The Effect Of Ac-SDKP On Inhibition Of Silicosis Fibrosis Through The Regulation Of Macrophage Activation

Objectives To investigate the regulation of N-acetyl-seryl-asyl-lysyl-proline(N-acetylseryl-aspartyl-lysyl-proline,Ac-SDKP)on macrophage activation and phenotypic changes in silicosis fibrosis.Methods 1.The model of silicosis rat was constructed using HPOE-ED8050 dynamic dusting system.Seventy SPF Wistar male rats,10 in each group,were randomly divided into groups.1)Observation of the activation of macrophages during the development of silicosis fibrosis.The experiment was divided into(1)Silicosis model 4 weeks and 16 weeks group: the animals were killed by dusting to 4 weeks(Sicosis 4 w,S4)and 16 weeks(Sicosis 16 w,S16);(2)Control group: animals were fed to 4 weeks(Control 4 w,C4W)and 16 weeks(Control 16 w,C16)respectively;2)Study of the Ac-SDKP regulation on macrophage activation.The experiment was divided into(1)Control group: conventional feeding until 16 weeks,a small amount of sustained-release capsules containing physiological saline embedded in the abdominal cavity,and feeding until 24 weeks of sacrifice(Control 24 w,C24W);(2)Dust group: when the Si O2 dust was exposed to 16 weeks,physiological saline micro-sustained-release capsules were put in the abdominal cavity of rats,the animals were killed until to 24 weeks(Sicosis 24 w,S24);(3)Ac-SDKP intervention group: when the Si O2 dust was exposed to 16 weeks,physiological saline micro-sustained-release capsules containing Ac-SDKP(800μg / kg /d)were put in in the abdominal cavity of rats,the animals were killed until to 24 weeks(AcSDKP).2.Culture mouse-derived cell line mouse mononuclear macrophages(RAW264.7 cells)was induced by silicon dioxide(Si O2).The experiments were divided into control group(control,C),Si O2 induction group(silicosis,S),Ac-SDKP intervention group(AcSDKP+silicosis,Ac+S).Immunohistochemical staining was used to detect the localized expression of iNOS and Arg-1 in the lung tissue of patients with coal silicosis and rat model,and immunofluorescence staining was used to detect the localized expression of iNOS and Arg-1.Western blot methoed was used to detect the expression changes of type I collagen(COLI),α-smooth muscle actin(α-SMA),type I macrophage marker(inducible nitric oxide synthase,iNOS),and type II macrophages marker(Arginase-1,Arg-1)and monocyte chemoattractant protein-1(MCP-1)in the lung tissue of rats and RAW264.7 cells.Results 1.Observation of autopsy specimens from human coal silicosis showed that the development of coal silicosis appeard a dynamic evolution process,inclued macrophage alveolitis,cellular silicon nodules,cell fibrous silicon nodules and fibrous silicon nodules.2.Immunohistochemical staining results showed that there were a large amount of coal dust deposits in the cellular and fibrous silicon nodules ofhuman coal silicosis tissue specimens,and the distribution and expression of CD68 and Arg-1positive cells in these nodules were seen respectively.In the controlgroup of rat lung tissue,iNOS and Arg-1 positive expression cells were occasionallyed seen.In the 4 week group of rats exposed to dust,many iNOS positive cellsand a smaller amount of Arg-1 positive cells were expressed in the lung tissue ofthe rats.In the 16 week group of rat lung tissues,there were more Arg-1 positive cells and a small number of iNOS positive cells were expressed inthe silicon nodules.The distribution and expression of iNOS positive cells were seen in the alveolar cavity around the nodules;3.Immunofluorescence results showed that there were more iNOS labeled macrophages in the 4 week group of silicosis model,andmore Arg-1-labeled macrophages in the lung tissue of the 16 week silicosis model.Western blot results showed that compared with the normal control group,the expression of iNOS and Arg-1 protein in the lung tissue of the 4 week silicosis model group and 16 week silicosis model group of were up-regulated.Compared with the 4 week silicosis model group,the expression of iNOS was decreased and the expression of Arg-1 was increased in the 16 week silicosis model group.4.Compared with the 24 week silicosis model group,the expressions of MCP-1,iNOS,Arg-1,α-SMA and COLI were all down-regulated after Ac-SDKP intervention,the difference was statistically significant(P<0.05).5.Compared with the control group,iNOS,Arg-1 and MCP-1 expression levels were up-regulated in the RAW264.7cells were induced by Si O2;Compared with the Si O2 induced group,the expressionlevels of iNOS,Arg-1,and MCP-1 in the Ac-SDKP intervention group were down-regulated,the difference was statistically significant(P<0.05).Conclusions 1.Macrophage activation and change of different phenotypes are involved in the formation of silicosis fibrosis.2.Ac-SDKP is possible to exert its role in inhibiting silicosis fibrosis by regulating the activation of macrophages.Figure 10;Table 5;Reference 151...