ABSTRACT
Silicosis is a leading cause of occupational disease-related morbidity and mortality worldwide, but the molecular basis underlying its development remains unclear. An accumulating body of evidence supports gasdermin D (GSDMD)-mediated pyroptosis as a key component in the development of various pulmonary diseases. However, there is little experimental evidence connecting silicosis and GSDMD-driven pyroptosis. In this work, we investigated the role of GSDMD-mediated pyroptosis in silicosis. Single-cell RNA sequencing of healthy and silicosis human and murine lung tissues indicated that GSDMD-induced pyroptosis in macrophages was relevant to silicosis progression. Through microscopy we then observed morphological alterations of pyroptosis in macrophages treated with silica. Measurement of interleukin-1β release, lactic dehydrogenase activity, and real-time propidium iodide staining further revealed that silica induced pyroptosis of macrophages. Additionally, we verified that both canonical (caspase-1-mediated) and non-canonical (caspase-4/5/11-mediated) signaling pathways mediated silica-induced pyroptosis activation, in vivo and in vitro. Notably, Gsdmd knockout mice exhibited dramatically alleviated silicosis phenotypes, which highlighted the pivotal role of pyroptosis in this disease. Taken together, our results demonstrated that macrophages underwent GSDMD-dependent pyroptosis in silicosis and inhibition of this process could serve as a viable clinical strategy for mitigating silicosis.
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Objective To investigate the protective effect of Carbachol on hyperoxia-induced acute lung injury (HALI) in mice and its related mechanisms. Methods Thirty-two healthy male ICR mice were randomly divided into four groups:control group, hyperoxia exposure three days group (HO3d group), hyperoxia exposure three days + Carbachol group (HO3d+Carba group), and Carbachol group (Carba group), eight mice in each group. The pathological changes of lung tissue in each group were observed under light microscope after the models were completed in each group.The expression of TLR4 and NF-κB protein in lung tissues were detected by Western blot, and the expression of HMGB-1 and TNF-α mRNA in lung tissues by RT-PCR. LSD-t test was used for sample pairwise comparison, and one-way ANOVA for intergroup comparison. P<0.05 was considered statistically significant. Results There was no statistical difference between the control group and the Carba group (P> 0.05), and no obvious abnormal changes in lung tissue structure. The expression of TLR4, NF-κB protein and HMGB-1 and TNF-α mRNA in the HO3d group were significantly higher than those in the control group (P<0.01), and there were obvious bleeding on the surface of the lung tissue and severe pathological damage. The expression of TLR4,NF-κB protein and HMGB-1 and TNF-α mRNA in the HO3d+Carba group were significantly lower than those in the HO3d group(P<0.01), while lung tissue damage degree was also lower than that in the HO3d group. Conclusions Hyperoxia can increase the expression of TLR4 and NF-κB in lung tissues, and cause inflammatory injury in lung tissue. Carbachol can reduce the release of HMGB-1 and TNF-α inflammatory factors in hyperoxia-induced acute lung injury, and its mechanism is related to the inhibition of TLR4/NF-κB signal pathway, which has a protective effect on HALI.
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Objective To investigate both in mechanism of hyperoxia-induced acute lung injury (HALI) by vivo experiment,to observe the Bruton' s tyrosine kinase (Btk) and nuclear factor kappa B (NF-κB) signals expression level.Methods Total of 72 healthy male Kunming mice were randomly (random number) divided into four groups:air control group,hyperoxia exposure 3 days group (H3d group),hyperoxia exposure 3 days + inhibitor group (H3d + Ⅰ group) and inhibitor groups.Then the pathological changes of lung tissues were observed under light microscope;The total protein content (TP) of bronchoalveolar lavage fluid (BALF) and wet/dry weight ratio (W/D) of lung were detected;The protein expression of Btk,p-Btk,pNF-κB p65 were mersured by Western blot;tlhe mRNA level of IL-6 was determined by real-time polymerase chain reaction (qRT-PCR);the level of monocyte chemoattractant protein-1 (MCP-1) in serum was detected by enzyme-linked immunosorbent assay (ELISA).Statistcal significance was determined by 1-way ANOVA.Results There were no significant difference in the data between the control group and the inhibitor group (P ＞ 0.05).The pathological injury in light microscope,content of total protein in BALF,W/D ratio of lung tissues in H3d group were significantly higher than H3d + Ⅰ group (Respectively P =O.002,P =0.000).Western blot analysis showed that expression of Btk,p-Btk,pNF-κB p65 in H3d group were significantly higher than those in H3d + Ⅰ group (Respectively P =0.002,P =0.013,P =0.000).RT-qPCR results showed that the expression of IL-6 mRNA in H3d group were significantly higher than control group (P =0.004),inhibitor group (P =0.000) and H3d + Ⅰ group (P =0.021).In addition,The serum MCP-1 levels in H3d group were higher markely than the control group (P =0.002),inhibitor group (P =0.000) and H3d + Ⅰ group (P =0.009).The correlation analysis showed that pNF-κB p65 were positively correlated wiht Btk and p-Btk (r =0.902 and 0.954,P ＜ 0.01).Conclusions Btk may trigger the release of IL-6 and MCP-1 by mediating the signaling pathway of NF-κB in vivo study,which was most important in the occurrence of HALI.Therefore,inhibiting the Btk activity would alleviate the severity of lung injury effectively.
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Objective To observe the content of macrophage inflammatory protein-1α(MIP-1α)in plasma and bronchoalveolar lavage fluid (BALF) and the expressions of MIP-1α mRNA and nuclear factor-kappa B( NFκB)p65 mRNA in the lung of rats subjected to mechanical ventilation with high tidal volume. Method Thirty-two healthy Wistar rats were randomly ( random number) divided into control group, ventilator induced lung injury (VILI) group,dexamethasone (DEX) group and budesonide (BUD) group. The content of MIP-1α in plasma and BALF were measured with ELJSA and the expressions of MIP-1α mRNA and NF-κBp65 mRNA in lung of rat were detected by RT-PCR. The data distributed were expressed as (-x) ± s and were compared among 4 groups. Furthermore, the correlation between the content of MIP-1α and the expression of MIP-1α mRNA, and the correlation between the expression of MIP-1α mRNA and the expression of NF-κBp65 mRNA were analyzed in the latter three groups. Results With lessened lung injury ,the content of MIP-1αin plasma and BALF and the expressions of MIP-1α mRNA and NF-κBp65 mRNA in lungs of rats of DEX and BUD groups were significantly lower than those in VILI group ( P ＜ 0.001 ). Although the content of MIP-1α in plasma and BALF and the expressions of MIP-1α mRNA and NF-κBp65 mRNA in lungs of rats of BUD group were higher than those of DEX group, but no significant differences were found between them ( P ＞ 0.05). Correlation study showed that positive correlations were xisted between the MIP-1α in plasma and the expression of MIP-1α mRNA in the lungs ( r = 0.895, P ＜ 0.05)and between the expression of MIP-1α mRNA and the expression of NF-κBp65 mRNA in the lungs ( r=0.801, P ＜ 0.05). Conclusions Glucocorticoid could down-regulate the expression of MIP-1α mRNA by inhibiting the activity of NF-κB in the lungs and may have preventive and therapeutic effect to VILI to some extent. The effect of glucocorticoid used locally against VILI is simnilar to that of systemic administration with lesser adverse reactions.
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Objective To investigate the effects of different tidal volume ventilation on acute lung injury in rats. Methods Thlrty-two normal Wistar rats were randomly divided into four groups:control group,low tidal volume group(L- V_T),conventional tidal volume group(C-V_T)and high tidal volume group(H-V_T).The pathologic changes of the lungs were observed under macrography,light and electron microscope.The blood gas analysis(PaO_2),the counts of neutrophils (PMN),the levels of protein and the myloperoxidase(MPO)activities in bronchoalveolar lavage fluid(BALF)were measured by biochemical methods respectively.Results There were no distinct pathological differences between L-V_T group and control group under macrography,light and electron microscope.In the C-V_T and H-V_T groups,there were different degree of lung injuries under light and electron microscope,their PMN,MPO activity and protein level in BALF were significantly higher than those of control and L-V_T groups and their PaO_2 were significantly lower than those of control and L- V_T groups(P＜0.01,P＜0.05).The MPO activity and the protein level in BALF were also significantly higher than those of C-VT group(P＜0.01)Of the above indexes,there were no statistical differences between L-V_T group and control group(P＞0.05).Conclusion Conventional tidal volume ventilation alone,without any lung-protective strategy, could produce injuries to the normal lung tissues,while low tidal volume ventilation hadn't effects on them.The injury effects produced by mechanical ventilation was closely related to the recruitment and activation of neutrephils in the lung.