Curcumin protects against inflammation and lung injury in rats with acute pulmonary embolism with the involvement of microRNA-21/PTEN/NF-κB axis.

This study was intended to investigate the effect of Curcumin on acute pulmonary embolism (APE) via microRNA-21 (miR-21)/PTEN/NF-κB axis. APE model was induced on rats and administrated with Curcumin. Western blot analysis and RT-qPCR manifested the downregulation of Sp1, miR-21 and NF-κB, but the upregulation of PTEN in Curcumin-treated APE rats. Blood gas analysis, ELISA, and weighing of wet weight/dry weight (W/D) ratio indicated that Curcumin diminished mPAP and RVSP levels, W/D ratio, thrombus volume, and inflammatory factors in the lungs of APE rats. Further mechanical analysis was conducted by dual-luciferase reporter assays and ChIP assay, which showed that Sp1 increased miR-21 expression by binding to the miR-21 promoter, and that PTEN was targeted by miR-21. The APE rats were injected with adenovirus to evaluate the effect of Sp1, miR-21, or PTEN on lung injury and inflammation. It was observed that downregulation of miR-21 or Sp1, or upregulation of PTEN diminished mPAP and RVSP levels, W/D ratio, thrombus volume, and inflammatory factors in the lungs of APE rats. In summary, Curcumin decreased miR-21 expression by downregulating Sp1 to upregulate PTEN and to impair the NF-κB signaling pathway, thus suppressing lung injury and inflammation in APE rats.