Effect Of Electroacupuncture Pretreatment On Inhibiting NEK7-NLRP3 Inflammasome And Reducing Lung Injury In Sepsis ALI Rats

Objective:To investigate the effect of electroacupuncture（EA）pretreatment“Chize”（LU5）and“Zusanli”（ST36）points on reducing lung injury of ALI rats with sepsis by regulating NEK7-NLRP3 inflammasome.Methods:1.Grouping and model establishment of rats:40 SD rats were randomly divided into 4groups:control group,EA pretreatment+control group,model group,EA pretreatment+model group.Model group and EA pretreatment+model group were constructed by intraperitoneal injection of LPS（5mg/kg）.2.EA pretreatment method:One week before model preparation,EA pretreatment was performed at“Chize”and“Zusanli”points in both sides of the rats in the EA pretreatment+control group and EA pretreatment+model group.The stimulation parameters were density wave with frequency of 4 Hz/20 Hz and intensity of 1-2 m A,which was subject to slight tremor in the limbs of rats,30 min each time,once a day,and continuous treatment for 7 days.3.Index detection:The changes of lung function and lung histopathology in each group were observed.The wet/dry weight（W/D）ratio of lung tissue was calculated.The contents of myeloperoxidase（MPO）,malondialdehyde（MDA）,total antioxidant capacity（T-AOC）and superoxide dismutase（SOD）in lung tissues of rats were determined by the kits.The secretions of inflammatory factors interleukin-1β（IL-1β）and IL-18 in plasma and lung tissue were measured by ELISA method.The positive expression of ASC protein in the lung tissue of rats were observed by immunofluorescent staining.The expressions of NIMA-related kinase 7（NEK7）,NOD-like receptor family pyrin domain-containing protein 3（NLRP3）,Cysteine aspartuc acidspecific protease-1（Caspase-1）and IL-1βin lung tissues of rats in each group were detected by Western blotting.Results:1.In the LPS induced ALI model rats,the lung ventilation function of the model rats was significantly decreased compared with the control group,such as forced vital capacity（FVC）,forced inspiratory volume in 0.1 second(FEV_0.1),forced inspiratory volume in 0.3 second(FEV_0.3),FEV_0.1/FVC and FEV_0.3/FVC（P<0.01）;The histopathological observation showed that the alveolar structure was disordered,the alveolar septum thickened,and a large number of inflammatory cells infiltrated and red blood cells exudated.Compared with model group,EA pretreatment+model group significantly improved lung function（P<0.05,P<0.001）,pulmonary septum became thinner,inflammatory cell infiltration in lung tissue decreased,and red blood cell exudation decreased.2.Compared with the control group,the W/D ratio of lung tissue in model group was significantly increased（P<0.001）;The contents of MPO and MDA were significantly increased（P<0.001）,while the contents of T-AOC and SOD were significantly decreased（P<0.001）.The levels of inflammatory factors IL-1βand IL-18 in the plasma and lung tissue were significantly increased（P<0.001）.Compared with model group,the W/D ratio of lung tissue in EA pretreatment+model was significantly decreased（P<0.01）;The contents of MPO and MDA were significantly decreased（P<0.001）,while the contents of T-AOC and SOD were increased（P<0.05,P<0.001）.The levels of inflammatory factors IL-1βand IL-18 in plasma and lung tissue were decreased（P<0.01,P<0.001）.3.Compared with the control group,the positive expression of ASC in the lung tissue of model group were significantly increased（P<0.001）;The protein expressions of NEK7,NLRP3,Caspase-1 and IL-1βin lung tissue were significantly increased（P<0.001）.Compared with model group,the positive expression of ASC in lung tissue of rats in EA pretreatment+model group was reduced（P<0.001）.The protein expressions of NEK7,NLRP3,Caspase-1 and IL-1βin lung tissue were significantly decreased（P<0.05,P<0.01,P<0.001）.Conclusions:1.Increased activation of NLRP3 inflammatorites in lung tissue of sepsis ALI model rats.2.EA pretreatment can improve lung function,reduce pulmonary inflammatory response,pulmonary edema and oxidative stress in sepsis ALI model rats,which may be related to the inhibition of NEK7-NLRP3 inflammasome by EA.