The study of smoking impact on autophagy in alveolar macrophages of human silicosis

Objective: To investigate the effect of smoking on autophagy in alveolar macrophages (AMs) of silicosis patients. Methods: In December 2019, a random sampling method was used to select 42 male patients with silicosis (19 cases of stage II and 23 cases of stage III) who were treated with large volume whole lung lavage from August to December 2017 in the Beidaihe sanatorium. According to the different smoking index of the study subjects (smoking index=smoking cigarette consumptions per day×years of smoking) , we divided them into high (Smoking index>400) , medium (200≤smoking index≤400) , low (smoking index <200) and non-smoking group. The levels of autophagy related proteins LC3, Beclin1, p62 and apoptosis related protein Cleaved Caspase-3 were detected by Western blot. The effects of smoking on autophagy activity of AMs in silicosis were analyzed. Results: The ratio of autophagy related protein LC3 II/LC3 I, the expression of Beclin1, p62, and apoptosis related protein Cleaved Caspase-3 in the high smoking group were significantly higher than that of the middle, low smoking group and the non-smoking group (P<0.05) . Conclusion: Smoking can aggravate the dysfunction of autophagic degradation in silicosis patients' AMs, which may accelerate the progress of silicosis through increasing apoptosis in AMs.