Correlation analysis between the expression of cannabinoid 2 receptor and the related indicators of pyroptosis in sepsis / 中华急诊医学杂志

Objective:To explore the correlation between cannabinoid 2 receptor (CB2R) and pyroptosis-related indicators in mice with septic lung injury.Methods:Mice were randomly (ramdon number) divided into four groups ( n=6 per group) sham operation group (sham), mild sepsis group (ALIMi), moderate sepsis group (ALIMo) and severe sepsis group (ALIS). The model of septic lung injury was established by cecal ligation and puncture. The wet-dry weight ratio of lung tissues and lung injury scores were measured 12 hours after operation. The expression of CB2R protein was measured by western blot, and the expression of mRNA of CB2R, NLRP3, caspase-1/11, GSDMD were detected by RT-PCR. Meanwhile ELISA was used to measure the level of inflammatory factor IL-6 and TNF-α. SPSS 22.0 software was used for data analysis. Multiple comparison was analyzed by one-way analysis of variance (one-way ANOVA) and comparison between two groups was performed by LSD test or Games-Howell test. Then, the correlation between the expression of CB2R mRNA and the level of inflammatory cytokines as well as the expression of the pyroptosis-related indicators mRNA was analyzed by pearson correlation analysis, respectively. Results:The statistical value F was obtained by one-way ANOVA and comparison between two groups was performed. Compared to sham group, all above indicators increased with the aggravation of inflammation in the sepsis groups ( P<0.05). Compared to ALIMi group, the concentrations of IL-6 [(277.31±41.07) vs.(140.09±27.56), P<0.05] and TNF-α [(501.09±73.91) vs. (261.36±40.73), P<0.05] in lung tissue homogenate increased in ALIMo group. And the level of CB2mRNA [(2.99±0.28) vs. (2.02±0.19), P<0.05], the expression of CB2 protein [(0.44±0.08) vs.(0.23±0.05), P<0.05] and the level of NLRP3 [(2.53±0.26) vs.(1.61±0.15), P<0.05], caspase-1 [(6.02±0.35) vs.(3.60±0.38), P<0.05], caspase-11 [(11.43±0.83) vs.(6.30±0.65), P<0.05] and GSDMD [(10.46±0.62) vs. (5.67±0.54), P<0.05] mRNA also increased. Compared to ALIMo group, the concentrations of IL-6 [(475.90±67.65) vs. (277.31±41.07), P<0.05] and TNF-α [(713.93±58.85) vs. (501.09±73.91), P<0.05] in lung tissue homogenate increased in ALIS group. And the level of CB2mRNA [(4.00±0.19) vs.(2.99±0.28), P<0.05], the expression of CB2 protein [(0.61±0.05) vs.(0.44±0.08), P<0.05] and the level of NLRP3 [(4.75±0.40) vs.(2.53±0.26), P<0.05], caspase-1 [(8.76±0.72) vs.(6.02±0.35), P<0.05], caspase-11 [(16.31±1.13) vs.(11.43±0.83), P<0.05] and GSDMD [(16.46±1.22) vs. (10.46±0.62), P<0.05] mRNA also increased. Furthermore, correlation analysis showed that there was a highly positive correlation between the expression of CB2R mRNA and the expression of mRNA of NLRP3, caspase-1/11, and GSDMD respectively ( r>0.9, P<0.01). Conclusion:The correlation between the aggravation of inflammation, the indicators of pyroptosis and CB2R mRNA was highly positive in different degrees of septic lung injury. Consequently, CB2R may play a role in the regulatory process of inflammation.