TY - JOUR AB - Acute lung injury (ALI) is a common clinical emergency and all‑trans retinoic acid (ATRA) can alleviate organ injury. Therefore, the present study investigated the role of ATRA in ALI. Lipopolysaccharide (LPS)‑induced ALI rats were treated with ATRA and the arterial partial pressure of oxygen (PaO2), lung wet/dry weight (W/D) ratio and protein content in the bronchial alveolar lavage fluid (BALF) were measured to evaluate the effect of ATRA on ALI rats. Alveolar macrophages were isolated from the BALF. The phagocytic function of macrophages was detected using the chicken erythrocyte phagocytosis method and flow cytometry. The viability of macrophages was measured using a Cell Counting Kit‑8 assay, and apoptosis was analyzed using a TUNEL assay and flow cytometry. The expression levels of Toll‑like receptor 4 (TLR4) and cluster of differentiation (CD)14 on the macrophage membrane were detected by immunofluorescence staining. The protein levels of TLR4, CD14, phosphorylated (p)‑65, p65, p‑IκBα and IκBα were analyzed using western blotting. The concentrations of IL‑6, IL‑1β and macrophage inflammatory protein‑2 in the plasma of rats were detected by ELISA. Macrophages were treated with IAXO‑102 (TLR4 inhibitor) to verify the involvement of CD14/TLR4 in the effect of ATRA on ALI. ATRA provided protection against LPS‑induced ALI, as evidenced by the increased PaO2 and reduced lung W/D ratio and protein content in the BALF. ATRA enhanced macrophage phagocytosis and viability and reduced apoptosis and inflammation in ALI rats. Mechanically, ATRA inhibited CD14 and TLR4 expression and NF‑κB pathway activation. ATRA enhanced macrophage phagocytosis and reduced inflammation by inhibiting the CD14/TLR4‑NF‑κB pathway in LPS‑induced ALI. In summary, ATRA inactivated the NF‑κB pathway by inhibiting the expression of CD14/TLR4 receptor in the alveolar macrophages of rats, thus enhancing the phagocytic function of macrophages in ALI rats, improving the activity of macrophages, inhibiting apoptosis, reducing the levels of inflammatory factors, and consequently playing a protective role in ALI model rats. This study may offer novel insights for the clinical management of ALI. AD - Department of Respiratory and Critical Care Medicine, Shanxi Provincial People's Hospital, Taiyuan, Shanxi 030012, P.R. China Department of Neurology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China Department of Cardiology, Taiyuan Central Hospital, Taiyuan, Shanxi 030009, P.R. China Department of Gynecology, Shanxi Provincial People's Hospital, Taiyuan, Shanxi 030012, P.R. China AU - Li,Shuangxue AU - Lei,Yuansheng AU - Lei,Jieyun AU - Li,Hui DA - 2021/12/01 DO - 10.3892/mmr.2021.12508 IS - 6 JO - Mol Med Rep KW - acute lung injury all‑trans retinoic acid cluster of differentiation 14 Toll‑like receptor 4 macrophage phagocytosis inflammation PY - 2021 SN - 1791-2997 1791-3004 SP - 868 ST - All‑trans retinoic acid promotes macrophage phagocytosis and decreases inflammation via inhibiting CD14/TLR4 in acute lung injury T2 - Molecular Medicine Reports TI - All‑trans retinoic acid promotes macrophage phagocytosis and decreases inflammation via inhibiting CD14/TLR4 in acute lung injury UR - https://doi.org/10.3892/mmr.2021.12508 VL - 24 ER -