Intravenous Human Embryonic Stem Cell-derived Mesenchymal Stem Cells Suppress NLRP3 Inflammasome-mediated Neurological Deficits In Ischemic Stroke

Objective: Ischemic stroke is a neurological dysfunction disorder caused by cerebrovascular accidents.With incidence increasing every year,it has a significant impact on public health and health-related quality of life in patients.Because of its narrow therapeutic window,a large number of patients missed the treatment opportunity,leaving lifelong disability.Study shows that mesenchymal stem cells enhances functional recovery in ischemic stroke,but the mechanism is still unknown.In recent years evidence has accumulated that pyroptosis plays a key role in neuronal injury after ischemic stroke.Therefore,this study explores whether hES-MSC transplantation therapy can alleviate neurological injury after acute ischemic stroke by inhibiting pyroptosis.Methods: Cerebral ischemia was induced by 90 min of transient middle cerebral artery occlusion(t MCAO)in rats.Rats with modified Neurological severity scores(m NSS)between7-12 points were randomly divided into 3 groups(hES-MSC group n=14,NLRP3inhibitor(MCC950)group n=14,control group n=14),another is sham group(n=12).To evaluate the therapeutic effect,behavioral test was performed by m NSS at 1,3,6days after t MCAO.Cerebral infarct volume was detected by TTC staining at 3 days after t MCAO.Immunofluorescence staining was performed to Neu N,GFAP,DCX,NLRP3,while double immunofluorescence staining was used for Brd U/Neu N,Brd U/GFAP,Brd U/Iba1 at 7days after t MCAO.The expressions of NLRP3,caspase-1,and ASC were examined using Western blot,and the m RNA expression of NLRP3,ASC,Caspase-1,IL-1β,IL-18,was detected by q RT-PCR.Results:(1)The m NSS score of hES-MSC group was lower than that of the control group(P<0.05)and the infarct volume decreases(P<0.05).(2)hES-MSC functioned to promote neuronal survival(P<0.05)and enhanced neuron production(P<0.05).(3)hES-MSC suppressed glial activation and proliferation(P<0.05).(4)hES-MSC decreased the m RNA levels of NLRP3,ASC,Caspase-1,IL-1 β,and IL-18(P<0.05),and reduced NLRP3 inflammasome protein expressions(P<0.05).(5)NLRP3 inflammasome activation and the subsequent pyroptosis were associated with neurological deterioration following ischemic stroke,and promoted glial activation and proliferation(P<0.05).Conclusion: hES-MSC transplantation therapy can alleviate neurological injury after acute ischemic stroke by inhibiting the NLRP3 inflammasome-mediated cell pyroptosis.