Atractylenolide III Ameliorated Autophagy Dysfunction via EpidermalGrowth Factor Receptor-Mammalian Target of Rapamycin Signals and Alleviated Silicosis Fibrosis in Mice

Atractylenolide III (ATL-III) is a major active constituent of the natural plant Atractylodes rhizome. Our previous study has shown that ATL-III may alleviate alveolar macrophage apoptosis via the inhibition of the mammalian target of rapamycin (mTOR)-mediated autophagy of human silicosis. Therefore, we aimed to further explore the function of ATL-III in autophagy, apoptosis, and pulmonary fibrosis by establishing the ATL-III-intervened silicosis mouse model in this study. Meanwhile, we sought and then verified potential autophagy-related signaling pathways by matching differentially expressed genes (attained by RNA sequencing) and the autophagy database. In this study, RNA-sequencing results implied that the epidermal growth factor receptor, the crucial upstream activator of mTOR, was seen as a potential autophagy-regulatory molecule in the ATL-IIIeintervened silicosis mouse model. The finding of this study was that ATL-III might improve the disorder of autophagic degradation via the activation of epidermal growth factor receptor-mTOR signals in the pulmonary tissue of the silicosis mouse model. ATL-III also alleviated cell apoptosis and silicotic fibrosis. Overall, we supposed that ATL-III might be a potential protective medicine, which had a regulatory effect on autophagy, for the intervention of silicotic fibrosis. In the future, the therapeutic drugs for silicosis should be further focused on the development and application of such natural autophagy agents. Overall design: Male C57BL/6J mice (6 to 8 weeks old, 20 to 25g), were housed in an air-conditioned room under light-controlled conditions (twelve-hour light/twelve-hour dark cycle) with standard laboratory food and water ad libitum. A total of 60 mice were randomly divided into 3 groups as follows (n = 20 for every group): the Ctrl group, which was instilled intratracheally with 50 mL of saline; the Silica group, which was instilled intratracheally with 50 mL of saline containing 5 mg of silica; and the Silica þ ATL-III group, which was injected intraperitoneally with 0.2 mL of saline containing 30 mg/kg/d of ATL-III on the basis of the Silica group.. Mice were executed with pentobarbital sodium anesthesia on the 28th day after instillation, and lung tissues were extracted for RNA sequencing.