Effects of different drugs on bronchial stenosis by TGF-β/mTOR signaling pathway in rabbit model

Abstract

Objective: To investigate the effect of different drugs on tracheal stenosis caused by transforming growth factor-β/rapamycin target protein (TGF-β/mTOR) signaling pathway. Methods: Thirty rabbits were randomly divided into normal control group, normal saline group, penicillin group, budesonide group and erythromycin group. The normal control group was not treated,and tracheal stenosis models were established in the other groups. From the 1st to 10th day after modeling, each group was respectively administered with normal saline (0.75 ml/kg, 2 times/d), intramuscular injection of penicillin (40 000 U/kg, 2 times/d), gastric administration of erythromycin (12.5 mg/kg, 2 times/d), inhalation of budesonide (0.05 mg/kg, 2 times/d). Rabbits were sacrificed on the 11th day after surgery, and tracheal specimens were collected to measure the degree of tracheal stenosis. Relative mRNA expression level of interleukin-6 (IL-6), transforming growth factor-β (TGF-β), Type Ⅰ collagen (COL-1), Type Ⅲ collagen (COL-3), and Sirtuin 1 (SIRT-1) were detected by Real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR); protein expression of mTOR, phosphorylated protein kinase B (p-AKT), vascular endothelial growth factor (VEGF),SIRT-1 were detected by immunohistochemical analysis; protein expression of nuclear factor κB (NF-κB),phosphorylated nuclear factor κB (p-NF-κB),protein kinase B (AKT),p-AKT,mTOR were detected by Western blotting. Results: The degree of stenosis of normal control group was (14.02±2.86)%, saline group was (64.14±3.21)%, penicillin group was (49.11±2.96)%, budesonide group was (39.52±2.09)%, erythromycin group was (32.60±4.27)%. The differences between any two groups were statistically significant (all P<0.05). Except between erythromycin group and normal control group, the differences in relative expression of IL-6 mRNA between any two groups (1.00±0.00, 9.02±1.50, 4.25±0.87, 2.53±0.17, 1.31±0.56) was statistically significant (all P<0.05), and the differences in relative expression of TGF-β mRNA among all groups (1.00±0.00, 6.92±0.84, 3.83±0.44, 2.13±0.25, 1.40±0.15) were statistically significant (all P<0.05). The relative expression of SIRT-1 mRNA among all the groups (1.000±0.000, 0.209±0.042, 0.375±0.034, 0.555±0.028, 0.667±0.032) was statistically significant different (all P<0.05); except between erythromycin group and budesonide group,the protein levels of SIRT-1 among all other groups (16.93±2.28, 4.77±1.45, 7.70±0.61, 10.76±1.04, 11.03±1.10) were statistically significant different (all P<0.05). The protein levels of mTOR (9.28±4.56, 58.18±8.12, 44.75±5.56, 32.82±5.99, 24.73±3.56) and p-AKT (16.57±4.86, 61.79±6.66, 42.98±5.99, 32.79±5.34, 24.00±4.40) determined through immunohistochemistry of all groups were statistically significant different (all P<0.05). The protein levels of NF-κB, p-NF-κB, AKT, p-AKT and mTOR determined through Western blotting had the same trend as that of determined through immunohistochemistry. The protein expression of NF-κB,AKT and mTOR in saline group were significantly higher than other groups; those protein expression of erythromycin group was lower than budesonide group and penicillin group. Except between the erythromycin group and the normal control group, the protein expression of mTOR in other groups was statistically significant different (all P<0.05). Conclusion: Penicillin,erythromycin and budesonide can alleviate inflammation by increasing SIRT-1, alleviate tracheal scar hyperplasia induced by TGF-beta/mTOR pathway, and reduce the degree of tracheal stenosis in rabbits.