ObjectiveTo investigate the effects of Maxing Kugan decoction （MKD） on inflammatory response and apoptosis in rats with oleic acid （OA）-induced acute lung injury （ALI） and explore its mechanism of action. MethodsSixty Sprague-Dawley （SD） rats were randomly assigned into six groups： a control group， a model group， a dexamethasone-treated group （2 mg·kg^-1）， and three MKD-treated groups at low， medium， and high doses （3.1， 6.2，12.4 g·kg^-1）. Each group was administered either an equivalent volume of normal saline or the corresponding concentration of MKD by gavage for seven consecutive days. The model group and each administration group were used to establish the ALI model by tail vein injection of OA （0.2 mL·kg^-1）. Twelve hours after modeling， blood gas analyses were conducted， and the wet-to-dry （W/D） weight ratio of lung tissue was measured for each group. Additionally， enzyme-linked immunosorbent assay （ELISA） was employed to quantify the levels of tumor necrosis factor-alpha （TNF-α）， interleukin-1β （IL-1β）， and interleukin-6 （IL-6） in the bronchoalveolar lavage fluid （BALF） of the rats. Cell damage and apoptosis in lung tissue were examined via hematoxylin-eosin （HE） staining and TdT-mediated dUTP-biotin nick end labeling （TUNEL） assays， and the results were subsequently scored. The expression levels of the p38 mitogen-activated protein kinase （p38 MAPK）/nuclear factor kappa-B （NF-κB） signaling pathway and apoptosis-related proteins and mRNAs were assessed using Western blot and real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. ResultsCompared with the control group， the model group exhibited a significant decrease in partial pressure of oxygen （PaO₂）， blood oxygen saturation （SaO₂）， and oxygenation index （PaO₂/FiO₂）， along with a marked increase in partial pressure of carbon dioxide （PaCO₂） and lung W/D ratio （P<0.01）. Additionally， levels of TNF-α， IL-6， and IL-1β in BALF were significantly elevated （P<0.01）. Histopathological analysis of lung tissue showed significant inflammatory infiltration， tissue edema， alveolar septal thickening， and apoptosis of lung tissue. Pronounced increases were observed in the mRNA expression levels of p38 MAPK， NF-κB p65， inhibitor of NF-κB （IκBα）， B-cell lymphoma-2 associated x protein （Bax）， and Caspases-3， as well as the protein expression levels of p-p38 MAPK， p-NF-κB p65， p-IκBα， Bax， Caspases-3， and cleaved Caspases-3， while the mRNA and protein expression of Bcl-2 was downregulated （P<0.01）. Compared with the model group， MKD significantly elevated PaO₂， SaO₂， and PaO₂/FiO₂ while reducing PaCO₂ and W/D ratio in rats （P<0.01）. It also greatly reduced TNF-α， IL-6， and IL-1β levels in BALF （P<0.01） and alleviated inflammatory infiltration， tissue edema， alveolar septal thickening， and apoptosis of lung tissue. Additionally， it downregulated the mRNA expression of p38 MAPK， NF-κB p65， IκBα， Bax， Caspases-3， as well as protein expression of p-p38 MAPK， p-NF-κB p65， p-IκBα， Bax， Caspases-3， and cleaved Caspases-3 in lung tissue （P<0.05， P<0.01）， while significantly upregulating mRNA and protein expression of Bcl-2 （P<0.01）. ConclusionMKD exerts a protective effect on OA-induced ALI rats， potentially through the regulation of the p38 MAPK/NF-κB signaling pathway to inhibit inflammation and apoptosis.

ObjectiveTo investigate the effects of Maxing Kugan decoction （MKD） on inflammatory response and apoptosis in rats with oleic acid （OA）-induced acute lung injury （ALI） and explore its mechanism of action. MethodsSixty Sprague-Dawley （SD） rats were randomly assigned into six groups： a control group， a model group， a dexamethasone-treated group （2 mg·kg^-1）， and three MKD-treated groups at low， medium， and high doses （3.1， 6.2，12.4 g·kg^-1）. Each group was administered either an equivalent volume of normal saline or the corresponding concentration of MKD by gavage for seven consecutive days. The model group and each administration group were used to establish the ALI model by tail vein injection of OA （0.2 mL·kg^-1）. Twelve hours after modeling， blood gas analyses were conducted， and the wet-to-dry （W/D） weight ratio of lung tissue was measured for each group. Additionally， enzyme-linked immunosorbent assay （ELISA） was employed to quantify the levels of tumor necrosis factor-alpha （TNF-α）， interleukin-1β （IL-1β）， and interleukin-6 （IL-6） in the bronchoalveolar lavage fluid （BALF） of the rats. Cell damage and apoptosis in lung tissue were examined via hematoxylin-eosin （HE） staining and TdT-mediated dUTP-biotin nick end labeling （TUNEL） assays， and the results were subsequently scored. The expression levels of the p38 mitogen-activated protein kinase （p38 MAPK）/nuclear factor kappa-B （NF-κB） signaling pathway and apoptosis-related proteins and mRNAs were assessed using Western blot and real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. ResultsCompared with the control group， the model group exhibited a significant decrease in partial pressure of oxygen （PaO₂）， blood oxygen saturation （SaO₂）， and oxygenation index （PaO₂/FiO₂）， along with a marked increase in partial pressure of carbon dioxide （PaCO₂） and lung W/D ratio （P<0.01）. Additionally， levels of TNF-α， IL-6， and IL-1β in BALF were significantly elevated （P<0.01）. Histopathological analysis of lung tissue showed significant inflammatory infiltration， tissue edema， alveolar septal thickening， and apoptosis of lung tissue. Pronounced increases were observed in the mRNA expression levels of p38 MAPK， NF-κB p65， inhibitor of NF-κB （IκBα）， B-cell lymphoma-2 associated x protein （Bax）， and Caspases-3， as well as the protein expression levels of p-p38 MAPK， p-NF-κB p65， p-IκBα， Bax， Caspases-3， and cleaved Caspases-3， while the mRNA and protein expression of Bcl-2 was downregulated （P<0.01）. Compared with the model group， MKD significantly elevated PaO₂， SaO₂， and PaO₂/FiO₂ while reducing PaCO₂ and W/D ratio in rats （P<0.01）. It also greatly reduced TNF-α， IL-6， and IL-1β levels in BALF （P<0.01） and alleviated inflammatory infiltration， tissue edema， alveolar septal thickening， and apoptosis of lung tissue. Additionally， it downregulated the mRNA expression of p38 MAPK， NF-κB p65， IκBα， Bax， Caspases-3， as well as protein expression of p-p38 MAPK， p-NF-κB p65， p-IκBα， Bax， Caspases-3， and cleaved Caspases-3 in lung tissue （P<0.05， P<0.01）， while significantly upregulating mRNA and protein expression of Bcl-2 （P<0.01）. ConclusionMKD exerts a protective effect on OA-induced ALI rats， potentially through the regulation of the p38 MAPK/NF-κB signaling pathway to inhibit inflammation and apoptosis.