Nintedanib ameliorates tracheal stenosis by activating HDAC2 and suppressing IL-8 and VEGF in rabbit

Abstract

Acquired tracheal stenosis is a common disease occurring after endotracheal intubation or tracheotomy. Currently, surgery is the main option to treat the stenosis. This study investigated therapeutic effect and possible mechanism of nintedanib on tracheal stenosis. The rabbit models of tracheal stenosis were established and were administered with nintedanib and budesonide. The damage and repair of the tracheal tissue were determined using hematoxylin and eosin (HE) staining. The expression of histone deacetylase 2 (HDAC2), interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) was detected by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western Blot and immunofluorescence assay. The expression of collagens I and III was assayed immunohistochemically. Remarkable tracheal stenosis was observed after the trachea was brushed in the rabbit model. Compared with control, the stenosis was improved after nintedanib treatment. The mRNA of HDAC2 was increased and that of IL-8 and VEGF was decreased significantly in the tracheal tissue following nintedanib treatment. Western blot analysis showed that HDAC2 increased to the level similar to that of control while VEGF remained unchanged following nintedanib treatment. Budesonide treatment also resulted in increased HDAC2 expression and decreased IL-8 and VEGF expression. Immunofluorescence assays also showed an increased HDAC2 expression following nintedanib treatment. Collagens I and III decreased significantly after nintedanib treatment in the tracheal tissues of models. Therefore, it is concluded that nintedanib alleviates the acquired tracheal stenosis by activating HDAC2 expression and suppressing IL-8 and VEGF expression, and may offer new option to medical treatment for the disease.

Keywords: HDAC2; IL-8; Tracheal stenosis; VEGF; nintedanib.

Figure 1

Tracheal stenosis (A) and HE staining (B) of tracheal tissues from rabbits after tracheal brushing and nintedanib treatments 2 day after treatments. Arrows indicated inflammatory cells. * and # denote P < 0.01 vs control and model, respectively.

Figure 2

Relative mRNA level of HDAC2, IL-8 and VEGF in tracheal tissues from rabbits after tracheal brushing and nintedanib treatments 2 day after treatments. * and # denote P < 0.01 vs control and model, respectively.

Figure 3

The expression of HDAC2, IL-8 and VEGF proteins in tracheal tissues from rabbits after tracheal brushing and nintedanib treatments 2 day after treatments. Left panel: representative Western blots, right panel: relative protein level. * and # denote P < 0.01 vs control and model, respectively.

Figure 4

Immunofluorescence assessment of HDAC2 in tracheal tissues from rabbits after tracheal brushing and nintedanib treatments 2 day after treatments. (A) Representative immunofluorescence photos, (B) Immunofluorescence intensity. * and # denote P < 0.01 vs control and model, respectively.

Figure 5

Assessment of collagens I and III expression in tracheal tissues from rabbits after tracheal brushing and nintedanib treatments 2 day after treatments. A. Immunohistochemistry staining; B. Relative cell numbers. * and # denote P < 0.01 vs control and model, respectively.