Ginsenoside Rb3 alleviates smoke‐induced lung injury via the H19/miR‐29b‐3p/HGMB1/TLR4 signalling pathway

The over‐activation of inflammation is involved in the pathogenesis of smoke‐induced lung injury (SILI), while Rb3 treatment may alleviate smoke‐induced lung injury by down‐regulating the expression of H19, a regulator of miR‐29b expression. Moreover, HMGB1 is an important mediator of inflammation. Therefore, in this study, we set up an animal model of SILI and treated it with Rb3 to study the effect of Rb3 on the treatment of SILI and the involvement of H19/miR‐29b/HMGB1/TLR4 signalling. SILI mice treated with Rb3 before H&E staining and TUNEL assay were conducted to observe the pathological damages and status of apoptosis in each group. Real‐time PCR, Western blot, computational analysis and luciferase assays were utilized to establish the signalling pathway involved in the pathogenesis of SILI and the action of Rb3 treatment. Rb3 treatment alleviated pathological changes in the lungs while decreasing the levels of W/D ratio and cell apoptotic index. H19 was validated to sponge miR‐29b‐3p, while HMGB1 mRNA was validated to be a target gene of miR‐29b‐3. As a result, a signalling pathway of H19/miR‐29b‐3p/HMGB1 was established. Cell viability was evidently reduced after 72 hours of treatment with CSE, but the treatment of Rb3 elevated the expression of H19 and HMBG1 in the presence of CSE. Also, CSE‐induced inhibition of miR‐29b‐3p expression was restored by Rb3. The findings of this study collectively demonstrated that Rb3 exhibited its therapeutic effect during the treatment of SILI via modulating the H19/miR‐29b‐3p/HMBG1 signalling pathway.