TGFB1 and pulmonary fibrosis: Therefore, although in the present study we attempted to investigate the effect of IMRC-EVs on early pulmonary fibrosis and also preliminarily evaluated the effect of IMRC-EVs on the TGF-β activation pathway at the in vitro level, whether EVs can have any beneficial effect in patients with pulmonary fibrosis still needs to be carefully investigated, and the effective EVs administration time window and the related molecular markers need to be further explored.