Pneumoconiosis is a widespread occupational disease in China at present. As a type of lung diseases, its pathological damage is mainly irreversible fibrotic changes in the lungs. Several studies have shown that the occurrence and development of lung diseases such as coal workers' pneumoconiosis are closely related to intestinal flora.

To observe intestinal flora of coal workers' pneumoconiosis patients based on the results of 16SrDNA high-throughput sequencing and evaluate the changes of intestinal flora after treatment with tetrandrine tablets.

A total of 80 patients with coal workers' pneumoconiosis attending the outpatient clinic of the Department of Occupational Diseases of the Emergency General Hospital from April to July 2022 were enrolled. All patients were treated with tetrandrine tablets for 4 weeks, with group A before the treatment of tetrandrine tablets and group B after the treatment. In the same period, 24 healthy controls (group C) were set up. Stool samples were collected before and after the treatment. Using 16SrDNA high-throughput sequencing, gene V3-V4 sequencing technology, and bioinformatic analysis platform, we evaluated the intestinal flora after treatment by groups.

The dominant flora at the phylum level and genus level were the same across three groups. The relative abundances of phylum Bacteroidetes, Bifidobacterium, Bacteroides, and Facealibacterium in groups B and C were higher than those in group A, and the relative abundances of phy-lum Actinobacteria, genus Blautia, and genus Romboutsia in groups B and C were lower than those in group A (P＜0.05). The relative abundances of genus Clostridium, genus Megamonas, and genus Lactobacillus in group C was lower than that in groups A and B (P＜0.05). The alpha diversity analysis showed that the Chao1 index was higher in group A than in group C (P＜0.01). Compared with group A, the Shannon index was higher in group B, and the increases of Simpson index were all statistically significant in stage I patients (P＜0.05), but the differences in Chao1 index were not statistically significant (P＞0.05). The differences in the values of Chao1 index, Shannon index, and Simpson index in stage Ⅱ and stage III patients were not statistically significant (P＞0.05). The beta diversity analysis showed that the difference in flora structure between group A and group C was statistically significant (P＜0.05); the differences in flora structure before and after treatment in the same stage patients were statistically significant (P＜0.05). The partial least squares discriminant analysis (PLS-DA) showed that there were significant differences between group A and group C, and between group A and group B. The LEfSe analysis showed that the significant markers contributing to the differences were basically the same in stage I, stage Ⅱ, and stage Ⅲ after treatment, which were mainly phylum Bacteroidetes and its subordinate groups, class Negativicutes, or-der Selenomonas, and genus Facealibacterium.

There are differences in the distribution of flora between coal workers' pneumoconiosis patients and healthy individuals, and the structure and relative abundance of intestinal flora are changed and the number of beneficial flora is increased after treatment with tetrandrine tablets.