Objective: To investigate the effect of Dragon's Blood on the expression of TGF-beta signal transduction molecule TGFbetaR II or Smad4 mRNA in the lung tissue of rats with pulmonary fibrosis, and to evaluate the effect and its mechanism of Dragon's Blood on pulmonary fibrosis.
Methods: 30 SD rats were randomly divided into three groups: fibrosis model, treatment and normal control groups. In model group and treatment group, the pulmonary fibrous tissues were induced to form with the intratracheal injection of bleomycin (5 mg/kg). In normal control group, saline was given intratracheally. Dragon's Blood was administered intragastricly in treatment group with a dose of 180 mg/kg diluted in 2 mL saline while saline was given intragastricly to other two groups with same volume from day 2 till day 28 after modeling. All rats were sacrificed on the 29th day. The rat lung histopathology was examined with HE staining. In situ hybridization was used to detect the expressions of TGFbetaR II and Smad4 mRNAs in lung tissue, and the expression of collagen fibril I was examined by an immunohistochemical staining.
Results: The inflammation cell counting in treatment group (12913.78 +/- 5640.12) was significant lower than that in model group (22243.60 +/- 5011.55, P < 0.01). The expression of pulmonary TGF/betaR II mRNA in treatment group was significant lower than that in model group (P < 0.01). In the Smad4 mRNA expression of lung tissue, there was no significant difference occurring between treatment group and model group (P > 0.05). The expression of collagen fibril I in the lung tissue of rats in treatment group was significant lower than that in model group (P < 0. 01).
Conclusion: Dragon's Blood can effectively reduce rats' pulmonary fibrosis, of which the mechanisms may be to inhibit the expression of TGFbetaR II mRNA in the lung tissue and thus to have the preventive effect on the excessive deposit of collagen fibril I.