Influence of Maimendong Tang on lung function and endoplasmic reticulum stress in rats with pulmonary fibrosis.

Objective To investigate the relative mechanism of Maimendong Tang (Ophiopogon Decoction) in amelioration of lung function and endoplasmic reticulum stress (ERS) in rats with bleomycin-induced pulmonary fibrosis. Methods Male healthy SD rats were randomly divided into normal group, model group, Maimendong Tang group 1 and Maimendong Tang group 2. The rat model of pulmonary fibrosis was established by bleomycin pulverization via tracheal intubation. On the 14th d after modeling, Maimendong Tang was intragastrically given to Maimendong Tang group 1 and Maimendong Tang group 2 twice a day for 20 d continuously. The general conditions were observed, and pathological changes of lung tissue were observed after HE and Masson staining. The forced vital capacity (FVC), 0.4 second rate (FEV 0.4/FVC), mass FVC, inspiratory resistance (Ri), expiratory resistance (Re) and dynamic pulmonary compliance (Cydn) were detected by using spirometer. The expressions of glucose regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) protein in lung tissue were analyzed by using Western blotting assay and immunohistochemistry staining technique. Results Compared wth normal group, FVC, FVC/ lung mass and Cydn decreased, and 0.4 second rate increased in model group. Compared with model group, FVC increased and 0.4 second rate decreased and Cydn increased in Maimendong Tang group 1 and Maimendong Tang group 2, and mass FVC increased in Maimendong Tang group 2. Pathological sections showed that there were chronic inflammatory cell infiltration in consolidation zone of lung tissue and massive collagen deposition, GRP78 and CHOP with high expressions were mainly positioned in vesicular type II alveolar epithelial cells (AECIIs). The inflammation was relieved, collagen deposition was decreased, protein expressions of GRP78 and CHOP were reduced and in Maimendong Tang group 2. Conclusion Maimendong Tang can significantly improve lung function and reduce lung interstitial collagen deposition, which may be related to regulation of protein expressions of GRP78 and CHOP in AECIIs in consolidation zone of lung tissue, relief of ERS, and recovery of normal AECIIs function. [ABSTRACT FROM AUTHOR]