Verbascoside Attenuates Acute Inflammatory Injury Caused By An Intracerebral Hemorrhage Through The Suppression Of NLRP3

Objective: Intracerebral hemorrhage(ICH)is a serious cerebrovascular disease with a high rate of death and disability,which seriously threatens people’s physical and mental health.ICH is more common among Asians,senior citizens,men,and low-and middle-income countries.The mortality rate of ICH is very high(40% at 1 month and 54% at 1 year),and only 12% to 39%of survivors can achieve long-term survival.Risk factors for ICH are high blood pressure,long term smoking,excessive alcohol consumption,hypercholesterolemia,and certain medications.Old age,men,Asian ethnicity,chronic kidney disease,cerebral amyloid angiopathy(CAA),and cerebral microhemorrhage(CMB)increase the risk of ICH.The clinical manifestations vary according to the size and location of the hematoma and the degree of intraventricular hemorrhage.After intracerebral hemorrhage,under the stimulation of various factors,it will arouse a serious inflammatory response in the brain,and the continuous inflammation will cause the death of brain cells,and also promote secondary brain damage.Secondary injuries such as cerebral edema play an important role in the neurological decline of ICH patients.This is triggered by the presence of blood in the parenchyma,which activates cytotoxic,excitotoxic,oxidative and inflammatory pathways.An inflammatory response occurs immediately after the presence of blood components is detected in the parenchyma,which is characterized by the mobilization and activation of inflammatory cells.It is believed that microglia and astrocytes are the first inflammatory cells to respond to exuding blood.The activation of microglia leads to the infiltration of various circulating immune cells,most notably macrophages and T cells.Subsequently,this leads to inflammatory cytokines(such as interleukin-1β[IL-1β] and tumor necrosis factor-α [TNF-α]),chemokines,free radicals,and other toxic chemicals that may coordinate their effects through transcription factors The substance releases nuclear factor-κB(NF-κB).NF-κB targets include cytokines,chemokines,various adhesion molecules,cell surface receptors,and inflammatory enzyme genes(for example,Inducible nitric oxide synthase [i NOS],Cyclooxygenase 2 [COX-2] ],Phospholipase A2 [PLA2]).Together with the products of cell death,these chemicals further activate the resident and migrating lymphocytes,leading to increased lymphocyte infiltration and continuous inflammation.More and more evidences show that this inflammatory response promotes the formation of edema through the increase in the permeability of the blood-brain barrier(BBB)around the hematoma,thereby intensifying the mass effect and intensifying the cell death process through secondary ischemia.And further produce inflammation tissue to the surrounding brain.Verbascoside(VB)is a traditional Chinese medicine monomer compound mainly existing in Cistanche deserticola,and it has been found to have a variety of biological functions.Moreover,previous studies have shown that VB can improve the recovery of neuronal function after spinal cord injury in rats.In our study,we intend to investigate whether VB can inhibit the acute inflammatory response after ICH by targeting NLRP3,and explore its potential molecular mechanism.Methods: The mouse brain was stereotactically injected with type VII collagenase to construct a brain hemorrhage model;Garcia’s method was used to evaluate the damage of brain function in mice;the volume of brain hemorrhage in mice was detected by gross sectioning of mouse brains;brain edema in mice was detected by wet and dry ratio method;apoptosis in mice was detected by TUNEL staining;m RNA and protein expression in samples were detected by RT-PCR and Western Blot and immunofluorescence staining;the effect of VB was detected by co-culture of BV2 and primary neurons in mice using the transwell technique;and the effect of VB was detected using NLRP3 knockout mice.The co-culture of BV2 and primary neurons in mice was performed by transwell technique,and the effect of VB was detected in NLRP3 knockout mice.Results: VB improved neurological deficits caused by cerebral hemorrhage and reduced cerebral hemorrhage volume and cerebral edema,and reduced apoptosis;VB inhibited NLRP3 and its downstream inflammatory effectors after cerebral hemorrhage and reduced microglia activation,thereby increasing neuronal survival;NLRP3 deficiency attenuated the above-mentioned ameliorative effects of VB on cerebral hemorrhage in mice.Conclusion: VB inhibits the inflammatory response after ICH by inhibiting NLRP3,leading to the treatment of mouse cerebral hemorrhage in mice.