Expression Of NLRP3Inflammasome In Imiquimod-induced Psoriasiform Inflammation Of BALB/c Mice And Effects Of Mustard Seed (Sinapis Alba Linn) On It

BackgroundImiquimod-induced psoriasiform inflammation of BALB/c mice can be causedby the great amounts of IFN-α released by pDC as well as IL-23/IL-17axis andIL-22. NLRP3(also known as NALP3) inflammasome which has received currentattention is one of the pattern recognition receptors (PRRs) of the innate immunesystem. Various danger and stress signals activate NLRP3inflammasome, leading tothe processing and secretion of the pro-inflammatory cytokines such as caspase-1,IL-1β, and IL-18, and further triggering the activation of T cells and NK cells andthe release of IFN-γand TNF-α，cells and cytokines which play significant roles inthe pathogenesis of psoriasis. It is yet unclear that whether NLRP3inflammasome isinvolved in the development of Imiquimod-induced psoriasiform inflammation ofBALB/c mice, and further investigation is needed.Mustard seed (Sinapis Alba Linn) has certain properties of anticancer, antiaging,and antioxidation. Our previous research finds that mustard seed attenuates the lesionsof Imiquimod-induced psoriasiform inflammation of BALB/c mice through inhibitingthe actions of reactive oxygen species (ROS) and IL-23/IL-17axis. On this basis ourstudy investigates the effects of mustard seeds on the Imiquimod-inducedpsoriasiform inflammation of BALB/c mice.Objectives1. To establish the model of Imiquimod-induced psoriasiform Inflammation ofBALB/c mice.2. To investigate the role of NLRP3inflammasome in Imiquimod-inducedpsoriasiform Inflammation of BALB/c mice.3. To investigate the effects of mustard seed on NLRP3inflammasome in Imiquimod-induced psoriasiform inflammation of BALB/c mice.MethodsThirty mice were randomly and equally divided into three groups: blank controlgroup (normal forage and vehicle), model control group (normal forage andImiquimod cream), and experimental group (5%mustard seed forage and Imiquimodcream). RT-PCR was applied to detect the mRNA expression of NLRP3, ASC,caspase-1, and caspase-11. Immunohistochemistry was performed to observe theexpression and distribution of ASC and caspase-1. ELISA was applied to test theserum levels of IL-1β and IL-18.Results1. Compared with the blank control group, the mRNA levels of lesional NLRP3,ASC, caspase-1, and caspase-11, protein levels of ASC and caspase-1, and serumlevels of IL-1β and IL-18in Imiquimod-induced psoriasiform inflammation of micewas increased(P <0.05).2. Compared to the model control group, the mRNA levels of lesional NLRP3,ASC, caspase-1, and caspase-11, protein levels of ASC and caspase-1, and serumlevels of IL-1β and IL-18in Imiquimod-induced psoriasiform inflammation of micewere attenuated by mustard seed, which was reflected by the decrease of them.Conclusions1. NLRP3inflammasome is involved in Imiquimod-induced psoriasiformInflammation of BALB/c mice.2. Mustard seed may suppress the Imiquimod-induced psoriasiforminflammation induced by IL-1β and IL-18through down-regulating the expressionof NLRP3inflammasome.