[Expression and significance of autophagy in rabbit model of tracheal stenosis].

Objective: To investigate the expression and significance of autophagy in rabbit model of tracheal stenosis. Methods: A total of 18 rabbits were equally divided into 3 groups (blank control group, saline group, erythromycin group) in accordance with the random number table. After rabbit model of tracheal stenosis was established, no treatment was done with blank control group. Saline group was atomized with saline (0.54 mg/kg, 2 times/day), and erythromycin group was fed on erythromycin (7.5 mg/kg, 2 times/day) for 7 days before and 10 days after the operation. On the eleventh day, rabbits were executed, and their trachea were collected. The proportion of collagen fiber area of tracheal lamina propria (LP) and epithelium (EP) was assessed by Masson staining. The mRNA of autophagy associated gene-3 (ATG3) and autophagy associated gene-5 (ATG5) of tracheal mucosa were assessed by Real-Time Polymerase Chain Reaction (RT-PCR). The protein of microtubule-associated protein 1 light chain β(3) (LC3B), ATG3 and ATG5 were assessed by Western blot. Results: The proportion of collagen fiber area of tracheal LP and EP of blank control group was (6.79±0.67)%, saline group was (40.55±5.40)%, erythromycin group was (27.48±0.43)%. The differences between any two groups was all statistically significant (all P <0.01). The relative value of ATG3 mRNA and ATG5 mRNA in saline group were significantly lower than blank control group (all P <0.01). Those value in erythromycin group were significantly higher than the saline group (all P <0.01). The protein levels of LC3B-Ⅱ/Ⅰ, ATG3 and ATG5 in saline group were significantly lower than blank control group (all P <0.01). After low dose of erythromycin intervention, all the protein levels were significantly higher than the saline group (all P <0.01). Conclusions: The expression of autophagy is decreased in rabbit model of trachea stenosis. Low dose of erythromycin could increase the expression of autophagy and at the same time alleviate the degree of fibrosis of the tracheal mucosa. Autophagy may alleviate tracheal fibrosis through up-regulating its expression level and play a protective role.