Objective To observe the effect of NLRP3 inflammasome inhibitor MCC950 intervention on airway Muc5ac level in asthmatic mice, and to explore the role and mechanism of NLRP3 inflammasome in asthmatic airway mucus hypersecretion. Methods A total of 50 SPF grade BALB/c female mice aged 6 - 8 weeks were randomly divided into normal control group (NS group), asthma model group (AS group), dexamethasone group (Dex group), MCC950 high-dose intervention group (MH group) and MCC950 low-dose intervention group (ML group), with 10 mice in each group. Furthermore, the bronchoalveolar lavage fluid (BALF) of mice in each group was counted by total cell count, associated with white blood cell different count. In addition, the concentrations of interleukin (IL)-18 and IL-1β in BALF were tested by enzyme-linked immunosorbent assay; The lung tissues were prepared into paraffin-embedded sections, which were then subject to hematoxylin-eosin (HE) staining, Alcian blue-periodic acid Schiff base staining and Masson staining to observe the pathological changes of lung tissues. Immunohistochemistry was used to detect the protein expression levels of Muc5ac, NLRP3 and caspase-1 in lung tissues. Real-time quantitative polymerase chain reaction was performed to detect the relative mRNA expressions of Muc5ac, NLRP3 and Caspase-1 in lung tissues. Results Compared with NS group, AS group showed significant increase in total cell count of BALF, the percentage of eosinophils, the infiltration score of inflammatory cells around the airway, the positive relative staining area of airway mucus and the deposition area of airway collagen fibers in mice (P<0.05), upregulated protein expression levels of Muc5ac, NLRP3 and Caspase-1 in lung tissues (P<0.05), elevated relative mRNA expressions of Muc5ac, NLRP3 and Caspase-1 in lung tissues (P<0.05), and raised concentrations of IL-18 and IL-1β in BALF (P<0.05). While compared with AS group, the above indicators were reduced in MH group and ML group (P<0.05). Moreover, in relative to Dex group, these indicators were increased in MH group ML group (P<0.05). In addition, no statistically significant difference was observed in the aforementioned indications between MH group and ML group.Conclusions MCC950 intervention can inhibit airway inflammation and airway mucus secretion in asthmatic mice. Its mechanism is speculated to be related to the suppression of NLRP3, Caspase-1, IL-18 and IL-1β expressions, downregulation of Muc5ac expression, and inhibition in airway mucus hypersecretion.
Objective To investigate the inhibitory effects and related mechanisms of NOD like receptor protein 3 (NLRP-3) inflammasome inhibitor MCC950 on oxidative stress, inflammation, and pyroptosis in human esophageal epithelial cells (HEECs). MethodsHEECs cells were passaged and divided into blank control group, acid stimulation group (stimulated 3 times a day with pH 4 acidic medium for 15 minutes each time, cultured for 48 hours), bile salt stimulation group (stimulated 3 times a day with 400 μmol/L bile salt mixture for 15 minutes each time, cultured for 48 hours), lipopolysaccharide (LPS) group (stimulated with 10 μL of 100 ng/mL LPS for 48 hours), MCC950 group (stimulated HEECs cells with 10 μL of 7.5 ng/mL MCC950 for 4 hours, then stimulated with acid, bile hydrochloric acid, and LPS for 48 hours), and N-acetyl-L-cysteine (NAC) group (stimulated HEECs cells with 1 mmol/L NAC for 4 hours, then stimulated with acid, bile hydrochloric acid, and LPS and incubated for 48 hours). Three culture dishes were used in each group to detect the mRNA and protein expression levels of oxidative protein/antioxidant protein [Nox-4 (NADPH oxidase 4), nuclearfactor erythroidderived 2-like 2 (Nrf-2), heme oxygenase-1 (HO-1)], NLRP-3 signaling pathway [NLRP3/caspase-1/intereukin-1β (IL-1β)/intereukin-18 (IL-18)], and cell apoptosis pathway [caspase-4/caspase-5/GSDMD] using real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting experiments. Cell apoptosis were observed through Hoechst 33342 staining. ResultsMCC950 intervention (average optical density: 0.023) and NAC intervention (average optical density: 0.031) effectively inhibited HEECs apoptosis induced by acid (average optical density: 0.042), bile salt (average optical density: 0.047), and LPS (average optical density: 0.054). The results of RT-PCR and Western blotting experiments showed that MCC950 intervention and NAC intervention significantly inhibited the high expression of Nox-4 mRNA (MCC950:1.68±0.18, NAC: 1.62±0.17) and protein in HEECs cells induced by acid (1.00±0.05), bile salt (3.07±0.25), and LPS (3.52±0.37); And significantly upregulated the mRNA and protein expression levels of antioxidant proteins Nrf-2 (MCC950: 0.72±0.12, NAC: 0.57±0.12) and HO-1 (MCC950: 0.74±0.12, NAC: 0.57±0.12). MCC950 intervention and antioxidant NAC intervention effectively inhibited the mRNA and protein expression levels of acid stimulated, bile salt stimulated, and LPS induced HEECs cell NLRP-3 (MCC950 intervention: 1.58±0.06, NAC intervention: 1.47±0.09), ASC (MCC950 intervention: 1.56±0.09, NAC intervention: 1.93±0.17), caspase-1 (MCC950 intervention: 1.64± 0.13, NAC intervention: 1.96±0.20), IL-1β (MCC950 intervention: 1.66±0.18, NAC intervention: 1.82±0.20), IL-18 (MCC950 intervention: 1.58±0.13, NAC intervention: 1.84±0.16) and other indicators. MCC950 intervention and antioxidant NAC intervention effectively inhibited the mRNA and protein expression levels of apoptosis pathway markers such as caspase-4 (MCC950 intervention:1.51±0.03, NAC intervention: 1.61±0.12), caspase-5(MCC950 intervention: 1.38±0.13, NAC intervention: 1.64±0.21), and GSDMD (MCC950 intervention: 1.41±0.04, NAC intervention: 1.54±0.10) induced by acid stimulation, bile salt stimulation, and LPS in HEECs cells. ConclusionAcid, bile salts, and LPS can all induce the overexpression of oxidative stress markers in HEECs, reduce the expression of antioxidant proteins, and activate the NLRP3 inflammasome signaling pathway and cell pyroptosis pathway, promoting cellular inflammatory damage, but MCC950 has a protective effect.