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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.
RESUMO
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.