Objective: To observe the effects of Feixian Formula, a compound traditional Chinese herbal medicine for treating pulmonary fibrosis, on bleomycin-induced pulmonary fibrosis in rats, and its influence on serum transforming growth factor-beta1 (TGF-beta1) and platelet-derived growth factor (PDGF).
Methods: Seventy-two male Wistar rats were infused with bleomycin (1 mg/kg) through tracheal intubation to induce pulmonary fibrosis, and they were randomly divided into untreated group (n=24), prednisone-treated group (n=24) and Feixian Formula-treated group (n=24). Fifteen male Wistar rats of the sham-operated group were infused with equivalent normal saline. Twenty-four hours after operation, prednisone (5 mg/kg) and Feixian Formula (1.25 g/kg) were given to the prednisone-treated group and Feixian Formula-treated group respectively by intragastric administration once a day. Equivalent saline was administered to rats of the untreated group and sham-operated group. On the 14th, 28th and 45th day, 5 rats in the sham-operated group and 8 rats in each of the other three groups were dissected to observe pathologic changes of the lung tissues, and the levels of serum TGF-beta1 and PDGF were determined by enzyme-linked immunosorbent assay.
Results: At the 45th day, the degree of pulmonary interstitial fibrosis was lesser in rats of the Feixian Formula-treated group as compared with those of the untreated group and prednisone-treated group. The levels of serum TGF-beta1 and PDGF were increased, and were significantly higher than those of the sham-operated group, especially on the 45th day (P<0.05). Changes of TGF-beta1 level in the prednisone-treated group and the Feixian Formula-treated group were similar to untreated group (P>0.05), and there was no significant difference between the prednisone-treated group and the Feixian Formula-treated group (P>0.05). PDGF in the Feixian Formula-treated group reached the highest level on the 14th day, significantly higher than those of the other three groups (P<0.01). Then it decreased, and was close to that of the sham-operated group on the 45th day (P=0.792). The levels of PDGF in untreated group and prednisone-treated group were increased depending on time, and were obviously higher than that of the sham-operated group on the 45th day (P<0.01).
Conclusion: Feixian Formula can relieve bleomycin-induced pulmonary fibrosis in rats, and the mechanism of its action may be related to down-regulating serum PDGF.