Gastrodin Inhibits Inflammasome Through The JAK/STAT3 Signal Pathways In TNA2 Astrocytes And Reactive Astrocytes In Experimentally Induced Cerebral Ischemia In Rats

Objective:This study was aimed to determine Gastrodin(GAS)and its underlying signaling pathway involved in suppression of inflammasome specifically in reactive astrocytes that are featured prominently in different neurological conditions or diseases including cerebral ischemia.Methods:For this purpose,TNA2 astrocytes in cultures were exposed to oxygen glucose deprivation(OGD)mimicking hypoxic cerebral ischemia.Separately,TNA2 cells were pretreated with GAS prior to OGD exposure.Additionally,Stattic,an inhibitor of STAT3 signaling pathway,was used to ascertain its involvement in regulating inflammasome in astrocytes exposed to OGD.In parallel to the above,adult rats subjected to middle cerebral artery occlusion(MCAO)with or without GAS pretreatment were sacrificed at different time points to determine the effects of GAS on astrocyte inflammasome.TNA2 astrocytes in different treatments as well as reactive astrocytes in MCAO were processed for immunofluorescence labeling and Western blot analysis for various protein markers.Results:In MCAO,GAS was found to effectively attenuate inflammasome and p-STAT3 protein level and immunofluorescence intensity in astrocytes.In the latter,protein expression levels of p-STAT3,NLRP3 and NLRC4 were markedly increased in TNA2 astrocytes exposed to OGD.Remarkably,the expression levels of these biomarkers were significantly suppressed by GAS.Of note,GAS especially at dose 20 ?M inhibited NLRP3 and NLRC4 expression level most substantially.Moreover,GAS inhibited the downstream proteins caspase-1 and IL-18.Concomitantly,GAS significantly suppressed the expression of JAK/STAT3 and NF-?B signaling pathway.It is noteworthy that Stattic at dose 100 ?M inhibited STAT3 pathway and NF-?B activation in TNA2 astrocytes,an effect that was shared by GAS.Conclusion(s):Arising from the above,it is concluded that GAS is anti-inflammatory as it effectively suppresses inflammasome in OGD stimulated astrocytes as well as in reactive astrocytes in MCAO via STAT3 and NF-?B signaling expression coupled with decreased expression of caspase-1 and IL-18.