Antifibrotic effect of decorin in a bleomycin hamster model of lung fibrosis

• Published in: Biochemical pharmacology 1997-12, Vol.54 (11), p.1205-1216
• Main Authors: Giri, Shri N., Hyde, Dallas M., Braun, Ruedi K., Gaarde, William, Harper, John R., Pierschbacher, Michael D.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Bleomycin - toxicity; collagen; Cricetinae; Decorin; Extracellular Matrix Proteins; fibronectin; Hydroxyproline - analysis; Immunohistochemistry; Lung - chemistry; Lung - pathology; Male; Medical sciences; Mesocricetus; Peroxidase - metabolism; Pharmacology. Drug treatments; Procollagen-Proline Dioxygenase - metabolism; Proteoglycans - therapeutic use; pulmonary fibrosis; Pulmonary Fibrosis - drug therapy; Pulmonary Fibrosis - metabolism; Pulmonary Fibrosis - pathology; Respiratory system; Superoxide Dismutase - metabolism; transforming growth factor-β
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/S0006-2952(97)00343-2

We reported previously that treatment with antibody to transforming growth factor-β (TGF-β) caused a marked attenuation of bleomycin (BL)-induced lung fibrosis (LF) in mice. Decorin (DC), a proteoglycan, binds TGF-β and thereby down-regulates all of its biological activities. In the present study, we evaluated the antifibrotic potential of DC in a three-dose BL-hamster model of lung fibrosis. Hamsters were placed in the following groups: (1) saline (SA) + phosphate-buffered saline (PBS) (SA + PBS); (2) SA + DC; (3) BL + PBS; and (4) BL + DC. Under pentobarbital anesthesia, SA (4 mL/kg) or BL was instilled intratracheally in three consecutive doses (2.5, 2.0, 1.5 units/kg/4 mL) at weekly intervals. DC (1 mg/mL) or PBS was instilled intratracheally in 0.4 mL/hamster on days 3 and 5 following instillation of each dose of SA or BL. In week 4, hamsters received three doses of either DC or PBS every other day. The hamsters were killed at 30 days following the first instillation, and their lungs were appropriately processed. Lung hydroxyproline levels in SA + PBS, SA + DC, BL + PBS, and BL + DC groups were 965, 829, 1854, and 1387 μg/lung, respectively. Prolyl hydroxylase activities were 103, 289, and 193% of SA + PBS control in SA + DC, BL + PBS, and BL + DC groups, respectively. The myeloperoxidase activities in the corresponding groups were 222, 890, and 274% of control (0.525 units/lung). Intratracheal instillation of BL caused significant increases in these biochemical markers, and instillation of DC diminished these increases in the BL + C group. DC treatment also caused a significant reduction in the infiltration of neutrophils in the bronchoalveolar lavage fluid (BALF) of hamsters in the BL + DC group. However, DC treatment had little effect on BL-induced increases in lung Superoxide dismutase activity and lipid peroxidation and leakage of plasma proteins in the BALF of the BL + DC group. Hamsters in the BL + PBS group showed severe multifocal fibrosis and accumulation of mononuclear inflammatory cells and granulocytes. In contrast, hamsters in the BL + DC group showed mild multifocal septal thickening with aggregations of mononuclear inflammatory cells. Hamsters in both control groups (SA + PBS and SA + DC) showed normal lung structure. Frozen lung sections following immunohistochemical staining revealed an intense staining for EDA-fibronectin and collagen type I in the BL + PBS group as compared with all other groups. It was concluded that DC potentiall