Iranian Journal of Pharmaceutical Research (2004): Supplement 2:
2nd International Congress on Traditional Medicine and Materia Medica
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
Mikaili P., Sarahroodi S., Hemmati A.A., Koochak M.H., Dezfoulian., Akbari Z.,
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<0.01). (2) In the microscopical examination for the number of tracheal epithelial cells, the group exposed to nebulized extract of Althea officinalis had a significant increase (p<0.01) and the group receiving cigarette smoke had a significant decrease (p<0.05) in comparison to the control group. (3) In the histological examination of tracheal submucosa, the group exposed to cigarette smoke had significant increase in the Reid Index, compared to the control group (p<0.05). (4) There were no significant differences between extract treated group (fourth group) and the control group (p>0.05).
The findings from this study demonstrated that cigarette smoke induced structural changes on epithelial cells which was manifested by a significant squamous metaplasia, a significant reduction in the number of goblet and and other secretory cells, and a significant increase in the Reid Index. We showed that Althea officinalis prevented the development of the cellular injuries that followed cigarette smoke and it not only prevented cigarette induced proliferative effects on the squamous cells of epithelial layer and reduced the Reid index significantly, but also increased the number of goblet cells and promoted MCT. This latter effect was inferred from the observed reduction of glycoprotein accumulation in the treated group. So, we may suggest the use of Althea officinalis extract to prevent or alleviate the toxic effects of cigarette smoke in the smokers.