Changes Of Lipid Metabolism In Alveolar Macrophages From Silicosis Patients

Objectives To investige the changes of lipid metabolism in alveolar macrophages of patients with silicosis and analyze its role in the development of silicosis so as to further elucidate the mechanism of silicosis and provide new ideas for silicosis treatment.Methods Object selection: the objects of the study were selected from silicosis patients of the Beidaihe Chinese coal miners sanatorium who treated with the lung lavage surgery at first time and these people's career were mainly pioneering,digging,crushing,drilling,stone processing and so on.The stage of silicosis was diagnosed by pneumoconiosis diagnostic expert group according to GBZ-70-2009 "pneumoconiosis diagnostic criteria".Among them,18 cases were silicosis stage I,17 cases were silicosis stage II and 24 cases were silicosis stage III,all patients were male.The control group had 8 cases including 3cases of aspiration,5 cases of silicosis observation.In addition,12 healthy adult males were taken as the serum control group.The subjects should exclude patients with active pulmonary tuberculosis,pneumonia,pulmonary heart disease and other lung diseases,infectious diseases and some silicosis patients with fibrosis in other parts,in the meantime excluding liver dysfunction and hyperlipidemia patients.There was no significant difference in the age and body mass index(BMI)among these groups in different phase.The samples collection: the serum samples were collected in 1.5ml EP tube by centrifugation.Alveolar macrophages were extracted from alveolar lavage fluid and supernatant was collected at the sametime.All samples were stored at-80?.Methods:HE and oil red O staining were used to take morphological observation.The ultrastructure of macrophages was observed by transmission electron microscopy.The lipid in alveolar macrophages and alveolar lavage fluid was isolated and analyzed qualitatively by thin layer chromatography(TLC).Double antibody sandwich method(ELISA)was used to measure levels of TGF-?1 and CTGF in alveolar macrophages,alveolar lavage fluid and serum.The levels of ox-LDL in alveolar macrophages,alveolar lavage fluid were measured by ELISA.Cholesterol,triglyceride,phospholipid concentration in alveolar macrophages and alveolar lavage fluid were measured by colorimetric method.Results 1 Compared with control group,HE staining revealed a large number of vacuoles in alveolar macrophages of silicosis groups,phagocytic particles in the cytoplasm and it is the most obvious in phase III.2 Compared with control group,oil red O staining found that orange red fat droplets appeared in alveolar macrophages and a lot of phagocytic particles could be seen in cytoplasm of silicosis groups,and it is the most obvious in phase III.It was confirmed that lipid was present in alveolar macrophages.3 In silicosis groups,the observation by electron microscopy revealed alveolar macrophages pseudopodia rupture,disappeared,fine nucleus chromatin concentrated edge set,secondary lysosomal increase,mitochondrial swelling,condensation,vacuoles,cytoplasm in the bubble phenomenon,and there were the most obvious in II and III stage silicosis patients.4 Thin layer chromatography showed that lipids in alveolar macrophages and alveolar lavage fluid contain cholesterol,triglycerides and phospholipids.It was found that the level of cholesterol in AM and BALF were increased in AMs and BALF among the four groups,and the cholesterol level in stage III was significantly higher than that of control group,stage Iand stage IIof silicosis group(P<0.05).Phospholipid and ox-LDL levels in AM wereincreased along with the silicosis stage progression,whereas,ox-LDL level presented a declining trend in the BALF and the differences between any two means pairwise comparison had statistical significance(P<0.05).Differences of phospholipid level in any two groups had statistical significance(P<0.05).In detail,phospholipid level in stage I/IIand III silicosis group was significantly higher than that of control group(P<0.05),stage II silicosis group's phospholipid level was lower than that of stage I,phospholipid level in stage III group was significantly higher than that of stage Iand II.The difference of triglyceride level in BALF groups had no statistically significant(P>0.05).6 The level of CTGF and TGF-? in serum increased with the progress of silicosis,and the difference was statistically significant(P<0.05).In addition,serum CTGF level was positively correlated with TGF-?(P<0.05).The levels of TGF-? and CTGF in alveolar macrophages were increased first and then decreased and significantly lower than those in silicosis groups(P<0.05).The levels of TGF-? and CTGF were reached the maximum value at stage I and stage II respectively.The difference of TGF-? and CTGF level in BALF groups had not statistically significant(P>0.05).7 The level of cholesterol,triglyceride,phospholipid,oxLDL in AM were positively correlated with CTGF and TGF-? inserum(P<0.05).The level of cholesterol,phospholipid in BALF were positively correlated with CTGF and TGF-?inserum(P<0.05).The level of ox-LDL in BALF werenegative correlation with CTGF and TGF-? inserum(P<0.05).Triglyceride level in BALF had no correlation with CTGF and TGF-? inserum(P>0.05).Conclusions 1Alveolar macrophages in silicosis patients transform into foam cells and exist a phenomenon of lipid accumulation.2 With the development of silicosis,CTGF and TGF-? levels in serum of silicosis patients were on the rise.The levels of TGF-? and CTGF in alveolar macrophages were increased first and then decreased and reached the maximum value at stage I and stage II respectively.3 In the development of fibrosis,alveolar macrophages exist lipid metabolism imbalance phenomenon.There are amount of lipid accumulation in alveolar macrophages,and the amount of accumulation was increased with deterioration of the degree of fibrosis,the mechanism may be associated with occurrence of the bubble in alveolar macrophage.