FN1 and pulmonary fibrosis: To confirm the establishment and improvement of lung fibrosis after the challenge with BLM and treatment with VCN, certain markers were selected for this purpose which includes tissue collagen deposition determined by histological scoring of fibrosis and measurement of tissue hydroxyproline (an indicator for newly formed collagen), measurement of serum level of collagen type IV and KL-6, as well as determination of presence of fibronectin, vimentin, and α-SMA by immunostaining which are markers for ECM synthesis and indicators for myofibroblasts formation (especially α-SMA).