OBJECTIVE We have recently reported that cysteinyl leukotriene(Cys LT) signaling plays an important role in microglial interleukin(IL)-1β secretion and subsequent neurotoxicity.The present study aimed to examine microglial morphological changes and the upstream molecular underlying IL~(-1)β production in Cys LT receptor agonist leukotriene D4(LTD4)-treated BV2 microglia in vitro.METHODS Twenty-four hours after murine microglial BV2 cells were stimulated with LTD4(1-100 nmol·L~(-1)),the cell proliferation and morphology were observed.The expression level of cysteinyl aspartate-specific protease 1(CASP1) protein was measured by Western blotin BV2 cells.In addition,BV2 cells were pretreated with or without CysLT1 receptor antagonist montelukast for 1 h and the effects of monte-lukaston LTD4-stimulated microglial activation and CASP1 expression were evaluated.RESULTS The number of BV2 cells had an increasing tendency after 24 h treatment with LTD4,but no significant differences were observed between the control and LTD4-treated cells(P>0.05).Under basal and resting conditions,BV2 microglial cells displayed a ramified morphology.However,LTD4 at 100 nmool·L~(-1) drove microglial morphological changes from a ramified towards an amoeboid shape.The expression of CASP1 protein was significantly upregulated in 100 nmool·L~(-1) LTD4-treated BV2 microglia(P<0.01).Furthermore,pretreatment with CysLT1 receptor antagonist montelukast prevented cell morphological changes and suppressed the increased CASP1 expression in LTD4-treated BV2 cells(P<0.05).CONCLUSION Cys LT receptor agonist LTD4 induces morphological changes and CASP1 expressionin BV2 microglia,which can be inhibited by CysLT1 antagonist.These results suggest the involvement of Cys LT signaling in microglial morphological changes and CASP1 expression. OBJECTIVE We have recently reported that cysteinyl leukotriene (Cys LT) signaling plays an important role in microglial interleukin (IL) -1β secretion and subsequent neurotoxicity. The present study aimed to examine microglial morphological changes and the upstream molecular underlying IL ~ (-1) β production in Cys LT receptor agonist leukotriene D4 (LTD4) -treated BV2 microglia in vitro. METHODS Twenty-four hours after murine microglial BV2 cells were stimulated with LTD4 (1-100 nmol·L -1), the cell proliferation and morphology were observed. The expression level of cysteinyl aspartate-specific protease 1 (CASP1) protein was measured by Western blotin BV2 cells. In addition, BV2 cells were pretreated with or without CysLT1 receptor antagonist montelukast for 1 h and the effects of monte- lukaston LTD4-stimulated microglial activation and CASP1 expression were obtained. RESULTS The number of BV2 cells had an increasing tendency after 24 h treatment with LTD4, but no significant differences were obs erved between the control and LTD4-treated cells (P> 0.05) .Under basal and resting conditions, BV2 microglial cells displayed a ramified morphology.However, LTD4 at 100 nmool·L -1 drove microglial morphological changes from a ramified towards an amoeboid shape.The expression of CASP1 protein was significantly upregulated in 100 nmol·L -1 LTD4-treated BV2 microglia (P <0.01) .Furthermore, pretreatment with CysLT1 receptor antagonist montelukast prevented cell morphological changes and suppressed the increased CASP1 expression in LTD4-treated BV2 cells (P <0.05) .CONCLUSION Cys LT receptor agonist LTD4 induces morphological changes and CASP1 expression in BV2 microglia, which can be inhibited by CysLT1 antagonist. this results suggest the involvement of Cys LT signaling in microglial morphological changes and CASP1 expression.