS]1. The vivo model of microglia cell activation was established by injection ofrats with LPS.2. The vitro model of microglia activation was established throughstimulating BV2cells by LPS.3. The changes of learning and memory function in rats were observedthrough Morris Water Maze. 4. Microglia cell morphology was observed byimmunohistochemistry.5. ELLSA was used to detect the release of TNF-α and IL-1β.6. Western Blot was used to detect the change of related signal pathways.[RESULTS]1. Establishment of microglia cell activation model induced by LPS.In in vivo experiments, rats received an intraperitoneal injection ofLPS.Then performance declined in the Morris Water Maze. Large number ofactivated microglia could be observed in the inland area byimmunohistochemistry and TNF-and IL-1β increased in brain tissue by ELISA.In in vitro study, LPS stimulation induced TNF-α and IL-1β release in BV2cells.2. The inhibitory effect of UTI on microglia activation induced by LPS.In in vivo experiments, Morris Water Maze results show that theperformance impairment induced by LPS was improved by UTI (100kU/kg).Immunohistochemical results show that LPS-induced microglia activation wasalso inhibited by UTI. Moreover, as shown by ELISA, both TNF-α and IL-1βrelease were inhibited. In vitro results show TNF-α and IL-1β release from BV2cells caused by LPS were alleviate by UTI.3. The signal transduction mechanism involved in the inhibitory effects of UTIon LPS-induced microglia activation.Both in vivo and in vitro resullts show that both MAPKs and JAK-STATpathway of hippocampus tissue and BV2cells were activated in response to LPS,which could be decreased by UTI. Further work shows that enhanced STAT3phosphorylation levels could be inhibited by inhibiting the activation of MAPKspathway. [CONCLUSION]1. LPS can make microglia activated, increase the release of inflammatoryfactors, and have effects on learning and memory functions.2. UTI could inhibit microglia activation, thereby reduce the release ofinflammatory factors and improve the function of learning and memory.3. The inhibitory effects of UTI on microglia activation may be due to itsinhibitory effects on the activation of MAPKs and JAK-STAT pathwayscaused by LPS. Furthermore, STAT may be the substrate of MAPKs.In conclusion, UTI has certain protective effects on nervous system, whichcan be new drug used for the treatment and the prevention of neurodegerativediseases.