A histological study on the effects of aqueous extract of Althea officinalis on epithelial and submucosal mucocilliary system of rat trachea following inhalation of cigarette smoke

The contents of cigarette smoke (gaseous and solid phases) have been attributed to a variety of diseases in the respiratory and cardiovascular systems and have been associated with development of different types of cancers. In respiratory system, these compounds specially cause epithelial cell injury, and interfere with mucocilliary transport (MTC). Various parts of Althea officinalis (family Malvaeceae), known as Khatmi (in Persian), are commonly used in Iranian traditional medicine in treatment of acute bronchitis, pneumonia etc. Thus, we conducted a study to evaluate the effectiveness of the aqueous extract of flower part of this plant in the treatment of epithelial and submucosal cell injuries produced following experimental exposure to cigarette smoke in an experimental setting in rat. In this study the rats of either sexes were divided into 4 groups (n=5). First group (control group) received 1 ml normal saline every 12 hours. Second group was nebulized by 1 ml of Althea extract (100 mg/ml) twice daily. Third group was exposed to smoke of four cigarettes in a chamber for 1 hour. Fourth group was nebulized with 1 ml Althea extract as the second group but after the first dose of extract, animals were exposed to cigarette smoke for 1 hour. After 10 days, the animals were euthanized through IP injection of sodium thiopental (200 mg/kg) then trachea was removed and prepared for histological examination, using H&E and PAS staining. The results of this study revealed that (1) the group receiving cigarette smoke had a significant increase in occurrence of metaplasia in comparison to other groups (p