Hesperidin alleviates pulmonary fibrosis by regulating EI24-mediated autophagy

Etoposide-induced protein 2.4 (EI24), an essential component of autophagy, is lowly expressed in pulmonary fibrosis. Hesperidin (Hes), a flavonoid, can regulate autophagy in various diseases. However, whether Hes can inhibit pulmonary fibrosis by mechanically regulating EI24-mediated autophagy has not been uncovered. RLE-6TN cells were treated with transforming growth factor β1 (TGF-β1) and rats were injected with bleomycin (BLM) to construct the pulmonary fibrosis model. The effect of Hes on pulmonary fibrosis was evaluated by cell counting kit-8, immunofluorescence, hematoxylin and eosin, masson trichome staining and western blotting. Hes reduced cell viability of TGF-β1-induced RLE-6TN cells. Administration of Hes restored the decrease in autophagy marker levels in TGF-β1-induced RLE-6TN cells. Hes inhibited the transcriptional and translational levels of α-SMA, collagen I and fibronectin that were increased by TGF-β1 in RLE-6TN cells. Mechanically, Hes restored EI24 expression, and EI24 knockdown reversed the effect of Hes on the expressions of autophagy and fibrosis-related proteins. Additionally, Hes enhanced autophagy and fibrosis markers, which were worsened by EI24 knockdown in BLM-induced rats. Hes activated autophagy by upregulating EI24, which improved pulmonary fibrosis both <i>in vitro</i> and <i>in vivo</i>. Hes activated TGF-β1-induced autophagy in RLE-6TN cells.Hes inhibited TGF-β1-induced fibrosis in RLE-6TN cells.Hes suppressed fibrosis by regulating EI24-mediated autophagy in TGF-β1-induced RLE-6TN cells.Hes attenuated BLM-induced fibrosis of rat lung tissue.Hes activated autophagy in BLM-induced fibrosis <i>in vivo.</i> Hes activated TGF-β1-induced autophagy in RLE-6TN cells. Hes inhibited TGF-β1-induced fibrosis in RLE-6TN cells. Hes suppressed fibrosis by regulating EI24-mediated autophagy in TGF-β1-induced RLE-6TN cells. Hes attenuated BLM-induced fibrosis of rat lung tissue. Hes activated autophagy in BLM-induced fibrosis <i>in vivo.</i> In this study, we looked at how a natural compound called Hesperidin might help fight a common type of lung disease called pulmonary fibrosis. This disease can harm lung tissue structures and may cause death. We treated rats with a substance that causes pulmonary fibrosis, then gave some of them Hesperidin to see if it would help. We watched how their weight changed, how much the lung structure damaged and how many lung fibroses they had. Our results were promising: the rats treated with Hesperidin were healthier than those that weren’t. They had less lung weight, had more normal lung tissue structure, and showed fewer signs of fibrosis. This suggests that Hesperidin could be a new way to protect against pulmonary fibrosis.