To investigate the effects of acetylcholine receptor(AChR) on T-cell subpopulations CD3⁺, CD25⁺ Foxp3⁺ T cells, CD11b, and inflammatory factors IL-1β, TNF-α in acute respiratory distress syndrome (ARDS) mice.

Fifty (6 weeks) healthy and clean male balb/C mice were randomly divided into normal group (N group), normal saline control group (NS group), ARDS group (A group), ARDS+ transection of the vagus nerve on both sides of the neck(D group), ARDS+ group given AChR after transection of the vagus nerve on both sides of the neck (A+ J group), 10 mice in each group were fed normally. HE staining was used to observe the right lung structure of mice in each group, and flow cytometry was used to detect the percentages of CD3⁺, CD11b, CD25⁺ Foxp3⁺ T cells in the bronchoalveolar lavage fluid of mice. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of IL-1β mRNA and TNF-α mRNA in the left lung tissue.

The HE staining of the right lung in the N group and NS group of mice showed normal structure, but that of the A and D groups of mice showed a large amount of inflammatory cell infiltration in the interstitium, significant thickening of the alveolar walls, and obvious destruction of the alveolar structure with alveolar fusion. The alveolar structure of mice in A+ J group was relatively complete with a little damage and alveolar cavities. The percentages of CD11b, CD3⁺, and CD25⁺ Foxp3⁺ T cells in the bronchoalveolar lavage fluid of mice in groups A and D were higher than those in the other 3 groups. In the A+ J group, the percentages of CD11b (10.77±2.41), CD3⁺ (5.94±0.27), and CD25⁺ Foxp3⁺ T cells (5.00±1.15) were statistically significantly different from the D group (15.32±1.56, 9.78±0.88, 9.84±1.11) and the A group (13.49±2.06, 8.55±1.07, 8.98±0.91) (t=3.04, 2.61, 2.87, 3.87, 2.54, 2.53, all P<0.05). In the A+ J group of mice, the expressions of IL-1β mRNA (198.98±54.05) and TNF-α mRNA (52.41±12.26) in the left lung were significantly different from the A group (384.26±69.03, 96.84±20.02) and the D group (397.26±64.31, 99.45±18.34) (t=94.42, 99.54, 91.32, 98.57, P<0.05).

The activation of the cholinergic anti-inflammatory pathway by acetylcholine receptors not only inhibits the release of T lymphocytes in lung tissue, but also suppresses the expressions of IL-1β mRNA and TNF-α mRNA in lung tissue, as well as the release of CD11b, thus inhibiting the inflammatory response of ARDS and alleviating the pathological changes in ARDS.