Correlation Between 1, 25-(OH)₂D₃ and Pulmonary Fibrosis Related Cytokines in Peripheral Blood of Pneumoconiosis Patients

Objective To measure the levels of 1, 25-dihydroxy vitamin D₃ 1, 25-(OH)₂D₃ and pulmonary fibrosis related cytokines in peripheral blood of pneumoconiosis patients, and assess the correlation between them.

Methods From April to May 2015, 43 male patients visiting an occupational disease prevention and treatment center affiliated to a mining corporation were selected as the pneumoconiosis group (28 cases diagnosed as stage Ⅰand 15 cases as stage Ⅱ). In the same period, 27 males without dust exposure history ordered health check services were selected as the control group. Their general information and fasting blood samples were collected. Electrochemiluminescence was used to detect 1, 25-(OH)₂D₃ level and ELISA was used to detect transforming growth factor β1 (TGF-β1), interleukin-4 (IL-4), and γ-interferon (INF-γ) levels. The differences between indicators were evaluated through one-way analysis of variance (ANOVA) followed by pair-wise comparison using Student-Newman-Keuls test. Pearson correlation analysis was also applied.

Results The 1, 25-(OH)₂D₃ level of the control group was (22.16±5.71) μg/L, that of the pneumoconiosis patients in stage Ⅰwas (13.11±4.01) μg/L, and that of the pneumoconiosis patients in stage Ⅱ was (9.96±3.18) μg/L; compared with the control group, the 1, 25-(OH)₂D₃ level of the pneumoconiosis patients was reduced with the advance of pneumoconiosis stage (P < 0.01). The TGF-β1 level of the control group was (25.59±6.12) μg/L, that of the pneumoconiosis group in stage Ⅰwas (39.20±6.32) μg/L, and that of pneumoconiosis group in stage Ⅱwas (50.90±5.97) μg/L; compared with the control group, the TGF-β1 level of the pneumoconiosis patients was elevated with the advance of pneumoconiosis stage (P < 0.01). The IL-4 level of the control group was (25.03±3.79) ng/L, that of the pneumoconiosis group in stage Ⅰwas (32.67±5.32) ng/L, and that of the pneumoconiosis group in stage Ⅱwas (37.52±5.71) ng/L; compared with the control group, the IL-4 level of the pneumoconiosis patients was elevated with the advance of pneumoconiosis stage (P < 0.01). The INF-γ level of the control group was (32.53±6.50) ng/L, that of pneumoconiosis group in stageⅠwas (16.64±4.06) ng/L, and that of the pneumoconiosis group in stageⅡwas (13.70±2.98) ng/L; compared with the control group, the INF-γ level of the pneumoconiosis patients was decreased (P < 0.01), but there was no significant difference between the pneumoconiosis patients in stageⅠand stage Ⅱ (P>0.05). The peripheral 1, 25-(OH)₂D₃ levels of the pneumoconiosis patients had a positive correlation with INF-γ levels (r=0.944, P < 0.05), while a negative correlation with TGF-β1 and IL-4 levels (r=-0.814, r=-0.937, both Ps < 0.05).

Conclusion The peripheral 1, 25-(OH)₂D₃ level of pneumoconiosis patients associates with the expression levels of pulmonary fibrosis related cytokines and might involve in the pathogenesis of pneumoconiosis.