Effect of hydroalcoholic and aqueous extracts of Dracocephalum kotschyi on bleomycin induced pulmonary fibrosis

Dracocephalum kotschyi is an Iranian traditional medicine with antiinflammatory and bronchodilatory properties. The objective of this research was to investigate the preventive effect of D. kotschyi extract in bleomycin induced fibrosis.

Fibrosis was induced by intratracheal administration of a single dose of bleomycin (5 mg/kg) in rat. One group received daily administration of normal saline. Other groups were treated daily with oral administration of either hydroalcoholic or aqueous extract of D. kotschyi (20, 40, & 80 mg/kg). Another group was treated with pirfenidone (100 mg/kg). After 4 weeks daily treatments, the animals were sacrificed and the whole lungs were dissected out for biochemical and histopathological examinations. The biochemical examination included assessment of hydroxyproline and malondialdehyde levels.

The lung tissues in bleomycin treated groups showed severe tissue injuries. However, lung tissues in the groups that received hydroalcoholic or aqueous extracts of D. kotschyi showed mild to moderate tissue injuries. Intratracheal instillation of bleomycin significantly increased hydroxyproline and malondialdehyde biomarker levels compared with the sham group. In the positive control group treated with pirfenidone, there was a mark reduction in both hydroxyproline and malondialdehyde levels. Both hydroalcoholic and aqueous extracts of D. kotschyi significantly prevented elevation of hydroxyproline and malondialdehyde levels at the above oral doses in comparison to the vehicle treated control group.

Prevention of hydroxyproline and malondialdehyde elevation levels in this experiment indicates that D. kotschyi extract might be a suitable remedy for treatment of respiratory fibrosis induced by drugs such as bleomycin.