| Objective:To study the alteration of MK2/NF-κB/Lin28/let-7e/IL-6 signaling pathway in lung tissue fibrosis in rats exposed to different coal mine dusts through whole animal experiments.Methods:96 healthy male SD rats,weighing 180-220 g,were randomly divided into control group,coal dust group,coal-silica dust group and silica dust group of 8 rats each for 1,3 and 6 months.Non-exposed tracheal intubation was used to infuse normal saline,50 g / L coal dust,coal-silica dust and silica dust at one time for modeling.After 1,3 and6 months,the lung function of rats was monitored in the state of anesthesia,and lung lavage fluid and lung tissue of rats were collected.The changes of respiratory function in rats exposed to dust were observed by pulmonary function monitoring.HE staining and Masson staining were used to observe lung fibrosis of rats exposed to dust.ELISA was used to detect the changes of inflammatory factor IL-6 in the lungs of rats exposed to dust.The q RT-PCR was used to detect the changes of let-7e levels in the lungs of rats exposed to dust.Western Blotting was used to detect the changes of MK2,NF-κB and Lin28 proteins expression in the lungs of rats exposed to dust.Results:1.During the process of dust exposure,the rats did not die,the diet and activity of the rats in the control group were normal,and the rats in the dust exposure groups had a reduced diet and were irritable.In the 1-month group and the 3-month group,there was no significant difference in the changes of lung organ coefficient between the dust exposed groups and the control group(P > 0.05).In the 6-month group,the lung organ coefficient of the rats in the silica dust group were significantly higher than those of the control group and the coal dust group(P < 0.05).2.In the 1-month group,there was no significant difference in FVC and FEV0.1/ FVC between the dust exposed groups and the control group(P > 0.05).Compared with the control group,the PEF of the rats in the silica dust group decreased(P < 0.05).Compared with the control group,the MMEF of the rats in the coal-silica dust group and silica dust group decreased(P < 0.05).In the 3-month group,there was no difference in FVC between the dust exposed groups and the control group(P > 0.05).FEV0.1 / FVC decreased in the silica dust group compared with other groups(P < 0.05).Compared with the control group,PEF and MMEF of rats in the coal-silica dust group and silica dust group decreased(P < 0.05).In the 6-month group,compared with the control group,the FVC of rats in the coal-silica dust group and silica dust group decreased(P > 0.05).Compared with the control group,FEV0.1 / FVC、PEF and MMEF were decreased in the dust exposed groups(P < 0.05).In the coal dust group,there was no significant difference in FVC and PEF between each month(P > 0.05).Compared with 1-month group,FEV0.1 / FVC decreased in 6-month group(P < 0.05).Compared with the 1-month group and the 3-month group,the MMEF of the 6-month group decreased(P < 0.05).In the coal-silica dust group,compared with the 1-month group,the FVC of the 6-month group decreased significantly(P < 0.05);the FEV0.1 /FVC,MMEF and PEF in the 6-month group were significantly lower than those in the1-month group and the 3-month group(P < 0.05).In the silica dust group,compared with the 1-month group,FVC,FEV0.1 / FVC,PEF and MMEF decreased in the 3-month group and the 6-month group(P < 0.05).3.In the control group,the surface of the lung was smooth and soft,pink and elastic.Rats in the coal dust group were seen with black spots on the surface of the lungs;white bumps and plaques were seen on the lung surface of rats in the coal-silica dust group;obvious white bulges and plaques were seen on the lung surface of rats in the silica dust group.HE staining results showed that there was coal macule in the alveolar cavity of the coal dust group at 1 month and 3 months,there was observed with coal macule and coal dust fiber plaque at 6 month.In the coal-silica group,the alveolar septum was thickened and coal macule was observed at 1 month and 3 months.Coal macule,coal dust fiber plaque and coal-silicon nodule were observed at 6 months.A small amount of fibrous aggregation was observed in the silica dust group at 1 month;patchy fibrosis at 3 months;extensive fibrosis was observed at 6 months.Masson staining results showed that the alveolar structure was clear,the morphological structure was normal,and there was a very small amount of blue collagen fibers in the control group at different time points.The morphology and structure of the lung tissue in each group were partially destroyed in the 1 and 3 months,and the blue collagen fibers increased.In the 6-month group,the morphological structure of each group was significantly destroyed,and a large number of blue collagen fibers were deposited.4.Compared with the control group,the content of IL-6 in the 1-month group,the coal-silica dust group and the silica dust group increased(P < 0.05).Compared with the control group,the content of IL-6 in the 3-month group and in the 6-month group increased(P < 0.05).In the coal dust group,the content of IL-6 in the 6-month group was higher than that of the 1-month group and the 3-month group(P < 0.05).In the coal-silica dust group and the silica dust group,compared with the 1-month group,the content of IL-6 in the 3-month group and the 6-month group increased(P < 0.05).5.In the 1-month group,compared with the control group,the relative expression of let-7e in coal-silica dust group and silica dust group decreased(P< 0.05).Compared with the control group,the relative expression of let-7e in the 3-month group and 6-month group,the relative expression of let-7e in each dust exposed group decreased(P< 0.05).In the coal dust group,coal-silica dust group and silica dust group,compared with the 1-month group,the relative expression of let-7e in the 3-month group and the6-month group decreased(P < 0.05).6.In the 1-month group,compared with the control group,the expression of pMK2 protein in each dust group increased(P < 0.05);compared with the control group,the expression of NF-κB p65 and Lin28 protein in the silica dust group increased(P <0.05).In the 3-month group,the expression of p-MK2 protein in each dust exposed group was higher than that of the control group(P < 0.05).Compared with the control group,the expression of NF-κB p65 and Lin28 protein in the coal-silica dust group and the silica dust group increased(P < 0.05).Compared with the control group,the expression of p-MK2,NF-κB p65 and Lin28 protein in the 6-month group and the dust exposed groups increased(P < 0.05).In the coal dust group,there was no significant difference in the expression of NF-κB p65 between each month(P > 0.05).Compared with the 1-month group,the expression of p-MK2 protein in the 6-month group was increased(P < 0.05).Compared with the 1-month group,the expression of Lin28 protein in the 3-month group and the 6-month group increased(P < 0.05).In the coalsilica dust group,compared with the 1-month group,the expression of p-MK2 and Lin28 protein in the 6-month group increased(P < 0.05);compared with the 1-month group,the NF-κB p65 in the 3-month group and the 6-month group increased(P < 0.05).In the silica dust group,compared with the 1-month group,the expression of p-MK2,NF-κB p65 and Lin28 protein in the 3-month group and the 6-month group increased(P < 0.05).Conclusions:Different types of coal mine dust can increase the expression of MK2,activate NF-κB to induce Lin28 expression,inhibit let-7e production,increase IL-6 content,induce inflammation and the development of intrapulmonary fibrosis and coal workers’ pneumoconiosis in rats. |
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