Hypoxia inhibits fibroblast collagen deposition in tracheoesophageal fistulas through autophagy.

X. Xu^a (Dr), J. Li*^a (Prof), J. Cui^a (Dr), Z. Liu^a (Dr), Y. Wang^a (Dr), S. Li^a (Dr), D. Chen^a (Dr)

^a Guangdong Provincial People's Hospital, Guangzhou, CHINA

* 472522080@qq.com

Objective

To explore the mechanism of hypoxia-mediated autophagy in the formation of post intubation tracheoesophageal fistula.

Methods

1. Detect the expression of HIF-1α and α-SMA in normal tracheal tissue samples and tracheoesophageal fistula samples by immunohistochemistry;
2. Divide the tracheal fibroblasts into 2 groups: Normoxia group and hypoxia group. The two groups of cells were cultured in 21% O2 and 1% O2 incubators respectively, and the migration capacity of the two groups of cells at 0h, 12h, and 24h was determined by scratch experiment; after the two groups of cells were cultured for 12h, the cells were collected to extract protein, and the expression of HIF-1α and α-SMA and autophagy-related proteins and Col-1 was determined by Western Blot method; the expression of α-SMA was analyzed by cell immunofluorescence.
3. The experiment was divided into four groups: Normoxia group (21% O2), hypoxia group (1% O2), CQ (10 μM, 24h) + hypoxia group (1% O2, 12h), RP (1 μM, 24h) + hypoxia group (1% O2, 12h). α-SMA and Col-1 expression were determined by immunofluorescence and Western Blot respectively.

Results

1. Expression of HIF-1α and α-SMA in tracheoesophageal fistulas is increased.

2. Hypoxia had no effect on the migration ability of tracheal fibroblasts.

3. Under hypoxic condition, the expression of HIF-1α and α-SMA in human tracheal fibroblasts is increased.

4. Under hypoxic condition, the autophagy activity of tracheal fibroblasts is enhanced, and expression of Col-1 is reduced.

5. Under hypoxic condition, autophagy activity was inversely correlated with Col-1 expression in tracheal fibroblasts

Conclusion

Hypoxia promotes the differentiation of tracheal fibroblasts into myofibroblasts. Under hypoxic conditions, the autophagy flux of tracheal fibroblasts increases, inhibiting the production of tracheal fibrosis, possibly by promoting the breakdown of collagen in tracheal fibroblasts.

Key words : Hypoxia, Benign acquired tracheoesophageal fistula, Tracheal fibroblasts, Autophagy

Disclosure of funding source(s): none