The Effects Of Pirfenidone And N-Acetylcysteine On The Expression Of RELM-beta In The Mice Pulmonary Fibrosis

Obsjectives:To study the expression and significance of RELM-beta and investgate the effect of pirfenidone and N-acetylcysteine on the expression of RELM-beta in the pulmonary fibrosis of mice.Methods:72female C57BL/6mice were randomly divided into four groups(18mice in each group):the normal control group(group C), the model group(group M), the pirfenidone group(group P) and the N-acetylcysteine group(group N), and then each group was randomly divided into3subgroups according to the7th,14th and28th of three observation time points. The mice models of pulmonary fibrosis of group M, group P and group N were established by a single intracheal instillation of bleomycin at a dose of3.5mg/kg, and the mice of group C were treated with the same volume of saline instead of bleomycin. The mice of group P were given pirfenidone by intragastric administration after the model of pulmonary fibrosis established, but the mice of group C and group M were given the same volume of saline instead by intragastric administration. The mice of group N were given N-acetylcysteine by intragastric administration before establishing the model of pulmonary fibrosis. On the7th,14th or28th day,6mice were randomly killed at each observation time point, and their lungs were harvested for the measurements of lung coefficient and hydroxyproline concentration, pathology change which contained hemotoxylin-eosin staining and Masson’s staining. The expression of RELM-beta in mice lungs was analysised by immnohistochemistry.Result (1) Lung coefficient:The lung coefficient of group M was increased compared with group C(P<0.05), the more significantly increased on the7th day; The lung coefficients of group P and group N were lower than that of group M(P<0.05).(2) The hydroxyproline concentrations:The hydroxyproline concentrations in the lungs of group M, group P and group N on all the observation time points were higher than that of group C(P<0.05), and the hydroxyproline concentrations displayed gradually increasing; The hydroxyproline concentrations of group P and group N were lower than that of group M(P<0.05).(3) The alveolitis and pulmonary fibrosis of lung tissue: The Szapiel scores of HE staining of lung tissue showed that the scores of group M was significantly increased compared with that of group C(P<0.05), which was the highest on the7th day, but there was no significant different between group P and group N(P>0.05). The Szapiel scores of Masson’s staining of lung tissue showed the score of pulmonary fibrosis of group M was significantly inceased compared with that of group C, which was the highest on the28th day, and the scores of group P and group N were markable lower than that of group M(P<0.05), but there was no difference of the scores between group P and group N(P>0.05).(4) The expressions of RELM-beta in lung tissue:The expression of RELM-beta of group M was higher than that of group C, which was gradually increased over all the observation times, and it was increased significantly on the28th day, and the expression of RELM-beta of group P and group N were decreased compared with that of group M(P<0.05).Conclusion (1) We made the pulmonary fibrosis model of mice successfully by a single intracheal instillation of bleomycin (3.5mg/kg) in this study.(2) In the formative procedure of pulmonary fibrosis, the expression of RELM-beta was dynamic, which was gradually increased over time and its expression was stronger on the28th day.(3) Pirfenidone and N-acetylcysteine may reduce the degrees of alveolitis and pulmonary fibrosis by decreasing the expression of RELM-beta. It suggested that RELM-beta may become a new target in the treatment of pulmonary fibrosis.