The Establishment Of Lung Slice Fibrosis Induced By Transforming Growth Factor-β1 And Inhibitory Effect Of FR167653 On Bleomycin Induced Pulmonary Fibrosis In Rats With Its Partial Mechanism

AimTo establish the lung slice fibrosis model induced by transforming growth factor-β1 (TGF-β1). To investigate the effect of FR167653, a dual inhibitor of tumor necrosis factor-a (TNF-a) and interleukin-1β (IL-1β), on bleomycin-induced pulmonary fibrosis in rats and its possible mechanism.Methods1. The lung slice viability was assessed through lactate dehydrogenase (LDH) leakage and MTT assay after incubation of 1, 3, 5, 7, 9 days. The proper time and dose of TGF-β1-induced lung slice fibrosis and effect of hydrocortisone were investigated via measurement of hydroxyproline (HYP), and lung slice fibrosis was pathological examined with HE and Masson staining.2. Pulmonary fibrosis was induced in SD rats by intratracheal instillation of bleomycin (5 mg/kg). Then the rats received daily FR167653 (4, 12 and 36 mg/kg, sc) or prednisone (20 mg/kg, ig). Histological changes of the lungs were evaluated by HE and Massion staining. The levels of TNF-a and IL-ip in serum were measured with ELISA.Results1. The establishment of lung slice fibrosis induced by transforming growth factor-pl(1) The lung slice was viable for up to 9 days. The change of LDH level in supernatants of lung slice firstly rised up and then lowered down. The MTT level maintained steadily, with a 28.4% fluctuation. And it was descending with the decrease of concentration of 3-nitropropionic acid. Its IC50 is 1.72x10-5 mol/1.(2) The proper time and dose of TGF-pl-induced lung slice fibrosis were 7 days and 2.5 ug/1 respectively.(3) HE staining showed that heterogeneous distribution of fibrosis with a little inflammatory cells infiltration in TGF-J31 (2.5 |J.g/l) group, compared with control group. Masson staining also showed that large amounts of collagen deposited in lung tissue in TGF-pi (2.5 ug/1) group(4) Hydrocortisone (0.1mg/l) did not decrease the HYP levels in lung slices of TGF-pi-induced fibrosis.2. Inhibitory effect of FR167653 on bleomycin induced pulmonary fibrosis in rats and its partial mechanism(1) The body weight and Indices of lung in the model group was significantly lowered down when compared with the sham group at day 7, 14, and 21. The HYP contents in lung tissues were significantly increased in lung fibrosis rats. HE and Masson staining showed that lung tissue from the model group displayed inflammatory cells infiltration, thickened alveolar walls and large amounts of collagen deposition. However, FR167653 group showed the opposite results.(2) In the serum from rats that were pretreated with bleomycin, significant amounts of TNF-a and IL-ip were detected. The augmentation of TNF-a and IL-ip levels was significantly reduced with the administration of FR167653 (12, 36 mg/kg).Conclusions1. TGF-pi (2.5 u.g/1, x7d) could induce lung slice fibrosis.2. Hydrocortisone (0.1 mg/1) did not exert advantageous effect on this process.3. FR167653 had an inhibitory effect on pulmonary fibrosis induced by bleomycin.4. Effect of FR167653 on bleomycin induced pulmonary fibrosis would be associated with its reduction of TNF-a and IL-1(3 levels in serum of rats.