| Objective To explore the effect of lactic acid on immune inflammation and permeability of bone marrow endothelial cells in sepsis,and to clarify its mechanism of promoting neutrophil chemotaxis,so as to provide experimental data for the study of sepsis.Methods 1.Clinical study: Divided into Spesis group and healthy control group(10cases in each group).Peripheral blood was collected on the first day of hospitalization,and the blood neutrophil count and lactic acid content were detected.The expression of MCT4 and GPR81 mRNA was detected by fluorescence quantitative RT-PCR.2.Animal study:Divided into four groups:(1)Normal control group(NC group): intraperitoneal injection of saline equal to lipopolysaccharide(LPS);(2)LPS sepsis rat model group(LPS group):intraperitoneal injection of LPS 5mg/kg.(3)LPS sepsis plus lactic acid intervention model group(LPS+Lac group): LPS was injected intraperitoneally for 1 hour and then lactic acid(10mg/kg)was injected intraperitoneally.(4)LPS septic rats plus lactic acid and GPR81 receptor inhibitor intervention group(LPS+Lac+GPR81￣group):LPS was injected intraperitoneally with GPR81 receptor inhibitor(20 mg/kg)for 1 hour,and lactic acid(10mg/kg)was injected intraperitoneally after 1 hour;Eight rats in each group.Lung HE staining was used to observe pathological changes.The contents of IL-6,IL-12,IL-18 and lactic acid in peripheral blood were detected by ELISA.The expressions of CD16,Ly6 G mRNA,MCT4,GPR81,c AMP,Epac-1 and VE-cadherin mRNA in lung tissue were detected by q PCR.Results: Clinical study: The absolute number of neutrophils and the content of lactic acid in peripheral blood in Sepsis group were significantly higher than those in NC group(t=4.446,4.167,all P<0.001),and the expressions of MCT4 and GPR81 mRNA in peripheral blood in Sepsis group were significantly higher than those in NC group(t=5.519,10.00,P<0.0001).Animal research: 1.HE staining showed that the alveolar structure in NC group was complete,and there was no inflammatory cells and fluid exudation in alveolar cavity and interstitial space.In LPS group,lung tissue was congested and edematous,alveolar septum was thickened,and a large number of inflammatory cells infiltrated.In LPS+Lac group,lung tissue was congested and edematous,alveolar septum was thickened,and inflammatory cell infiltration was significantly worse than that in LPS group.In LPS+Lac+GPR81￣group,the lung tissue was congested and edematous,the alveolar septum was thickened,and the inflammatory cell infiltration was less than that in LPS group.22.The absolute number of granulocytes and lactic acid content in peripheral blood in LPS group were significantly higher than those in NC group(t=9.267,t=4.823,P<0.05,P<0.0001),and the absolute number of granulocytes and lactic acid content in LPS+Lac group were significantly higher than those in LPS group(t=4.421,t=9.170,P<0.0001).t=6.346、10.69,P<0.05.The contents of IL-6,IL-12 and IL-18 in peripheral blood in LPS group were significantly higher than those in NC group(t=7.59,6.751 and 5.195,P<0.05),and the contents of IL-6 and IL-18 in LPS+Lac group were significantly higher than those in LPS group(5.463,6.543,P<0.05);The expressions of CD16 and Ly6 G,GPR81 and MCT4 mRNA in LPS group were significantly higher than those in NC group(t=6.341,6.271,P < 0.001;T=4.170,t=4.927,P<0.05),the LPS+Lac group was significantly higher than the LPS group(t=15.77,16.15,P < 0.0001;T=6.148,6.902,P<0.05),and LPS+Lac+GPR81￣ group was significantly lower than LPS group and LPS+LAC group(t=4.021,4.373,4.401,11.30,P < 0.05;t=13.52、14.18,4.036、10.18,P<0.05).The mRNA levels of c AMP,Epac-1 and VE-cadherin mRNA LPS group were significantly lower than those in NC group(t=4.882,6.687,6.279,P<0.05),and those in LPA+Lac group were significantly lower than those in LPS group(t=4.882,6.687,6.297,P<0.05).The mrna of VE-cadherin mRNA LPS+Lac+GPR81￣ group was significantly higher than that in LPS group(t=6.078,P<0.05),and the mRNA of c AMP,Epac-1 and VE-cadherin was significantly higher than that in LPS+lac group(t=6.204,7.869,12.55,P<0.05).Conclusion 1.Clinical study: Peripheral neutrophils and blood lactic acid in patients with sepsis increased significantly,and the expression of MCT4/GPR81 increased significantly.2.Animal studies:(1)Lactic acid increased the expression of inflammatory factors and peripheral neutrophils in LPS sepsis model rats.(2)Lactic acid increased the expression of MCT4/Lac/GPR81 mRNA of lactate transport system in LPS sepsis model rats,and decreased the expression of c AMP/Epac-1/VE-cadherin mRNA related to vascular permeability.It shows that lactic acid can increase vascular endothelial permeability and enhance neutrophil chemotaxis by up-regulating GPR81 mRNA. |
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