Abstract:

Objective

To analyze the effect of interleukin-10（IL-10） on the balance of T helper cell 17 （Th17）/regulatory T cell （Treg） and its effect on mice with transfusion-related acute lung injury （TRALI）.

Methods

Sixty mice were divided into a control group，a transfusion-related acute lung injury （TRALI）group，an interleukin-10 low-dose （IL-10-L） group，and an interleukin-10 high-dose （IL-10-H） group，with 15 mice in each group. Calculate the arterial partial pressure of oxygen （PaO₂），the partial pressure of carbon dioxide （PaCO₂），the oxygenation index （OI），and the wet/dry weight ratio（W/D） of lung tissues. Use the enzyme-linked immunosorbent assay （ELISA） to detect the levels of inflammatory factors in bronchoalveolar lavage fluid （BALF），including interleukin-6 （IL-6），interferon-γ （INF-γ），tumor necrosis factor-α （TNF-α），and interleukin-17A （IL-17A）. Detect the total number of cells and the proportion of neutrophils in BALF.Measure the activity of myeloperoxidase （MPO）. Use flow cytometry to detect the number of helper T cell 17（Th17） and regulatory T cell （Treg） cells in peripheral blood. Use reverse transcription-quantitative polymerase chain reaction （RT-qPCR） and Western blotting （WB） to detect the mRNA and protein levels of Th17/Treg cell-related markers in lung tissues，including IL-17A，retinoic acid-related orphan receptor γt（RORγt），forkhead box protein P3 （Foxp3），glucocorticoid-induced tumor necrosis factor receptor-related protein （GITR），and cytotoxic T lymphocyte-associated protein 4 （CTLA-4）.

Results

Compared with the control group，the levels of PaO₂ and OI in the TRALI group decreased （t=5.921，8.216，P＜0.001），and the levels of PaCO₂，the （W/D） of lung tissues，and the activity of MPO increased （t=10.257，7.843，3.987，P＜0.001）. Except for the control group，the lung tissues of the other groups were damaged to varying degrees.Red blood cells and inflammatory cells in the alveolar septa and alveolar cavities showed varying degrees of thickening and infiltration. The proportion of Th17 cells in peripheral blood and the Th17/Treg ratio increased（t=9.836，7.125，P＜0.05），and the proportion of Treg cells decreased （t=6.254，P＜0.05）. The mRNA and protein levels of IL-17A and RORγt in lung tissues increased （t=4.850，8.966，6.401，3.248，P＜0.05），while the mRNA and protein levels of Foxp3，GITR，and CTLA-4 decreased （t=3.567，10.190，7.632，4.610，8.789，t=2.436，P＜0.05）. The levels of IL-6，INF-γ，TNF-α，IL-17A，the total number of cells，and the percentage of neutrophils in BALF increased （t=7.802，2.331，6.208，7.127，3.709，7.540，P＜0.05）.Compared with the TRALI group，the levels of PaO₂ and OI in the IL-10-L group and the IL-10-H group increased （P ＜0.001），and the levels of PaCO₂，the （W/D） of lung tissues，and the activity of MPO decreased （P ＜0.001）. Slight structural damage could be seen in the lung tissues，accompanied by less bleeding and inflammatory reactions. The proportion of Th17 cells in peripheral blood and the Th17/Treg ratio decreased，and the proportion of Treg cells increased （P＜0.05）. The mRNA and protein levels of IL-17A and RORγt in lung tissues decreased，while the mRNA and protein levels of Foxp3，GITR，and CTLA-4 increased（P＜0.05）. The levels of IL-6，INF-γ，TNF-α，IL-17A，the total number of cells，and the percentage of neutrophils in BALF decreased （P＜0.05）.

Conclusion

IL-10 modulates the Th17/Treg cell balance，thereby mitigating TRALI in murine models，highlighting its potential as a therapeutic strategy.

Key words: Mouse, Interleukin-10, Th17/Treg cells balance, Transfusion related acute lung injury